Back pain after taking tadalafil may be caused by the side effects of the drug, which can usually be relieved on its own within 48 hours. Tadalafil is mainly used for the treatment of erectile dysfunction, taking tadalafil 12 to 24 hours may experience back pain, myalgia and other adverse reactions, usually relieved within 48 hours. Adverse reactions such as headache, nasopharyngitis, dyspepsia, and viral gastroenteritis may also occur with tadalafil. The drug is contraindicated in people who are allergic to nitrates or tadalafil and who are taking guanylate cyclase stimulators. Tadalafil is not suitable for pregnant women, lactating women, pediatric patients under 18 years of age. It is recommended that the drug is taken under medical supervision.