Does Levitra have side-effects?
Those involved in the clinical trials reported mild / moderate side effects with the treatment, these mostly included headaches, flushing and rhinitis (nasal congestion).

Who should avoid taking Levitra?
Levitra should not be taken if you are taking nitrates or nitric oxide donors (these medications are used to treat angina or chest pain). It is also contraindicated in men whom sex is inadvisable and men older than 75 years old who concomitantly use potent CYP 3A4 inhibitors (such as ritonavir, indinavir, ketoconazole and itraconazole). The safety of Levitra has not been studied in these subgroups and should not take Levitra until further studies are available: severe hepatic (liver system) impairment, endstage renal disease requiring dialysis, hypotension, recent history of stroke or heart attack, unstable angina, and known hereditary retinal degenerative disorders.

Levitra drug interactions:
Tell your online doctor of all nonprescription and prescription medication you may use, especially any nitrate medications (e.g., nitroglycerin, isosorbide dinitrate), nitroprusside (any "nitric oxide donor" medicines), cimetidine, erythromycin, azole antifungals (e.g., itraconazole, ketoconazole), mibefradil, rifamycins (e.g., rifampin) or high blood pressure medicines.