Malegra FXT is a combination medication containing sildenafil (for erectile dysfunction) and fluoxetine (for premature *****). While sildenafil generally targets blood vessels, back pain is a known but uncommon side effect of PDE-5 inhibitors like sildenafil. Here’s when it may occur: Timing: Usually 12–24 hours after taking the dose, though it can appear sooner in some men. Often mild to moderate and temporary, resolving within 48 hours. Why it happens: Sildenafil can relax smooth muscles and affect blood flow, sometimes causing muscle or joint discomfort, including in the lower back. Dehydration or strenuous activity around the time of taking the drug can increase the likelihood of back pain. Risk factors: Higher doses of sildenafil (like in Malegra FXT) Pre-existing back or musculoskeletal issues Age-related muscle stiffness Management: Mild back pain usually resolves without treatment. Over-the-counter pain relief (like acetaminophen or ibuprofen) can help if approved by a doctor. Staying hydrated and stretching lightly may reduce discomfort. Important: If back pain is severe, persistent, or accompanied by other symptoms (like chest pain, vision changes, or numbness), stop the medication and seek medical attention immediately. If you want, I can make a quick guide of all Malegra variants and their common side effects, including back pain and timing, so you can see which formulations are more likely to cause it.