Malegra 120 should not be taken again within 24 hours. Malegra 120 contains sildenafil, a medicine used for erectile dysfunction, and 120 mg is higher than the usual recommended maximum single dose of 100 mg in 24 hours. If you have already taken one 120 mg tablet: Do not take another for at least 24 hours, and check with a doctor before taking it again because this dose is higher than recommended. If the first dose did not work: Do not take an extra tablet to try to improve the effect. Sildenafil may take around 30–60 minutes to work. If you take nitrates for chest pain, such as nitroglycerin, do not use sildenafil because the combination can cause a dangerous drop in blood pressure. - Seek urgent medical help if you develop chest pain, fainting, sudden vision or hearing changes, or an erection lasting more than 4 hours. The standard sildenafil guidance recommends no more than one dose per day and a maximum of 100 mg per dose.