How it's calculated
11 signs and symptoms of opioid withdrawal are each rated by clinical assessment within their own documented range (0-4 or 0-5 depending on the item), summing to a maximum total of 48.
Score interpretation
| COWS | Interpretation |
|---|---|
| 0–4 | No/minimal withdrawal |
| 5–12 | Mild withdrawal |
| 13–24 | Moderate withdrawal |
| 25–36 | Moderately severe withdrawal |
| >36 | Severe withdrawal |
Clinical use
- Commonly used to confirm a patient is in objective opioid withdrawal (often a score ≥8-12, depending on local protocol) before starting buprenorphine induction, since starting too early risks precipitating worse withdrawal.
- Also used to track withdrawal severity and response to treatment over time with serial reassessment.
- Relies on clinical observation of objective signs alongside patient-reported symptoms, distinguishing it from purely subjective withdrawal scales.
Frequently asked questions
What is COWS used for?
The Clinical Opiate Withdrawal Scale quantifies the severity of opioid withdrawal signs and symptoms, and is widely used to confirm objective withdrawal before starting buprenorphine induction.
Why does COWS matter for starting buprenorphine?
Starting buprenorphine too early, before a patient is in sufficient objective withdrawal, can precipitate a sudden, more severe withdrawal reaction because buprenorphine is a partial agonist that can displace full agonists from opioid receptors. Many protocols require a minimum COWS score (often around 8-12) before induction.
What is the maximum possible COWS score?
48 — the sum of the maximum points across all 11 items, though each item has a different maximum (4 or 5) rather than a uniform scale.
References
- Wesson DR, Ling W. The Clinical Opiate Withdrawal Scale (COWS). J Psychoactive Drugs. 2003;35:253-259.