This Clinical Opiate Withdrawal Scale (COWS) calculator evaluates the severity of withdrawal symptoms in patients after opioid use. Below the form you can find more information on the criteria involved in the scale and how the score is interpreted.

Resting Pulse Rate (bpm)


Restlessness observation during assessment

Pupil size

Bone or joint aches

Runny nose or tearing

GI Upset

Tremor observation of outstretched hands

Yawning observation during assessment

Anxiety or irritability

Gooseflesh skin

How does this Clinical Opiate Withdrawal Scale (COWS) calculator work?

The COWS model, the Clinical Opiate Withdrawal Scale is an 11 item simple and straight forward questionnaire that needs to be administered by a medical professional in order to determine whether the patient, either in or out patient, suffers from any significant withdrawal symptoms and if so, evaluate the severity of them.

The criteria used and some of the indications given to clinicians for the assessment of opioid dependence is explained in the following lines:

■ Resting Pulse Rate (bpm) – the pulse rate should be measured once the patient has been lying down for at least 1 minute.

■ Sweating – any sign of this kind not accounted for by room temperature or patient activity in the last 30 minutes.

■ Restlessness observation during assessment – measuring inability to sit still.

■ Pupil size – from normal to different degrees of dilation.

■ Bone or joint aches – only the pain components that can be attributed to opiate withdrawal not to other comorbidities.

■ Runny nose or tearing – not accounted for by cold symptoms or allergies.

■ GI Upset – during the last 30 minutes.

■ Tremor observation of outstretched hands.

■ Yawning observation during assessment – number of yawns during the observation period.

■ Anxiety or irritability – either one or both experienced.

■ Gooseflesh skin – with or without piloerection.

The questionnaire in the Clinical Opiate Withdrawal Scale calculator can be used to assess patients in primary care but also as a monitoring tool in time. COWS is officially available in Appendix 2 of the National Guidelines for Medication-Assisted Treatment of Opioid Dependence.

One of the strong points is that it combines clinical data, objective data with subjective data thus not allowing for any misinterpretations. However, clinical judgment should still mark the final decision. The study originated as a mean to monitor patient evolution in the withdrawal treatment with buprenorphine induction. But nowadays it is used in a variety of clinical settings from opioid detox to chronic pain management.

Buprenorphine treatment is based on the opiate agonist properties of this substance on physically dependent patients. Usually induction is recommended for cases that are already in a COWS score of over 6. For cases below this score, that are experiencing just few to none withdrawal symptoms, the medication might cause them and produce unnecessary discomfort to the patient.

Another tool used in assessing dependence risk but before prescription is the ORT, developed to evaluate the risk of a patient becoming dependent of opioid medication during pain treatment.

Symptoms of opioid withdrawal are similar in general with varying degrees of severity and duration as well as different periods of installation. Most common signs include:

■ lacrimation;

■ rhinorrhoea;

■ sneezing;

■ yawning;

■ hot and cold flushes;

■ sweating;

■ tremor;

■ anxiety;

■ restlessness;

■ irritability;

■ sleep pattern disturbed.

COWS interpretation

The result provides the stage of severity for opiate withdrawal and provides a trusting measure of the physical dependence on opioids developed by the patient. The score result is compared with the cut offs for withdrawal severity as described below:

■ <5 – no relevant withdrawal symptoms;

■ 5 - 12 - mild withdrawal;

■ 13 - 24 - moderate withdrawal;

■ 25 - 36 - moderately severe withdrawal;

■ >36 - severe withdrawal.


1) Wesson DR, Ling W. (2003) The Clinical Opiate Withdrawal Scale (COWS). J Psychoactive Drugs; 35(2):253-9.

2) Tompkins DA, Bigelow GE, Harrison JA, Johnson RE, Fudala PJ, Strain EC. (2009) 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; 105(1-2):154-9.

01 Oct, 2015