<s>[INST] Hi doctor, I am 21 years old. Does tablet Megalis 10 mg give priapism? Will it show any harsh side effects? [/INST] Hi. The drug in that tablet is Tadalafil. It is used in erectile dysfunction (impotence), enlarged prostate gland, sometimes in pulmonary arterial hypertension. Priapism is considered rare during this treatment. Some significant side effects are dizziness, confusion, fainting, vomiting, and ear problems. This tablet is taken only during night time. You should avoid driving or any work at high altitudes after taking this tablet. If the erection occurs up to four hours, and if it is painful, kindly do not retake the tablet. Consult a nearby doctor as soon as possible. For more information consult a family physician online --> </s>