Maxon Forte (Sildenafil)

Sildenafil is a phosphodiesterase type 5 inhibitor used to treat conditions related to impaired blood flow.

• Erectile dysfunction: improves ability to achieve and maintain an erection in response to sexual stimulation.
• Pulmonary hypertension: helps lower pulmonary arterial pressure and enhances exercise capacity in patients with pulmonary hypertension.
• Diabetes‑related erectile dysfunction: supports erectile function in men whose ED is associated with diabetes.

• Sildenafil selectively inhibits the enzyme phosphodiesterase type 5 (PDE5) in smooth muscle cells of the corpus cavernosum and pulmonary vasculature. By blocking PDE5, it prevents the breakdown of cyclic guanosine monophosphate (cGMP), leading to accumulation of cGMP, smooth‑muscle relaxation, vasodilation, and increased blood flow to the target tissues. The elevated cGMP levels also enhance nitric oxide signaling, further promoting vasodilation in the penile and pulmonary arteries.

Sildenafil may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Headache: mild to moderate pain often transient.
• Flushing: warmth and redness of the face or upper body.
• Dyspepsia: indigestion or upset stomach.
• Nasal congestion: stuffy nose.
• Visual disturbances: blurred vision or color tinge.
• Back pain: muscle aches in the lower back.

Serious or Rare Side Effects

• Priapism: prolonged erection lasting more than four hours.
• Sudden vision loss: abrupt loss of vision in one or both eyes.
• Sudden hearing loss: rapid decrease in hearing ability.
• Severe hypotension: marked drop in blood pressure.
• Cardiovascular events: heart attack or stroke in at‑risk patients.
• Anaphylactic reaction: severe allergic response requiring immediate medical care.

Before prescribing sildenafil, clinicians should consider several precautionary measures to ensure patient safety.

• Cardiovascular assessment: evaluate for recent myocardial infarction, unstable angina, or severe heart failure.
• Nitrate use: avoid concurrent use with nitrates due to risk of profound hypotension.
• Liver impairment: adjust use in patients with severe hepatic dysfunction.
• Alcohol consumption: limit excessive alcohol as it may increase hypotensive effects.
• Ocular conditions: use caution in patients with retinal disorders such as retinitis pigmentosa.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Sildenafil can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Nitrates (e.g., nitroglycerin): may cause dangerous drops in blood pressure.
• Guanylate cyclase stimulators (e.g., riociguat): additive vasodilatory effect leading to severe hypotension.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): increase sildenafil plasma concentrations.

Moderate Interactions (Monitor Closely)

• Alpha‑blockers (e.g., doxazosin): may cause additive blood pressure lowering.
• Antihypertensives (e.g., beta‑blockers): monitor for enhanced hypotensive response.
• CYP3A4 inducers (e.g., rifampin): may reduce sildenafil effectiveness.