Flomax and Viagra for Benign Prostatic Hyperplasia Treatment

John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha’s educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

  • Both Flomax (generic name tamsulosin) and Viagra (generic name sildenafil) are medications prescribed to treat symptoms of benign prostatic hyperplasia (BPH), which causes an enlarged prostate.
  • Flomax is an alpha-blocker prescribed to treat difficulty urinating a symptom of BPH.
  • Viagra is a phosphodiesterase inhibitor (PDE-5 inhibitor) prescribed to treat impotence, another symptom of BPH.
  • Both drugs are available in generic form.
  • Because Flomax and Viagra are different types of drugs, most of the side effects are different.
  • Common side effects of Flomax include anemia (decreased red blood cells), decreased white blood cells, nausea, vomiting, abnormal taste, increased triglycerides, and weakness.
  • Common side effects of Viagra include facial flushing, headaches, stomach pain, stuffy nose, nausea, dizziness, rash, urinary tract infections (UTIs) diarrhea, and an inability to differentiate between the colors green and blue.
  • One similar serious side effect of both Flomax and Viagra is prolonged erections lasting more than 4 hours (priapism).

Flomax (tamsulosin) is an oral drug prescribed to treat men who are having difficulty urinating because of an enlarged prostate gland due to benign prostatic hyperplasia (BPH). Difficulty urinating is caused only in part by the enlarged prostate. The other cause of the difficulty is the muscle cells tightening around the bladder outlet. Flomax helps the muscles relax, which results in a decrease in obstruction to the flow of urine.

Viagra (sildenafil) is used for treating impotence (or erectile dysfunction, ED, the inability to attain or maintain a penile erection). It is in a class of drugs called phosphodiesterase inhibitors (PDE-5 inhibitors) that also includes tadalafil (Cialis), vardenafil (Levitra, Staxyn ODT), and avanafil (Stendra). It works by increasing blood flow to the penis, enabling a man to get and keep an erection.

What are the side effects of Flomax and Viagra?

Flomax side effects

The most common adverse effects of Flomax include:

Other side effects include:

More serious side effects that have been observed in male patients during treatment with Flomax include:

  • Orthostatic hypotension (low blood pressure when rising from sitting or lying down position)
  • Priapism (prolonged erection)
  • An eye problem called intraoperative floppy iris syndrome (IFIS)

Viagra side effects

Approximately 15% of males taking Viagra experience side effects.

The most common side effects include:

What is the dosage of Flomax and Viagra?

Flomax dosage instructions

  • The recommended starting dose is 0.4 once daily about 30 minutes after the same mealtime each day.
  • When taken on an empty stomach, more of the medication is absorbed.
  • This could cause a greater effect and potentially a drop in blood pressure.
  • The dose may be increased to 0.8 mg once daily after 2 to 4 weeks if the response is not adequate.
  • The capsules should not be crushed, chewed, or opened.

Viagra dosage instructions

  • The usual recommended dose is 25 to 100 mg 1 hour before sexual activity.
  • The maximum dose is 100 mg daily.
  • The elderly (over 65 years of age) should start at 25 mg before sexual activity.
  • Sildenafil is rapidly absorbed. Maximum observed plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state. When sildenafil is taken with a high fat meal, the rate of absorption is reduced, with an average delay in the time to maximal concentration of 1 hour.

What are the drug interactions of Flomax and Viagra?

Flomax drug interactions

The elimination of Flomax from the body may be reduced by:

Reduced elimination may lead to increased side effects of Flomax. PDE-5 inhibitors (for example, vardenafil [Levitra, Staxyn], Adcirca, sildenafil [Viagra, Revatio], tadalafil [Cialis]) add to the blood pressure lowering effects of Flomax and may result in severe blood pressure reduction.

Viagra drug interactions

Viagra increases the effects of the blood pressure lowering medications. It also increases the blood pressure lowering effects of nitrates, for example, isosorbide dinitrate (Isordil), isosorbide mononitrate (Imdur, Ismo, Monoket), nitroglycerin (Nitro-Dur, Transderm-Nitro) that are used primarily for treating angina. Patients taking nitrates should not receive Viagra.

Cimetidine (Tagamet), erythromycin, ketoconazole (Nizoral), itraconazole (Sporanox), atazanavir (Reyataz), and mibefradil (Posicor) can cause marked increases in the amount of Viagra in the body. Patients taking these medications should be observed carefully if sildenafil is used.

Patients should not combine Viagra with other PDE5 inhibitors (for example, vardenafil [Levitra], tadalafil [Cialis]).

It is expected that rifampin will decrease blood levels of Viagra and probably reduce its effectiveness.
Flomax (brand name tamsulosin) is a medication doctors prescribe to males who have an enlarged prostate gland and who are having difficulty urinating due to a condition called benign prostatic hyperplasia (BPH). Flomax blocks chemicals in the muscle cells of the penis to relax, which results in the ability to urinate. Viagra (brand name sildenafil) is a medication doctors prescribe to men who are having problems getting and sustaining an erection (erectile dysfunction, ED, impotence). Viagra works by increasing blood flow to the penis, which allows for a man to get and keep an erection.

Flomax does have serious side effects that include a prolonged erection, intraoperative floppy iris syndrome (an eye problem), and orthostatic hypotension. Click here for dosage and drug interactions for Flomax.

Click here for dosage and drug interaction information for Viagra.

Multimedia: Slideshows, Images & Quizzes

Benign Prostatic Hyperplasia (Enlarged Prostate) Quiz

Take the Enlarge Prostate Quiz and challenge your knowledge of prostate problems. Learn causes, symptoms, treatments, and.

Picture of Prostate Gland

A gland within the male reproductive system that is located just below the bladder. See a picture of Prostate Gland and learn.

Picture of Prostate

Side View of the Prostate. The prostate is a walnut-sized gland located between the bladder and the penis. See a picture of the.

Enlarged Prostate (BPH) Symptoms, Diagnosis, Treatment

Benign Prostatic Hyperplasia (BPH) is a condition cause by an enlarged prostate. Get more information on how an enlarged prostate.

Related Disease Conditions

Enlarged Prostate (BPH, Benign Prostatic Hyperplasia)

Benign prostatic hyperplasia (BPH or enlarged prostate) is very common in men over 50 years of age. Half of all men over the.

Prostate Problem Warning Signs

Prostate problems are common in men over the age of 50. Benign prostatic hyperplasia, acute bacterial prostatis, chronic.

Mental Health

Mental health is an optimal way of thinking, relating to others, and feeling. All of the diagnosable mental disorders fall under.

Urinary Retention

Urinary retention (inability to urinate) may be caused by nerve disease, spinal cord injury, prostate enlargement, infection.

Prostatitis vs. BPH (Enlarged Prostate) Differences and Similarities

Prostatitis and BPH (benign prostatic hyperplasia, enlarged prostate gland) are both conditions of the prostate gland. There.

Treatment & Diagnosis

Medications & Supplements

Latest Mental Health News

Daily Health News

Trending on MedicineNet

Health Solutions From Our Sponsors

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Featured Slideshows

Heat Rash How Do You Get Rid of It?

Skin Problems 15 Surprising Skin Problems as You Age
Digestive Disorders What Your Poop Says About Your Health