Never use with nitrate medicines (such as those for chest pain) or amyl nitrite ("poppers"). The combination can cause a dangerous drop in blood pressure. Check with your doctor first if you have heart disease, recent heart attack or stroke, very low or high blood pressure, or serious liver or kidney problems. Common side effects include headache, facial flushing, indigestion and a blocked nose. Seek urgent medical help for chest pain, sudden vision or hearing loss, or an erection lasting more than 4 hours. Avoid grapefruit juice and limit alcohol, which can reduce effectiveness. Intended for adult men only. Store below 30°C. This product information is for general guidance only and does not replace professional medical advice. Always consult a qualified healthcare provider before starting any new medication or supplement. Keep all medicines out of reach of children.