Clinical Opiate Withdrawal Scale (COWS): A Comprehensive Guide to Assessment and Management

The Clinical Opiate Withdrawal Scale (COWS) is a well established assessment tool to measure the severity of opiate withdrawal symptoms. It’s used in clinical settings to monitor withdrawal, guide treatment and evaluate interventions. This article will go into detail about the COWS, including its development, components, administration, interpretation and clinical use.
Understanding Opiate Withdrawal: Physiology and Symptomatology
Opiate withdrawal is a physiological and psychological response that occurs when an individual reduces or stops prolonged opiate use. Opiates including natural opiates such as heroin and morphine, as well as synthetic painkillers, bind to opioid receptors in the brain, spinal cord and gut, producing analgesia and euphoria. Chronic opiate use leads to neuroadaptation where the body becomes dependent on the presence of the drug to maintain homeostasis.
When opiate use is stopped the nervous system becomes hyperactive because of the absence of the inhibitory effects of the opiates. This leads to a range of symptoms including anxiety, restlessness, muscle aches, sweating, runny nose, dilated pupils, goosebumps, nausea, vomiting, diarrhoea and abdominal cramps. The severity and duration of withdrawal symptoms vary depending on the type of opiate used, duration of use, dose and individual differences.
The Clinical Opiate Withdrawal Scale (COWS): Development and Purpose
The Clinical Opiate Withdrawal Scale (COWS) was developed to provide a standardised and objective way of measuring opiate withdrawal. Before the development of COWS clinicians relied primarily on subjective observation and patient self-reporting which was unreliable and inconsistent. The COWS aims to improve the accuracy,consistency and standardisation of withdrawal assessment and therefore enable better clinical decision making.
The tool was designed to be easily administered by healthcare professionals in various settings including inpatient units. By quantifying the severity of withdrawal the COWS helps clinicians decide on the level of intervention, monitor the patient and adjust treatment as needed.
Clinical Opiate Withdrawal Scale (COWS): What’s in it? A Breakdown of the Assessment Criteria

The COWS has 11 items, each assessing a different sign or symptom of opiate withdrawal. These are:
- Resting Pulse Rate: Measures the patient’s heart rate after a period of rest. An elevated pulse rate indicates withdrawal.
- Sweating: Assesses the presence and severity of sweating (excluding sweating due to room temperature or activity).
- Restlessness: Evaluates the patient’s ability to sit still, scores range from normal to fidgety to overtly restless.
- Pupil Size: Assesses mydriasis (pupil dilation) characteristic of opioid withdrawal or miosis (pupil constriction) which occurs during opioid intoxication. Bone or Joint Aches: Assesses the presence and severity of aches in bones or joints.
- Runny Nose or Tearing: Evaluates the presence and severity of nasal discharge or excessive tearing.
- Gastrointestinal Upset: Assesses symptoms such as nausea, vomiting and diarrhoea.
- Tremor: Evaluates the presence and severity of tremors in the hands or other body parts.
- Piloerection: Assesses the presence of raised hair follicles or ‘goosebumps’ on the skin.
- Anxiety or Irritability: Measures the patient’s level of anxiety, irritability and agitation.
- Yawning: Assesses the frequency of yawning which is a common symptom of opiate withdrawal.
Each item is scored on a 0-4 or 0-5 scale, with higher scores indicating greater withdrawal severity. The total COWS score is the sum of all 11 items.
Administering the Clinical Opiate Withdrawal Scale: Guidelines for Accurate and Reliable Scoring

For accurate scoring, Clinical Opiate Withdrawal Scale (COWS) should be administered by trained healthcare professionals, including nurses and medical staff familiar with the signs and symptoms of opiate withdrawal. The assessment should be done in a quiet private space to minimise distractions and patient discomfort.
The administrator should explain the purpose of the assessment to the patient and answer any questions they may have. Observe the patient and ask specific questions about their symptoms. Use objective criteria to score each item, rely on observable signs and patient reports.
Interpreting COWS Scores: Severity Levels and Clinical Implications
The total COWS score gives a numerical value for withdrawal severity. The following are the common categories used to interpret COWS scores:
- 0-5: None to Minimal Withdrawal
- 5-12: Mild Withdrawal
- 13-24: Moderate Withdrawal
- 25-36: Moderately Severe Withdrawal
- More than 36: Severe Withdrawal
These scores help guide clinical decisions regarding withdrawal management, alongside patient history, medical risk factors, and symptom severity. Regular COWS assessments allow clinicians to monitor treatment and adjust as needed.
The COWS in Context: Utility in Inpatient Treatment Settings
In inpatient settings the Clinical Opiate Withdrawal Scale (COWS) is particularly useful for monitoring patients going through opiate withdrawal. Regular assessments (typically 3-4 times a day in acute withdrawal) helps the clinician track the progression of withdrawal symptoms and identify potential problems. This allows for timely interventions to reduce discomfort and prevent bad outcomes.
The COWS can also be used to compare different treatment approaches. For example the clinician can compare COWS scores before and after medication to see what impact it has on withdrawal symptoms. This information can inform decisions about medication dose and duration of treatment.
Pros and Cons of the Clinical Opiate Withdrawal Scale
The Clinical Opiate Withdrawal Scale (COWS) has several advantages, providing aa standardised, objective and structured assessment of opiate withdrawal severity, though some elements still rely on patient self-reporting which may be influenced by mood, motivation and cognitive impairment. While COWs primarily measures physical withdrawal symptoms, it does not capture the full range of psychological and behavioural symptoms of opiate withdrawal like dysphoria, anxiety and cravings, but has nevertheless been validated in many studies and is widely used in clinical practice.
Beyond the COWS: Holistic Approaches to Managing Opiate Withdrawal
While the Clinical Opiate Withdrawal Scale (COWS) is useful for assessing and monitoring opiate withdrawal, it is merely one component of a comprehensive evaluation. A holistic approach to managing opiate withdrawal requires addressing the physical, psychological, and social needs of the individual.
Behavioural medicine and the biopsychosocial approach is essential for long-term recovery, integrating behavioural medicine, psychological support and lifestyle changes to promote long term recovery and wellbeing.
At Highlands Recovery, COWS is an integral part of our withdrawal management program, providing each individual with a tailored treatment plan adapted to their needs. Our four phase recovery program covers stabilisation, trauma reprocessing, integration and consolidation to support a clients journey.
Highlands Recovery located near Sydney in Australia uses a behavioural medicine model incorporating biological, psychological and social health. Highlands Recovery believes in recovery that lasts a lifetime. The program utilises a multidisciplinary team, ensuring clients receive care from various specialists.
Reviewed by: Dr. Emma Bardsley

Dr Emma Bardsley is a neuroscientist with a PhD from Oxford and a post doctorate from Auckland University, along with an undergraduate degree in Pharmacology from King’s College London. She has lectured extensively on neuroscience, physiology, and pharmacological interventions, bridging foundational research and its clinical applications. With a strong record of publications in high-impact journals and extensive experience in scientific writing, editing, and peer review, she excels at translating complex research into practical insights. Based in New Zealand and collaborating internationally, Emma is dedicated to advancing understanding and treatment in the fields of trauma, addiction, and recovery.
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