Sildenafil improves blood flow to the penis when sexually excited. It does this by causing relaxation of local blood vessels, thus alleviating Erectile Dysfunction, or male impotence.
Tablets taken once per day. Treatment starts at short notice (2 days before trip) and stops 1 week after the trip (compared to 4 weeks for other anti-malarials). Malarone is notable for having far fewer side effects than other, older malaria drugs.