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What is the COWS score?
The COWS score — short for Clinical Opiate Withdrawal Scale — is a way of putting a number on how much withdrawal someone is experiencing at a given moment. A physician looks at a set of physical signs and symptoms, scores each one, and adds them up. The total gives a rough picture of where the person is in the withdrawal process.
COWS was first described in a buprenorphine prescribing training manual in 1999, and was formally published by Wesson and Ling in 2003. It became widely used because it is quick — it takes about two minutes — and it gives a number that can be tracked over time.
It is one of the most commonly used tools for gauging opioid withdrawal. It is not the only one, and it has real limitations — more on that below.
What it looks at
The 11 items on the COWS scale.
The COWS assessment looks at 11 things. Each one is scored based on what the physician sees or what the patient describes. The scores are added together for a total between 0 and 47.
Resting heart rate
0 = 80 or below · 1 = 81–100 · 2 = 101–120 · 4 = over 120
Sweating
0 = no sweat · 1 = barely noticeable · 2 = beads on forehead · 4 = streaming
Restlessness
0 = able to sit still · 1 = difficulty but able · 3 = frequent shifting · 5 = unable to sit still
Pupil size
0 = normal or small · 1 = possibly larger · 2 = moderately dilated · 5 = only a rim of color visible
Bone or joint aches
0 = none · 1 = mild discomfort · 2 = rubbing joints, reports aching · 4 = unable to keep still
Runny nose or watery eyes
0 = none · 1 = stuffiness or slightly watery · 2 = running freely or tears · 4 = constantly wiping
Stomach upset
0 = none · 1 = cramps · 2 = nausea or loose stool · 3 = vomiting or diarrhea · 5 = multiple episodes
Tremor
0 = none · 1 = can feel but not see · 2 = slight visible tremor · 4 = severe tremor or twitching
Yawning
0 = none · 1 = once or twice · 2 = three or more times · 4 = several times per minute
Anxiety or irritability
0 = none · 1 = reports increasing · 2 = obviously anxious · 4 = so intense the assessment is difficult
Goosebumps
0 = smooth skin · 3 = visible goosebumps · 5 = prominent goosebumps with raised hairs
What the total means
COWS score ranges.
The total score is grouped into ranges:
5–12: Mild withdrawal.
13–24: Moderate withdrawal.
25–36: Moderately severe withdrawal.
More than 36: Severe withdrawal.
These ranges were set by the authors based on their clinical experience — not through a formal testing process. They are useful as a general guide, but they are not precise cutoffs. A person can feel terrible and score in the mild range, or score higher than expected without feeling as bad as the number suggests.
How it is used
Some physicians use it. Others do not.
Some physicians use the COWS score to help decide when to start Suboxone (buprenorphine). Because starting too soon can cause precipitated withdrawal — a sudden worsening of symptoms — having a way to gauge where someone is in the withdrawal process can be helpful.
Other physicians rely more on what the patient tells them and what they observe in conversation — the quality of symptoms, not just their score. Both approaches are used in practice. There is no single correct way to assess withdrawal, and the COWS score is one tool among several.
How your physician approaches this depends on their judgment, the specific opioid involved, and your situation.
Other tools
Other ways withdrawal is assessed.
COWS is the most widely used, but it is not the only option:
SOWS (Subjective Opiate Withdrawal Scale). The patient rates their own symptoms — how they feel, in their own assessment — rather than the physician scoring what they observe. This can be especially useful in telehealth, where some physical signs are harder to see through a screen. SOWS captures how the patient actually feels, which does not always match what can be seen from the outside.
CINA (Clinical Institute Narcotic Assessment). Similar in structure to COWS but organized differently. Used in some treatment settings.
OOWS (Objective Opiate Withdrawal Scale). Focuses on what can be directly observed rather than what the patient reports. Less commonly used.
Clinical conversation. Many experienced physicians assess withdrawal through a detailed conversation about what the patient is experiencing — when it started, what it feels like, how severe it is — without assigning a formal score. This is not less valid. It is a different approach, and for many patients it captures things that a checklist does not.
In practice, many physicians use a combination — a formal tool alongside what the patient tells them and what they observe.
What it cannot tell you
Limitations.
The COWS score is useful, but it has real limits worth understanding:
- The severity categories were not formally tested. The ranges (mild, moderate, severe) were based on the authors' experience when the scale was first published. A more structured review came later, in 2009 — and even that involved relatively mild withdrawal under controlled conditions.
- The number does not always match how someone feels. Withdrawal is a whole-body experience. Reducing it to a number has limits. Some patients feel much worse than their score suggests. Others score higher than expected without feeling as bad.
- With fentanyl, the score can be misleading. Fentanyl stays in body tissue longer than most other opioids. A patient may appear to be in enough withdrawal — and score in a range that would normally suggest it is time to start Suboxone — while fentanyl is still being slowly released. This mismatch is one of the reasons fentanyl makes starting treatment more complex.
- It measures a moment, not a trajectory. Withdrawal changes over hours. A single score is a snapshot, not a full picture.
- Some items are hard to assess on your own. Pupil size and resting heart rate require tools or a second person. Self-assessment has limits.
None of this means the COWS score is not useful — it is. It just means it is one piece of information, not the whole picture.
If you are looking into treatment
You do not need to assess yourself before calling.
If you came across the COWS score because you are thinking about starting treatment, or because someone mentioned it to you, the most important thing to know is this: you do not need to score yourself before reaching out. Your physician will handle the assessment — whether they use the COWS scale, another tool, or a clinical conversation — and will walk you through what to expect and when to start.
The COWS score is a tool that helps some physicians organize what they see. It is not a test you need to pass.
At MyStreetHealth, same-day visits are usually available. Your physician will evaluate where you are and guide you through the process.
Sources
Where this information comes from.
Wesson DR, Ling W — The Clinical Opiate Withdrawal Scale (J Psychoactive Drugs, 2003)
The original publication of the COWS scale, describing the 11-item assessment and scoring methodology.
Tompkins DA et al. — Concurrent Validation of the COWS (Am J Drug Alcohol Abuse, 2009)
First formal testing of the COWS against other withdrawal instruments, using naloxone challenge in opioid-dependent volunteers.
Gregory ME et al. — Incidence of Buprenorphine-Precipitated Opioid Withdrawal (Addiction, 2025)
Systematic review examining precipitated withdrawal during buprenorphine initiation, including the challenges posed by fentanyl.
Scoping review of withdrawal assessment tools — their development history, limitations, and emerging alternatives.
Related
← All Learn topics · Starting Suboxone · Precipitated withdrawal · Fentanyl treatment · How to get Suboxone treatment online
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Common questions
Frequently asked
What is the COWS score?
The Clinical Opiate Withdrawal Scale — a tool that measures opioid withdrawal by scoring 11 physical signs and symptoms. Total scores range from 0 to 47. It was first published in 2003 and is one of the most commonly used withdrawal assessment tools.
What COWS score do you need to start Suboxone?
There is no universal answer. Some physicians use the score as a guide; others rely on conversation and observation. The approach depends on the opioid involved, the physician's judgment, and your situation.
Is the COWS score accurate with fentanyl?
It can be unreliable. Fentanyl stays in the body longer than most other opioids, and patients can appear to be in sufficient withdrawal based on their score while fentanyl is still present. This is one of the reasons some physicians use alternative approaches to starting Suboxone for patients with fentanyl use.
Can I do the COWS assessment on my own?
You can review the symptoms, but some items are difficult to assess accurately on your own. The score is designed to be part of a clinical evaluation. If you are in withdrawal and considering treatment, the best step is to speak with a MyStreetHealth physician.