Viagra, the brand of sildenafil, is a prescription medication classified as a phosphodiesterase-5 (PDE-5) enzyme inhibitor. It is used in the treatment of erectile dysfunction in men. Viagra works by enhancing the response to sexual stimuli in the body. This leads to an erection of the penis when arousal occurs; the drug does not directly cause erection. Like all medications, Viagra exhibits several side effects.
Headache
Headache is a common side effect seen with the use of Viagra. The "Drug Information Handbook" reports that up to 46 percent of users experience a headache, which should diminish with continued use of the drug. If the headache becomes persistent, inform a health care professional. A pharmacist or physician may be able to suggest a pain reliever, such as acetaminophen (Tylenol), or determine if further medical attention is necessary.
Indigestion
Viagra may cause indigestion in about 15 percent on users. Taking the medication with a meal may help alleviate this side effect. If nausea occurs, the patient should try chewing gum or suck on lozenges for relief. If indigestion becomes severe or persistent, the patient should inform a health care provider and seek medical help.
Effects on Vision
Viagra can affect vision when doses larger than 100 mg are used. "Sildenafil causes increased sensitivity to light, blurred vision or loss of blue-green color discrimination in 3 percent to 10 percent of patients," says "Pharmacotherapy: A Pathophysiologic Approach." The effect that leads to enhanced response to sexual stimuli also affects other chemicals in the body that are found in the eyes, leading to these side effects. Vision changes associated with Viagra are mild and reversible, and do not pose a major concern. However, caution is recommended by those who require sharp vision, such as airplane pilots, who need to see blue and green landing lights while landing planes.
Dizziness
Dizziness is another side effect seen with the use of Viagra. About 5 percent of individuals may experience this. It may also be a symptom of hypotension, which is a drop in blood pressure. "Pharmacotherapy: A Pathophysiologic Approach" explains that although many patients do not show symptoms, those who are on multiple medications for treatment of high blood pressure or chest pain may feel faint or dizzy. The patient should be careful when driving or performing activities that require alertness. If severe dizziness occurs, the patient should receive immediate medical care.
Flushing
Flushing is a side effect that may occur in about 10 percent of users. Flushing is characterized by redness and heat in the face and hands, due to increased blood flow within the body. It is not a harmful effect and does not require emergency care.
Hearing Loss
Hearing loss is another adverse reaction that may occur with the use of Viagra. According to Pfizer, a sudden decrease or loss of hearing has occurred while the patients were taking the medication. Although it is not possible to establish a direct link between hearing changes and the PDE-5 inhibitors, such as Viagra, the manufacturer's label includes a revised Precaution and Adverse Drug Reaction section. The new label revisions warn the patient to stop taking the medication and to seek medical care if hearing decreases.
References
- "Drug Information Handbook (15th Edition)"; Charles Lacy, Lora Armstrong et al; 2007
- "Pharmacotherapy: A Pathophysiologic Approach"; Joseph Dipiro, Robert Talbert et al; 2008
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