Calculators / Substance use and withdrawal
COWS
Clinical Opiate Withdrawal Scale. Opioid withdrawal severity.
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The COWS calculator is in the Library.
Every rating scale calculator comes with the Library, along with the prescribing guides, medication handouts, DSM-5 criteria and sheets, and the Guide Builder.
Use it for
- Rating the severity of opioid withdrawal in an adult who has recently reduced or stopped opioids.
- Following withdrawal over time and documenting the trend.
- Helping to time buprenorphine induction, along with the history and the time since last use.
Do not use it for
- Diagnosing opioid use disorder. A person can have the disorder and no withdrawal at the time of rating.
- Rating signs that have another cause. Rate only what is apparently related to opioid withdrawal.
- Withdrawal from alcohol or sedatives. Use the CIWA-Ar for alcohol withdrawal and a benzodiazepine scale for sedatives.
Rate now, from observation and a few direct questions. Choose the number that best describes the person's signs or symptoms. Rate only the apparent relationship to opiate withdrawal: if the pulse is high because the person was jogging just before, the pulse does not add to the score.
COWS
Answer the questions to see the result.
This calculator adds up the score in your browser. Nothing you enter is stored or sent.
More about the COWS
About the COWSWhat it is and what it is for
The COWS is an 11-item scale that a clinician uses to rate the signs and symptoms of opioid withdrawal at a given moment. Wesson and Ling published it in 2003. Most items are rated from observation, such as pulse, pupils, tremor and yawning, and a few from what the person reports. The total runs from 0 to 48.
It is used to judge how far into withdrawal a person is and to follow the course over hours. Many programs also use it to time the first dose of buprenorphine.
How to use itGiving it and scoring it
Rate each of the 11 items now, using the highest option that fits the person's signs or symptoms. The total is the sum of all 11 items, from 0 to 48. This page does the addition.
Record the time of the rating and, when you can, the time of the last opioid use and the opioid used. The scale does not capture them.
Interpreting the scoreScore ranges and what they suggest
| COWS total | What it suggests | Usual response |
|---|---|---|
| 0 to 4 | No or minimal withdrawalBelow the scale's lowest labeled range. | Recheck as the last dose wears off. A low score right after use is expected. |
| 5 to 12 | Mild withdrawalEarly or mild withdrawal. | Supportive and symptom care, and recheck. Some protocols begin buprenorphine near the top of this range. |
| 13 to 24 | Moderate withdrawalEstablished withdrawal. | Treat symptoms. Many protocols allow buprenorphine induction in this range. |
| 25 to 36 | Moderately severe withdrawalMarked withdrawal. | Treat actively, check hydration and look for other causes. |
| 37 to 48 | Severe withdrawalVery marked withdrawal. | Treat now, monitor closely and think about co-occurring withdrawal or another illness. |
The labeled ranges on the published scale are 5 to 12 mild, 13 to 24 moderate, 25 to 36 moderately severe, and more than 36 severe. A score of 0 to 4 is not labeled there, and is described here as no or minimal withdrawal.
Pearls and pitfallsTips and common mistakes
- Record the time of the last dose next to the score. A COWS means little without it.
- Before the first buprenorphine dose, waiting for a higher score lowers the chance of precipitated withdrawal. Low-dose induction lets you start without waiting.
- Do not count pulse, sweat or restlessness that comes from something else, such as exertion.
- Rate at regular intervals after treatment starts, to show the trend.
- Ask about alcohol and benzodiazepines in every opioid withdrawal. Their withdrawal can be dangerous and look like severe opioid withdrawal.
EvidenceAccuracy and reliability
- Wesson and Ling (2003) described the COWS as an 11-item clinician-administered scale to rate common signs and symptoms of opiate withdrawal and to follow them over time.
- Tompkins and colleagues (2009) compared it with the Clinical Institute Narcotic Assessment and supported its concurrent validity.
- The scale was not built to set a threshold for starting buprenorphine. The use of a score of about 8 to 12 for that purpose comes from clinical practice and protocols, and the American Society of Addiction Medicine guideline discusses induction timing.
Source, license and referencesWhere it comes from
The COWS was published by Wesson and Ling in 2003. The version hosted by the National Institute on Drug Abuse states that it may be copied and used clinically. Wording on this page follows that version.
- Wesson DR, Ling W. The Clinical Opiate Withdrawal Scale (COWS). J Psychoactive Drugs. 2003;35(2):253-259.
- Tompkins DA, Bigelow GE, Harrison JA, Johnson RE, Fudala PJ, Strain EC. Concurrent validation of the Clinical Opiate Withdrawal Scale (COWS) and single-item indices against the Clinical Institute Narcotic Assessment (CINA) opioid withdrawal instrument. Drug Alcohol Depend. 2009;105(1-2):154-159.
- American Society of Addiction Medicine. National Practice Guideline for the Treatment of Opioid Use Disorder: 2020 Focused Update. J Addict Med. 2020;14(2S Suppl 1):1-91.