Nausea, vomiting, diarrhea (antibiotic-associated colitis), abdominal pain, disturbance in liver function tests, thrombocytopenia (reduction in partial thromboplastin time), +ve Coombs' test, eosinophilia, leukopenia, neutropenia, headache, paresthesia, hypersensitivity reactions (including rash, pruritus, urticaria, angioedema & anaphylaxis), convulsions, Stevens-Johnson syndrome, toxic epidermal necrolysis, local reactions (including pain & thrombophlebitis at inj site).