Alpha blockers

Health topics by Health Jade Team on April 10, 2019 9.33K views

What are alpha blockers

Alpha blockers also called alpha-adrenergic antagonists or alpha adrenergic blockers, relax certain muscles and help small blood vessels remain open. Alpha blockers work by keeping the hormone norepinephrine (noradrenaline) from tightening the muscles in the walls of smaller arteries and veins, which causes the vessels to remain open and relaxed. This improves blood flow and lowers blood pressure.

Because alpha blockers also relax other muscles throughout the body, these medications can help improve urine flow in older men with benign prostatic hyperplasia (BPH).

Alpha blocker drugs

Several alpha blockers are available, in either short-acting or long-acting forms. Short-acting medications work quickly, but their effects last only a few hours. Long-acting medications take longer to work, but their effects last longer. Which alpha blocker is best for you depends on your health and the condition being treated.

Alpha blockers are also called alpha-adrenergic blocking agents, alpha-adrenergic antagonists, adrenergic blocking agents and alpha-blocking agents.

Examples of alpha blockers used to treat high blood pressure include:

Doxazosin (Cardura)
Prazosin (Minipress)
Terazosin

Examples of alpha blockers used to treat men with enlarged prostate (BPH) include:

Alfuzosin
Doxazosin
Silodosin
Tamsulosin
Terazosin

Alfuzosin

Alfuzosin is used in men to treat symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH), which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. Alfuzosin is in a class of medications called alpha blockers. It works by relaxing the muscles in the prostate and bladder to allow urine to flow more easily.

Alfuzosin comes as an extended-release (long-acting) tablet to take by mouth. It is usually taken once a day, immediately after a meal. Do not take alfuzosin on an empty stomach. To help you remember to take alfuzosin, take it after the same meal every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take alfuzosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets whole; do not split, chew, or crush them.

Alfuzosin controls BPH but does not cure it. Continue to take alfuzosin even if you feel well. Do not stop taking alfuzosin without talking to your doctor.

What should I do if I forget a dose?

Alfuzosin special precautions

Before taking alfuzosin:

tell your doctor and pharmacist if you are allergic to alfuzosin, any other medications, or any of the ingredients in alfuzosin. Ask your pharmacist for a list of the ingredients.
tell your doctor if you are taking itraconazole (Sporanox), ketoconazole (Nizoral), or ritonavir (Norvir, in Kaletra). Your doctor will probably tell you not to take alfuzosin.
tell your doctor if you have liver disease. Your doctor may tell you not to take alfuzosin.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: amiodarone (Cordarone); aprepitant (Emend); atenolol (Tenormin); cimetidine (Tagamet); cisapride (not available in the U.S.); clarithormycin (Biaxin, in Prevpac); cyclosporine (Neoral, Sandimmune); danazol (Danocrine); delavirdine (Rescriptor); diltiazem (Cardizem, Dilacor, Tiazac, others); disopyramide (Norpace);dofetilide (Tikosyn); efavirenz (Sustiva); erythromycin (E.E.S., E-Mycin, Erythrocin);fluconazole (Diflucan); fluoxetine (Prozac, Sarafem); fluvoxamine (Luvox); HIV protease inhibitors such as atazanavir (Reyataz), indinavir (Crixivan), lopinavir (in Kaletra), nelfinavir (Viracept), and saquinavir (Fortovase, Invirase); hormonal contraceptives (birth control pills, rings, and patches); isoniazid (INH, Nydrazid); lovastatin (Adivicor, Altocor, Mevacor); medications for high blood pressure; medications for erectile dysfunction (ED) such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra); metronidazole (Flagyl); moxifloxacin (Avelox); nefazodone; other alpha blockers such as doxazosin (Cardura), prazosin (Minipress), terazosin (Hytrin), and tamsulosin (Flomax); pimozide (Orap); procainamide (Procanbid, Pronestyl); quinidine (Quinidex); sertraline (Zoloft); sotalol (Betapace,); sparfloxacin (Zagam); thioridazine (Mellaril); troleandomycin (TAO); verapamil (Calan, Covera, Isoptin, Verelan); and zafirlukast (Accolate). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you or any member of your family have an irregular heartbeat; or if you have or have ever had prostate cancer; angina (chest pain); low blood pressure; or heart or kidney disease; and if you have ever become dizzy, fainted, or had low blood pressure after taking any medication.
you should know that alfuzosin is only for use in men. Women should not take alfuzosin, especially if they are or could become pregnant or are breast-feeding. If a pregnant woman takes alfuzosin, she should call her doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking alfuzosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken alfuzosin.
you should know that alfuzosin may cause dizziness, lightheadedness, and fainting, especially when you get up too quickly from a lying position. This is more common when you first start taking alfuzosin. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If these symptoms do not improve, call your doctor. Avoid driving, operating machinery, or performing dangerous tasks until you know how this medication affects you.

Alfuzosin side effects

Alfuzosin may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section are severe or do not go away:

tiredness
headache
runny or stuffy nose
pain
stomach pain
heartburn
constipation
nausea
decrease in sexual ability
sore throat, fever, chills, cough and other signs of infection

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

rash
swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
hoarseness
difficulty swallowing or breathing
chest pain
fainting

Symptoms of alfuzosin overdose may include:

dizziness
fainting
lightheadedness
blurred vision
nausea

Alfuzosin may cause other side effects. Call your doctor if you have any unusual problems while taking alfuzosin.

Doxazosin

Doxazosin is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH), which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. It is also used alone or in combination with other medications to treat high blood pressure. Doxazosin is in a class of medications called alpha-blockers. It relieves the symptoms of BPH by relaxing the muscles of the bladder and prostate. It lowers blood pressure by relaxing the blood vessels so that blood can flow more easily through the body.

High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

Doxazosin comes as a tablet and an extended-release tablet to take by mouth. The doxazosin tablet is usually taken with or without food once a day in the morning or in the evening. Doxazosin extended-release tablet is usually taken once a day with breakfast. Take doxazosin around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take doxazosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the extended-release tablets whole; do not split, chew, or crush them.

Your doctor will start you on a low dose of doxazosin and gradually increase your dose, not more than once every 1 to 2 weeks. If you stop taking doxazosin for a few days or longer, call your doctor. Your doctor will have to start you again on the lowest dose of doxazosin and gradually increase your dose.

Doxazosin controls high blood pressure and the symptoms of BPH but does not cure them. It may take a few weeks before you feel the full benefit of doxazosin. Continue to take doxazosin even if you feel well. Do not stop taking doxazosin without talking to your doctor.

Follow your doctor’s directions for your meals, including advice for a reduced salt (sodium) diet.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. Check with your doctor if you have missed two or more doses.

Doxazosin special precautions

Before taking doxazosin:

tell your doctor and pharmacist if you are allergic to doxazosin, prazosin (Minipress), terazosin, any other medications, or any ingredients in doxazosin tablets or extended-release tablets. Ask your pharmacist for a list of the ingredients..
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antihistamines; clarithromycin (Biaxin, in Prevpac); ipratropium (Atrovent, in Combivent); itraconazole (Onmel, Sporanox); ketoconazole (Nizoral); medications for erectile dysfunction (ED) such as sildenafil (Revatio, Viagra), tadalafil (Adcirca, Cialis), or vardenafil (Levitra, Staxyn); medications for high blood pressure; medications for HIV/AIDS including atazanavir (Reyataz), indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), or saquinavir (Invirase); medications for irritable bowel disease, motion sickness, Parkinson’s disease, ulcers, or urinary problems; nefazodone; telithromycin (Ketek); and voriconazole (Vfend). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have angina (chest pain); low blood pressure; if you have ever had low blood pressure after taking a medication; or if you have or have ever had prostate cancer, or liver disease. If you are taking the extended-release tablet, tell you doctor if you have constipation, short bowel syndrome (a condition where more than half of the small intestine has been removed by surgery or damaged by disease), or narrowing or a blockage of the intestines.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking doxazosin, call your doctor.
talk to your doctor about the risks and benefits of taking doxazosin if you are 65 years of age or older. Older adults should not usually take doxazosin to treat high blood pressure, because it is not as safe as other medications that can be used to treat the same condition.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking doxazosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken doxazosin.
you should know that doxazosin may make you drowsy or dizzy. Do not drive a car, operate machinery, or perform dangerous tasks for 24 hours after the first time you take doxazosin or after your dose is increased.
you should know that doxazosin may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking doxazosin, when your dose is increased, or if your treatment has been stopped for more than a few days. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If you experience these symptoms, sit or lie down. If these symptoms do not improve, call your doctor.

Doxazosin side effects

Doxazosin may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section are severe or do not go away:

headache
tiredness
swelling of the hands, feet, ankles, or lower legs
shortness of breath
weight gain
muscle or joint pain or weakness
abnormal vision
runny nose
decreased sexual ability

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or seek emergency medical treatment:

rapid, pounding, or irregular heartbeat
chest pain
shortness of breath
hives
painful erection of the penis that lasts for hours

Symptoms of doxazosin overdose may include:

drowsiness
dizziness
lightheadedness
fainting
seizure

Doxazosin may cause other side effects. Call your doctor if you have any unusual problems while taking doxazosin.

Prazosin

Prazosin is used alone or in combination with other medications to treat high blood pressure. Prazosin is in a class of medications called alpha-blockers. It works by relaxing the blood vessels so that blood can flow more easily through the body.

High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys, and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

Prazosin is also used to treat benign prostatic hyperplasia (BPH, noncancerous enlargement of the prostate), congestive heart failure, pheochromocytoma (adrenal gland tumor), sleep problems associated with post-traumatic stress disorder (PTSD; an anxiety disorder in people who experience or witness a traumatic, life-threatening event), and Raynaud’s disease (condition where the fingers and toes change skin color from white to blue to red when exposed to hot or cold temperatures). Talk to your doctor about the possible risks of using this medication for your condition.

Prazosin comes as a capsule to take by mouth. It usually is taken two or three times a day at evenly spaced intervals. The first time taking prazosin, you should take it before you go to bed. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take prazosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of prazosin and gradually increase your dose.

Prazosin controls high blood pressure but does not cure it. Continue to take prazosin even if you feel well. Do not stop taking prazosin without talking to your doctor.

What should I do if I forget a dose?

Prazosin special precautions

Before taking prazosin:

tell your doctor and pharmacist if you are allergic to prazosin, alfuzosin (Uroxatral), doxazosin (Cardura), terazosin, any other medications, or any ingredients in prazosin capsules. Ask your pharmacist for a list of the ingredients.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention: beta-blockers such as propranolol (Inderal, InnoPran, in Inderide); medications for erectile dysfunction (ED) such as sildenafil (Revatio, Viagra), tadalafil (Adcirca, Cialis), or vardenafil (Levitra, Staxyn); and other medications for high blood pressure.
tell your doctor if you have narcolepsy (a sleep disorder that may cause extreme sleepiness, sudden uncontrollable urge to sleep during daily activities) or if you have or have ever had prostate cancer or liver disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking prazosin, call your doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking prazosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken prazosin.
you should know that this medication may make you drowsy or dizzy. Do not drive a car, operate machinery, or perform dangerous tasks for 24 hours after the first time you take prazosin or after your dose is increased.
ask your doctor about the safe use of alcoholic beverages while you are taking prazosin. Alcohol can make the side effects from prazosin worse.
you should know that prazosin may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking prazosin, when your dose is increased, or when another blood pressure medication is added to your treatment. To help avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If you experience these symptoms, sit or lie down. These symptoms may also occur if you drink alcohol, stand for long periods of time, exercise, or if the weather is hot. If these symptoms do not improve, call your doctor.
talk to your doctor about the risks and benefits of taking prazosin if you are 65 years of age or older. Older adults should not usually take prazosin to treat high blood pressure, because it is not as safe or effective as other medications that can be used to treat the same condition.

Prazosin side effects

Prazosin may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section are severe or do not go away:

weakness
tiredness
headache
nausea

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately or seek emergency medical treatment:

hives
rash
itching
difficulty breathing
fast, pounding, or irregular heartbeat
chest pain
painful erection of the penis that lasts for hours

Symptoms of overdose may include the following:

drowsiness
decreased reflexes
dizziness
lightheadedness
fainting

Prazosin may cause other side effects. Call your doctor if you have any unusual problems while taking prazosin.

Silodosin

Silodosin is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia; BPH), which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. Silodosin is in a class of medications called alpha-blockers. It relieves the symptoms of BPH by relaxing the muscles of the bladder and prostate.

Silodosin comes as a capsule to take by mouth. It is usually taken with food once a day. Do not take silodosin on an empty stomach. Take silodosin at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take silodosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Silodosin controls the symptoms of BPH but does not cure it. Continue to take silodosin even if you feel well. Do not stop taking silodosin without talking to your doctor.

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine.

What should I do if I forget a dose?

Take the missed dose with a meal as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Silodosin special precautions

Before taking silodosin:

tell your doctor and pharmacist if you are allergic to silodosin or any other medications.
tell your doctor if you are taking antifungals such as ketoconazole (Nizoral) and itraconazole (Sporanox); clarithromycin (Biaxin, in Prevpac); HIV protease inhibitors such as indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), and saquinavir (Fortovase); nefazodone; telithromycin (Ketek). Your doctor will probably tell you not to take silodosin.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: cyclosporine (Neoral, Sandimmune); diltiazem (Cardizem, Dilacor, Tiazac); erythromycin (E.E.S., E-Mycin, Erythrocin); fluconazole (Diflucan); medications for high blood pressure;other alpha blockers such as doxazosin (Cardura), prazosin (Minipress), terazosin (Hytrin), and tamsulosin (Flomax); and verapamil (Calan, Covera, Isoptin, Verelan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with silodosin, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
tell your doctor if you have kidney or liver disease. Your doctor will probably tell you not to take silodosin.
tell your doctor if you have or have ever had low blood pressure.
you should know that silodosin is only for use in men. Women should not take silodosin, especially if they are or could become pregnant or are breast-feeding. If a pregnant woman takes silodosin, she should call her doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking silodosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken silodosin.
you should know that silodosin may make you drowsy or dizzy, especially when you first start taking it. Do not drive a car or operate machinery until you know how this medication affects you.
you should know that silodosin may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking silodosin. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If you experience these symptoms, sit or lie down. If these symptoms do not improve, call your doctor.

Silodosin side effects

Silodosin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

orgasm with little or no semen (fluid)
diarrhea
dizziness
low blood pressure
stuffy or runny nose

Some side effects can be serious. If you experience any of these symptoms , call your doctor immediately:

painful erection of the penis that lasts for several hours

Symptoms of overdose may include:

dizziness
fainting
lightheadedness
blurred vision

Silodosin may cause other side effects. Call your doctor if you have any unusual problems while taking silodosin.

Tamsulosin

Tamsulosin is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH) which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. Tamsulosin is in a class of medications called alpha blockers. It works by relaxing the muscles in the prostate and bladder so that urine can flow easily.

Tamsulosin comes as a capsule to take by mouth. It is usually taken once a day. Take tamsulosin 30 minutes after the same meal each day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take tamsulosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow tamsulosin capsules whole; do not split, chew, crush, or open them.

Your doctor will probably start you on a low dose of tamsulosin and may increase your dose after 2 to 4 weeks.

Tamsulosin may help control your condition, but it will not cure it. Continue to take tamsulosin even if you feel well. Do not stop taking tamsulosin without talking to your doctor.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. If you interrupt your treatment for several days or longer, call your doctor before restarting the medication, especially if you take more than one capsule of tamsulosin a day.

Tamsulosin special precautions

Before taking tamsulosin:

tell your doctor and pharmacist if you are allergic to tamsulosin, sulfa medications, or any other medications.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements and herbal products you are taking or plan to take. Be sure to mention any of the following: other alpha blocker medications such as alfuzosin (Uroxatral), doxazosin (Cardura), prazosin (Minipress), and terazosin (Hytrin); anticoagulants (‘blood thinners’) such as warfarin (Coumadin); cimetidine (Tagamet); and medications for erectile dysfunction (ED) such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra); Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.
tell your doctor if you have or have ever had prostate cancer or liver or kidney disease.
you should know that tamsulosin is only for use in men. Women should not take tamsulosin, especially if they are pregnant or could become pregnant or are breast-feeding. If a pregnant woman takes tamsulosin, she should call her doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking tamsulosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken tamsulosin.
you should know that this medication may make you drowsy or dizzy. Do not drive a car, operate machinery, or perform dangerous tasks until you know how this medication affects you.
you should know that tamsulosin may cause dizziness, lightheadedness, a spinning sensation, and fainting, especially when you get up too quickly from a lying position. This is more common when you first start taking tamsulosin or after your dose is increased. To help avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. Call your doctor if these symptoms are severe or do not go away.

Tamsulosin side effects

Tamsulosin may cause side effects. Tell your doctor if any of these symptoms or those in the SPECIAL PRECAUTIONS section are severe or do not go away:

sleepiness
difficulty falling asleep or staying asleep
weakness
back pain
diarrhea
runny or stuffy nose
pain or pressure in the face
sore throat, cough, fever, chills, or other signs of infection
blurred vision
difficulty ejaculating

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

painful erection of the penis that lasts for hours
rash
itching
hives
swelling of the eyes, face, tongue, lips, throat, arms, hands, feet, ankles, or lower legs

Symptoms of overdose may include:

dizziness
fainting
blurred vision
upset stomach
headache

Tamsulosin may cause other side effects. Call your doctor if you have any unusual problems while taking tamsulosin.

Terazosin

Terazosin is used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia or BPH), which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency. It also is used alone or in combination with other medications to treat high blood pressure. Terazosin is in a class of medications called alpha-blockers. It relieves the symptoms of BPH by relaxing the muscles of the bladder and prostate. It lowers blood pressure by relaxing the blood vessels so that blood can flow more easily through the body.

High blood pressure is a common condition, and when not treated it can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

Terazosin comes as a capsule to take by mouth. It is usually taken with or without food once a day at bedtime or twice a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take terazosin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will start you on a low dose of terazosin and gradually increase your dose. If you stop taking terazosin for a few days or longer, call your doctor. Your doctor usually will start you again on the lowest dose of terazosin and gradually increase your dose.

Terazosin controls high blood pressure and the symptoms of BPH but does not cure them. It may take 4 to 6 weeks or longer before you feel the full benefit of terazosin for BPH. Continue to take terazosin even if you feel well. Do not stop taking terazosin without talking to your doctor.

What should I do if I forget a dose?

Terazosin special precautions

Before taking terazosin:

tell your doctor and pharmacist if you are allergic to terazosin, doxazosin (Cardura, Cardura XL), prazosin (Minipress), any other medications, or any ingredients in terazosin capsules. Ask your pharmacist for a list of the ingredients.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: medications for erectile dysfunction (ED) such as sildenafil (Revatio, Viagra), tadalafil (Adcirca, Cialis), or vardenafil (Levitra, Staxyn); and other medications for high blood pressure, especially verapamil (Calan, Covera, Verelan, in Tarka). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have or have ever had prostate cancer.
tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking terazosin, call your doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking terazosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken terazosin.
you should know that terazosin may make you drowsy or dizzy. Do not drive a car, operate machinery or perform dangerous tasks for 12 hours after the first time you take terazosin or after your dose is increased, and until you know how this medication affects you.
you should know that terazosin may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking terazosin, when your dose is increased, or when treatment with terazosin is stopped for several days and then restarted. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If you experience these symptoms, sit or lie down. If these symptoms do not improve, call your doctor.
talk to your doctor about the risks and benefits of taking terazosin if you are 65 years of age or older. Older adults should not usually take terazosin to treat high blood pressure, because it is not as safe or effective as other medications that can be used to treat the same condition.

Terazosin side effects

Terazosin may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section are severe or do not go away:

weakness
tiredness
stuffy or runny nose
back pain
nausea
weight gain
decreased sexual ability
blurred vision
swelling of the hands, feet, ankles, or lower legs
pain, burning, numbness, or tingling in the hands or feet

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or seek emergency medical treatment:

hives
rash
itching
shortness of breath
rapid, pounding, or irregular heartbeat
painful erection of the penis that lasts for hours

Symptoms of overdose may include the following:

dizziness
lightheadedness
fainting
blurred vision

Terazosin may cause other side effects. Call your doctor if you have any unusual problems while taking terazosin.

Alpha blockers uses

Doctors prescribe alpha blockers to prevent, treat or improve symptoms mainly in these conditions:

High blood pressure (hypertension)
BPH (benign prostatic hyperplasia) or enlarged prostate

Though alpha blockers are commonly used to treat high blood pressure, they’re typically not the first treatment option. Instead, they’re used in combination with other drugs, such as diuretics, when your high blood pressure is difficult to control.

Alpha blockers side effects

Some alpha blockers might have what’s called a “first-dose effect.” When you start taking an alpha blocker, you might develop pronounced low blood pressure and dizziness, which can make you faint when you rise from a sitting or lying position. As a result, the first dose is often taken at bedtime.

Other side effects might include:

Headache
Pounding heartbeat
Weakness
Dizziness
Weight gain

On the positive side, alpha blockers might decrease low-density lipoprotein (LDL) cholesterol (the “bad” cholesterol).

Alpha blockers can increase or decrease the effects of other medications you take. Before taking an alpha blocker, be sure your doctor knows about other medications you take, such as beta blockers, calcium channel blockers or medications for erectile dysfunction.

Some research has found that long-term use of some alpha blockers can increase the risk of heart failure. More research is needed to confirm this finding.

Alpha blockers vs Beta blockers

Beta receptors exist throughout your body in three distinct forms: beta-1 (B1), beta-2 (B2), beta-3 (B3) ¹. Beta-1 receptors mediate cardiac activity and associated cardiovascular markers. Beta-2 receptors control various aspects of metabolic activity and induce smooth muscle relaxation. Beta 3 receptors induce the breakdown of fat cells and are less clinically relevant. Blockage of these receptors with beta-blockers is used to treat a broad range of illnesses ².

Beta blockers are indicated and FDA approved for the treatment of tachycardia, hypertension, myocardial infarction, congestive heart failure, cardiac arrhythmia, angina, hyperthyroidism, essential tremor, aortic dissection, portal hypertension, glaucoma, migraine prophylaxis, and other conditions. It is also used to treat less common conditions such as long QT syndrome and hypertrophic obstructive cardiomyopathy. Beta blockers are available in three main forms: oral, intravenous, and ophthalmic. In the outpatient setting, patients will be prescribed beta blockers in oral form. Emergency room and in-patient settings warrant intravenous usage, particularly for the acute control of pathology.

Congestive heart failure patients are treated with beta blockers if it’s in a compensated state. Specifically, the beta blockers bisoprolol, carvedilol, and metoprolol succinate are used.

Athletes and musicians use beta blockers for their anxiolytic effect as well as their negative effects on the sympathetic nervous system. They are not FDA approved for the treatment of anxiety-related disorders; however, they have a potent anxiolytic effect. Combined with a reduction in tremor, they can lead to improved accuracy in sports such as archery and improvement in stage performance.

Beta blockers are available in oral, intravenous, or ophthalmic form and can be injected intramuscularly.

Dosages are available in various ranges, depending on the specific medication.

Heart rate and blood pressure should be monitored while using beta blockers. Some patients should also be monitored for electrocardiogram (ECG) changes.

Beta blockers mechanism of action

There are two main classes of beta receptors: B1 and B2. Beta-3 receptors also exist. Two neurotransmitters, epinephrine, and norepinephrine, bind to B1 receptors and increase cardiac automaticity as well as conduction velocity. B1 receptors also induce renin release, and this leads to an increase in blood pressure. Binding to B2 receptors causes relaxation of the smooth muscles along with increased metabolic effects such as glycogenolysis. Some beta blockers also bind to alpha receptors to some degree. This allows them to induce a different clinical outcome when used in certain settings.

Once beta blockers bind to the B1 and B2 receptors, they inhibit these effects. Therefore, the chronotropic and inotropic effects on the heart are inhibited and the heart rate slows down. Beta blockers also decrease blood pressure via several theoretical mechanisms, including decreased renin and reduced cardiac output. The negative chronotropic and inotropic effects lead to a decreased oxygen demand; that is how angina improves after beta-blocker usage. These medications also prolong the atrial refractory periods and have a potent antiarrhythmic effect.

Beta blockers are classified as non-selective and beta-1 selective. There also exists B2 selective and B3 selective medications, neither has a known clinical purpose. Non-selective agents bind to both B1 and B2 receptors, antagonize them, and induce antagonizing effects via both receptors. Examples include propranolol, carvedilol, sotalol, and labetalol. B1 selective beta blockers only bind to the B1 receptors. They are cardio-selective. Examples include atenolol, bisoprolol, metoprolol, and esmolol ³.

Beta blockers lower the secretion of melatonin and hence may cause insomnia and sleep changes in some patients ⁴.

Alpha-1 receptors induce vasoconstriction and increased cardiac chronotropy. This means agonism at the alpha-1 receptors leads to a higher blood pressure and a higher heart rate. In contrast, antagonism at the alpha-1 receptor leads to vasodilation and negative chronotropy which leads to a lower blood pressure and lower heart rate. Some beta blockers, such as carvedilol, labetalol, and bucindolol, have additional alpha-1 receptor blockage activity in addition to their non-selective beta receptor blockage. This property is clinically useful because beta blockers that also block the alpha-1 receptor have a greater clinical effect on treating hypertension ⁵.

Beta blockers contraindications

Traditionally, beta blockers have been considered to be contraindicated in asthmatic patients. However, recommendations have aligned for allowing cardio-selective beta blockers, also known as B1 selective, in asthmatics but not non-selective beta blockers.

Beta blockers should not be used in patients who have cocaine-induced coronary vasospasm. There is a significant risk of unopposed alpha receptor activity which would worsen the vasospasm. Agonist activity at the alpha receptor leads to increased vasoconstriction and increased cardiac chronotropy ⁶.

Patients who have either acute or chronic bradycardia and/or hypotension are relatively contraindicated when it comes to beta-blocker usage.

Specific beta blockers are contraindicated depending on the patient’s past medical history. Patients diagnosed with long QT syndrome or who have had torsades de pointes in the past should not use the drug sotalol. Patients with Raynaud phenomenon should avoid beta blockers due to the risk of exacerbation ⁷.

Beta blockers side effects

Beta receptors are found all over the body and induce a broad range of physiologic effects. Blockage of these receptors with beta-blocker medications can lead to many adverse effects. Bradycardia and hypotension are two adverse effects that may be commonly seen. Fatigue, dizziness, nausea, and constipation are also commonly reported. Some patients report sexual dysfunction and erectile dysfunction.

Less commonly, bronchospasm is seen in patients on beta blockers. Asthmatic patients are at a higher risk ⁸. Patients with Raynaud syndrome are also at risk of exacerbation. Beta blockers can induce both hypoglycemia and mask the hemodynamic signs usually seen in a hypoglycemic patient, such as tachycardia.

Some patients report insomnia, sleep changes and nightmares while using beta blockers. This effect is more pronounced with beta blockers that can cross the blood-brain barrier.

Carvedilol may increase edema in some patients ⁹.

Sotalol blocks the potassium channels in the heart and thereby induces QT prolongation. It increases the risk of torsades de pointes ¹⁰.

All beta blockers, especially in patients with cardiac risk factors, carry a risk of heart block.

The antidote for beta-blocker overdose is glucagon. It is especially useful in beta-blocker-induced cardiotoxicity. The second line of treatment is cardiac pacing if glucagon fails.

References

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Pham D, Addison D, Kayani W, Misra A, Jneid H, Resar J, Lakkis N, Alam M. Outcomes of beta blocker use in cocaine-associated chest pain: a meta-analysis. Emerg Med J. 2018 Sep;35(9):559-563
De Vecchis R, Ariano C, Di Biase G, Noutsias M. Acquired drug-induced long QTc: new insights coming from a retrospective study. Eur. J. Clin. Pharmacol. 2018 Dec;74(12):1645-1651
Marques de Mello L, Cruz ÁA. A proposed scheme to cope with comorbidities in asthma. Pulm Pharmacol Ther. 2018 Oct;52:41-51
Soma K, Yao A, Saito A, Inaba T, Ishikawa Y, Hirata Y, Komuro I. Regular Treatment Strategy with a Large Amount of Carvedilol for Heart Failure Improves Biventricular Systolic Failure in a Patient with Repaired Tetralogy of Fallot. Int Heart J. 2018 Sep 26;59(5):1169-1173
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Alpha blockers

What are alpha blockers