Flomax and Viagra for BPH Treatment Quick Comparison
- 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).
What is Flomax? What is Viagra?
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:
- Anemia (decreased red blood cells)
- Decreased white blood cells
- Nausea
- Vomiting
- Abnormal taste
- Increased triglycerides
- Weakness
Other side effects include:
- Low blood pressure
- Dizziness
- Fainting
- Headache
- Abdominal pain
- Weight loss
- Muscle pain
- Abnormal ejaculation
- Upper respiratory tract infections
- rash
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:
- facial flushing (1 in 10)
- headaches (1 in 6)
- stomach pain
- nasal congestion
- nausea
- dizziness
- rash
- urinary tract infections (UTIs)
- diarrhea
- an inability to differentiate between the colors green and blue
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:
- erythromycin,
- ketoconazole (Nizoral, Extina, Xolegel, Kuric),
- paroxetine (Paxil),
- cimetidine (Tagamet),
- ritonavir (Norvir),
- lopinavir, and
- other drugs that reduce the elimination of drugs by liver enzymes.
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.