| Stage | Features |
| Stage I: Up to 8 hours | Fear of withdrawal, anxiety, drug craving |
| Stage II: 8-24 hours | Insomnia, restlessness, anxiety, yawning, stomach cramps, lacrimation, rhinorrhea, diaphoresis, mydriasis |
| Stage III: Up to 3 days | Vomiting, diarrhea, fever, chills, muscle spasms, tremor, tachycardia, piloerection, hypertension, seizures* |
