COWS Calculator: Opioid Withdrawal Severity

What it measures

The Clinical Opiate Withdrawal Scale (COWS; Wesson and Ling, 2003) is an 11-item clinician-administered instrument that rates common signs and symptoms of opioid withdrawal. It is used to quantify withdrawal severity, follow its course over repeated ratings, and guide the timing of buprenorphine induction. Each item is rated by its apparent relationship to withdrawal, so a fast pulse from recent exertion, for example, is not counted.

Items and scoring

The items are resting pulse rate, sweating, restlessness, pupil size, bone or joint aches, runny nose or tearing, GI upset, tremor, yawning, anxiety or irritability, and gooseflesh skin. Item weights differ: pulse, sweating, aches, rhinorrhea and tearing, tremor, yawning and anxiety score up to 4; restlessness, pupil size, GI upset and gooseflesh score up to 5. Each item shows its anchor descriptions and observation instructions (for example, pulse measured after one minute sitting or lying). The total is the sum, from 0 to 48.

Total	Band
0–4	No significant withdrawal
5–12	Mild withdrawal
13–24	Moderate withdrawal
25–36	Moderately severe withdrawal
37–48	Severe withdrawal

Unanswered items count as 0. Until all 11 items are rated, the tool labels the result an incomplete partial score and does not interpret it, because the total may underestimate severity.

Interpreting the result

A score of about 8 or more with short-acting opioids, or about 12–13 or more with long-acting opioids such as methadone, is traditionally used as the threshold for starting buprenorphine to reduce the risk of precipitated withdrawal. Each band comes with guidance text. With fentanyl exposure, the tool notes that withdrawal can be delayed and that low-dose (micro) or high-dose induction may be considered per protocol. The moderately severe band prompts monitoring for dehydration and electrolyte disturbance; the severe band suggests considering a higher level of care. Interpretation should always be combined with clinical judgment, last-use history and local protocol.

What the report includes

The copied plain-text report contains the date, an optional reason for the assessment, the total out of 48, the severity band (or an incomplete flag with the number of items rated), each item score against its maximum, the band cut-offs, the clinical interpretation text, and the Wesson and Ling citation. A live item-score grid is shown on screen as you rate.