Risks associated with oral diltiazem use: The therapeutic dose of diltiazem ranges from 120 mg to 480 mg per day. Common side effects of chronic diltiazem therapy include edema (2% to 15%), headache (5% to 12%), AV block (first degree 2% to 8%), bradycardia (2% to 6%), hypotension (2% to 4%), vasodilation (2% to 3%), extrasystoles (2%), flushing (1% to 2%), palpitation (1% to 2%), dizziness (3% to 10%), nervousness (2%), rash (1% to 4%), gout (1% to 2%), dyspepsia (1% to 6%), constipation (<2% to 4%), vomiting (2%), diarrhea (1% to 2%), weakness (1% to 4%), myalgia (2%), rhinitis (<2% to 10%), pharyngitis (2% to 6%), dyspnea (1% to 6%), bronchitis (1% to 4%), cough (≤3), and sinus congestion (1% to 2%). Rare (< 1%) side effects of diltiazem include an increase in alkaline phosphatase, allergic reaction, increase in liver transaminases, amblyopia, amnesia, arrhythmia, AV block (second or third degree), bundle branch block, heart failure, depression, dysgeusia, extrapyramidal symptoms, gingival hyperplasia, hemolytic anemia, petechiae, photosensitivity, Stevens-Johnson syndrome, syncope, tachycardia, thrombocytopenia, tremor, and toxic epidermal necrolysis.