Sildenafil Citrate: Precautions
|
|
Viagra is not labeled or approved for use by women or children, or by men without erectile dysfunction. The medication may also be contraindicated (not recommended for use) in patients with certain medical conditions.
Because sexual activity can stress the heart, men who have heart problems should check with their physician to see if sexual activity is recommended. Viagra may trigger temporary hypotension (low blood pressure) and is known to increase cardiovascular nerve activity, so it is prescribed with caution in men with a history of heart attack, artherosclerosis, angina, arrhythmia, and chronic low blood pressure problems. However, a study published in the March 15, 2001, British Medical Journal found no evidence that the drug causes a higher incidence of heart attack. Further long-term studies are needed to determine the full implications of sildenafil citrate on heart disease.
Anyone experiencing cardiovascular symptoms such as dizziness, chest or arm pain, and nausea when participating in sexual activity after taking Viagra should stop the encounter. They should also not take Viagra again until they have discussed the episode with their healthcare provider.
It is recommended that men with kidney or liver impairments, and men over age 65, start at the lowest possible dosage of Viagra (25 mg). Clinical studies have shown that the drug builds up in the plasma of these patients to a concentration that is three to eight times higher than normal. Caution is also recommended in prescribing the drug to individuals with retinitis pigmentosa, a rare genetic eye disorder. Viagra should not be taken more than once per day by anyone.
Viagra has not been studied for use on patients with stomach ulcers and bleeding disorders, and its safety in these individuals is unknown. Men who have either of these conditions should let their physician know before taking Viagra. It should also be used with caution in men with misshapen or deformed penises, such as those with Peyronie's disease, cavernosal fibrosis, or with angulation of the penis.
Men who take medications containing nitrates (e.g., nitroglycerin, isosorbide mononitrate, isosorbide dinitrate) should never take Viagra, as the interaction between the two drugs may cause a dramatic drop in blood pressure, and possibly trigger a heart attack or stroke. This includes illegal recreational drugs such as amyl nitrates (also known as poppers).
Viagra may also interact with other prescription and over-the-counter (OTC) medications, either magnifying or diluting the intended therapeutic effects of one or both drugs. Some drugs that have a known interaction with Viagra include the protease inhibitor ritonavir and the antibiotic erythromycin. For this reason, it is critical that men who are prescribed Viagra let their healthcare providers know all the medications they are taking.
Other medications and therapies for erectile dysfunction, including vacuum or pump devices, drug injections (Caverject), and urethral suppositories (MUSE), should never be used in conjunction with Viagra.
— Paula Anne Ford-Martin
