Sildenafil Side Effects

Brand Names: Revatio, Viagra

Please note - some side effects for Sildenafil may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Sildenafil - for the Consumer

Sildenafil

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Sildenafil:

Diarrhea; dizziness; flushing; headache; heartburn; stuffy nose; upset stomach.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; fainting; fast or irregular heartbeat; memory loss; numbness of an arm or leg; one-sided weakness; painful or prolonged erection; ringing in the ears; seizure; severe or persistent dizziness; severe or persistent vision changes; sudden decrease or loss of hearing; sudden decrease or loss of vision in one or both eyes.

Side Effects by Body System

General

Prior to approval by the FDA, use of sildenafil was evaluated in over 3,700 patients who ranged from 19 to 87 years of age. Over 550 patients were treated for at least 1 year. In placebo-controlled trials, the rate of discontinuation of therapy due to adverse events associated with sildenafil averaged 2.5%, which was not significantly different compared with placebo (2.3%). The incidence of side effects has been dose-dependent.

Nervous system

Nervous system side effects have included headache, observed in up to 16% of patients. Other nervous system side effects have included dizziness in 2%, and, in less than 2%: ataxia, hypertonia, neuralgia, neuropathy, paresthesias, tremor, vertigo, depression, insomnia, somnolence, abnormal dreams, decreased reflexes, and hypesthesia. There have been case reports of transient global amnesia and tonic-clonic seizures. Post marketing experience has included reports of anxiety, seizure and seizure recurrence.

Cardiovascular

Cardiovascular side effects have included flushing (vasodilation) in 10% and dizziness in 2% of patients. Consistent with its known effects on the nitric oxide/cGMP pathway, use of sildenafil has been shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are concurrently taking organic nitrates is considered contraindicated. The following cardiovascular side effects have been associated with the use of sildenafil in less than 2% of patients: angina pectoris, AV block, migraine, syncope, tachycardia, palpitation, hypotension, postural hypotension, myocardial ischemia, cerebral thrombosis, cardiac arrest, heart failure, abnormal electrocardiogram, chest pain, and cardiomyopathy.

Postmarketing studies have reported serious cardiovascular events, including myocardial infarction, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, and hypertension in temporal association with the use of sildenafil. Most patients had preexisting cardiovascular risk factors. Many of these events were reported to occur during or shortly after sexual activity, and a few were reported to occur shortly after the use of sildenafil without sexual activity. Others were reported to have occurred hours to days after the use of sildenafil and sexual activity. It has not been determined whether these events are related directly to sildenafil, to sexual activity, to the patient's underlying cardiovascular disease, to a combination of these factors, or to other factors.

Gastrointestinal

Gastrointestinal side effects have included dyspepsia (7%) and diarrhea (3%). Less common gastrointestinal side effects have included abdominal pain, vomiting, glossitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, dry mouth, abnormal liver function tests, rectal hemorrhage, and gingivitis. Inhibition of contractile activity of the esophagus has been reported in patients receiving sildenafil who have idiopathic achalasia.

Results from a study of patients with idiopathic achalasia given sildenafil therapy showed inhibition of contractile activity of the esophageal musculature resulting in decreased lower esophageal sphincter tone and residual pressure as well as contraction amplitude.

Respiratory

Respiratory system side effects have included nasal congestion (4%). Other respiratory system side effects have included wheezing, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, increased sputum production, and cough.

Genitourinary

Genitourinary side effects have included urinary tract infection in 3% of patients. Less commonly, occurring in less than 2% of patients, cystitis, nocturia, urinary frequency, breast enlargement, urinary incontinence, abnormal ejaculation, genital edema, and anorgasmia have been reported. Prolonged erection greater than 4 hours and priapism (painful erections greater than 6 hours in duration) have been reported infrequently since market approval of sildenafil. In the event of an erection that persists longer than 4 hours, the patient should seek immediate medical assistance. If priapism is not treated immediately, penile tissue damage and permanent loss of potency could result. Acute priapism associated with the use of sildenafil in a patient with sickle cell trait has been reported.

Ocular

Sildenafil is selective for phosphodiesterase-5 (PDE5). It has lesser affinity for other PDE isoenzymes, one of which is PDE6, an enzyme found in the retina. This lower selectivity is thought to be the basis for abnormalities related to color vision observed with higher doses or plasma levels.

Nonarteritic anterior ischemic optic neuropathy developed in one eye within minutes to hours after ingestion of sildenafil. Four of the five patients had no vascular risk factors for ischemic optic neuropathy.

Ocular side effects have included mild and transient blue or colored-tinged vision, sometimes associated with photosensitivity or blurred vision. Less common ocular side effects (less than 2% of patients) have included mydriasis, conjunctivitis, photophobia, tinnitus, eye pain, deafness, ear pain, eye hemorrhage, cataract, and dry eyes. Several cases of optic neuropathy have been associated with sildenafil use.

Dermatologic

Dermatologic side effect have included rash which was reported in at least 2% of patients. Other dermatologic side effects have included urticaria, herpes simplex, pruritus, sweating, skin ulcer, contact dermatitis, and exfoliative dermatitis.

Hematologic

Hematologic side effects have included anemia and leukopenia.

Metabolic

Metabolic side effects have included thirst, peripheral and general edema, gout, hyperglycemia, hypoglycemia (including hypoglycemia reactions), and hypernatremia.

Other

Other side effects have included facial edema, shock, asthenia, pain, chills, and accidental falls and injuries.

Musculoskeletal

Musculoskeletal side effects have included arthritis, arthrosis, myalgia, tendon rupture, tenosynovitis, bone pain, myasthenia, and synovitis.

Psychiatric

Psychiatric side effects have included anecdotal reports and case studies of psychological disturbances and aggressive behavior.

Other

Other side effects have included cases of sudden decrease or loss of hearing reported post-marketing in temporal association with the use of PDE5 inhibitors, including sildenafil. In some cases, medical conditions and other factors were reported that may have also played a role in the otologic adverse events. In many cases, medical follow-up information was limited. It is not possible to determine whether these reported events are related directly to the use of sildenafil, to the patient's underlying risk factors for hearing loss, a combination of these factors, or to other factors.

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