Tadalafil tablets generally take effect about 30 minutes after the medication is administered, with the exact time of onset varying from person to person. Tadalafil Tablet is a cyclic guanosine monophosphate-specific phosphodiesterase 5 inhibitor indicated for the treatment of erectile dysfunction in men. The medication is generally recommended to be taken at least 30 minutes prior to sexual intercourse, and it will be effective when used for 30 minutes or more, but the exact time of onset of effect varies from person to person. Common adverse reactions after taking the drug include back pain, headache, myalgia, upper respiratory tract infection, cough, nasal congestion, dyspepsia, gastroesophageal reflux, and hypertension. The drug is contraindicated in people who are taking guanylate cyclase stimulators and nitrates, people with previous non-arteritic anterior ischemic optic neuropathy resulting in loss of vision on one side of the eye, people with an underlying risk of cardiac disease, and people who are allergic to the product. The specific use of drugs should be under the guidance of a specialist, should not be self-medication.