COWS Opioid Withdrawal
Clinical Opiate Withdrawal Scale for quantitative opioid withdrawal rating (11 items, max 48).
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Minimal or no withdrawal (score 0–4). Buprenorphine induction is not indicated.
- Evidence grade
- A
What it is and when to use it
The Clinical Opiate Withdrawal Scale (COWS) is an 11-item clinician-administered instrument for objective opioid withdrawal scoring.
How to interpret it
Scores 5–12: Mild withdrawal; 13–24: Moderate withdrawal; 25–36: Moderately severe withdrawal; >36: Severe withdrawal.
Limitations and when not to use it
Buprenorphine induction before reaching a COWS score of at least 12–13 may cause severe precipitated withdrawal.
Frequently asked questions
- Why is COWS timing crucial for buprenorphine?
- Buprenorphine is a partial agonist with high receptor affinity. Initiating it too early displaces full opioids and precipitates acute severe withdrawal.
Formulas and cut-offs are from the original authors of each score; see the references.
Last reviewed: June 2026
References
- Wesson DR, Ling W. The Clinical Opiate Withdrawal Scale (COWS). J Psychoactive Drugs. 2003;35(2):253-259. PMID:12924748