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    COWS Score for Opiate Withdrawal

    Quantifies severity of opiate withdrawal.
    When to Use
    Why Use
    • COWS may be used in both inpatient and outpatient settings:
      • During Detox: for the general monitoring of opiate withdrawal during opioid detoxification.
      • During Pain Treatment: for patients receiving opiates for the treatment of acute or chronic pain who may show subtle signs of opiate withdrawal.
      • In the ED & More: for patients requesting methadone for opiate withdrawal symptoms and their enrollment in methadone maintenance treatment has not been verified.
    • COWS is most commonly used in buprenorphine induction, and is recommended specifically for this use.
    • The Clinical Opiate Withdrawal Score (COWS) limits possibility of feigned responses by combining subjective symptoms with objective signs. (Wesson DR 2003)
    • COWS was first published in a training manual for buprenorphine treatment.
    • While commonly used for buprenorphine or buprenorphine/naloxone induction, it can also be useful in a variety of office, clinic and hospital settings. Examples include the assessment of acute opiate withdrawal during an opiate detoxification program, methadone maintenance treatment, and the treatment of chronic pain.
    • The scale is designed to be used quickly (< 2 minutes) by clinicians.
    • Be aware that the prescribing of buprenorphine and buprenorphine/naloxone in the context of opioid addiction treatment requires additional credentialing by the DEA.
    • As stated above, it combines subjective and objective components, limiting the possibility of feigned responses.
    • It can be serially administered to track changes in the severity of withdrawal symptoms over time or in response to treatment.


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    Using COWS in buprenorphine induction treatment:

    • Buprenorphine is a partial opiate agonist that can precipitate florid opiate withdrawal if administered to a physically-dependent patient.
    • In buprenorphine induction, it is important that a patient is already in mild to moderate opiate withdrawal prior to administration. This would be equivalent to a COWS score >5-6 (>10 preferable).
    • This is important as otherwise patients experience precipitated withdrawal, a rapid and intense onset of withdrawal symptoms initiated by the medication.
    • It is not reliable to use “time since last opioid use” since patients are not always truthful in reporting their last use, and metabolism varies from patient to patient.


    • COWS can help set patient expectations prior to buprenorphine treatment, as they will likely experience a certain amount of discomfort.
    • Opioid detoxification works best with adjunctive treatments such as psychotherapy and support groups.

    Critical Actions

    Always consider the possibility of comorbid withdrawal conditions from alcohol, benzodiazepine, or sedative-hypnotics, which may be life threatening alone or in combination.


    Addition of the selected points; as above.

    Facts & Figures

    Score interpretation:

    • <5 - no active withdrawal
    • 5-12 - mild withdrawal
    • 13-24 - moderate withdrawal
    • 25-36 - moderately severe withdrawal
    • >36 - severe withdrawal

    Evidence Appraisal

    Original article

    This article presents the COWS scale and discusses the rationale for its development. As described in detail above, the scale consists of an 11-item rating system that can be completed within two minutes by a trained observer and can track opioid withdrawal as differentiated from opioid toxicity through serial measurements. It was designed to be administered quickly and was intended to improve upon existing measurement tools.

    Validation study

    This study validated the COWS in comparison to the validated Clinical Institute Narcotic Assessment (CINA) scale. It used a double-blind randomized design to compare opioid withdrawal symptoms for intramuscularly administered placebo vs. naloxone to 46 opioid-dependent participants. COWS and CINA scores during the naloxone challenge session were well correlated with Pearson correlation coefficient of 0.85 (p<0.001) while placebo was not associated with any significant elevation in either score. Additional evidence of concurrent validity was provided by comparing COWS with the self-reporting visual analog scale (VAS); COWS scores correlated well with peak VAS scores of bad drug effect (r=0.57, p<0.001) and feeling sick (r=0.57, p<0.001). Cronbach’s alpha for the COWS was 0.78, indicating good internal consistency (reliability).

    Dr. Donald R. Wesson

    About the Creator

    Donald R. Wesson, MD, is a board-certified psychiatrist and currently on the executive council of the California Society of Addiction Medicine. He formerly served as chief psychiatrist at the Haight-Ashbury Free Medical Clinic in San Francisco while maintaining a private practice. Dr. Wesson has been the principal investigator for 20+ clinical trials, some sponsored by the National Institute on Drug Abuse (NIDA), and has authored numerous publications.

    To view Dr. Donald R. Wesson's publications, visit PubMed

    About the Creator
    Dr. Donald R. Wesson