| System | Manifestations |
| Pulmonary | Respiratory depression, noncardiogenic pulmonary edema |
| Cardiovascular | Orthostatic hypotension, peripheral vasodilation, dysrhythmias |
| Neurologic | Analgesia, euphoria, dysphoria, miosis, mydriasis, seizures |
| Gastrointestinal | Nausea, vomiting, constipation |
| Dermatologic | Flushing, pruritus |
| Reproductive | Amenorrhea, anovulation |
