Sildenafil citrate tablets work half an hour to two hours after taking them on an empty stomach, and the time varies from person to person depending on their sensitivity to the drug.
Sildenafil citrate can treat erectile dysfunction and can also treat pulmonary hypertension. For the treatment of erectile dysfunction, it works for half an hour to two hours after taking it on an empty stomach, so it needs to be taken orally before sex and its effect lasts for about four hours.
The drug is contraindicated in patients who are allergic to sildenafil citrate or are taking nitrates or nitrites. Taking the drug may cause headache, flushing, indigestion, nasal congestion and other adverse reactions.
The exact dosage of the drug needs to be directed by a medical professional. The drug must be taken under the guidance of a doctor to avoid adverse reactions affecting health.