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COWS Clinical Opiate Withdrawal Scale

The COWS rates 11 opioid withdrawal signs, total 0–48: 5–12 mild, 13–24 moderate, 25–36 moderately severe and >36 severe. It is commonly used to time buprenorphine induction, typically once the score is about 8–12 or higher.

Resting pulse rate (after sitting 1 minute) (/min)
Sweating (past ½ h, not due to room temperature or activity): No report of chills or flushing (0); Subjective report of chills or flushing (1); Flushed or observable moistness on face (2); Beads of sweat on brow or face (3); Sweat streaming off face (4)
Restlessness (observed during assessment): Able to sit still (0); Reports difficulty sitting still, but is able to do so (1); Frequent shifting or extraneous movements of legs/arms (3); Unable to sit still for more than a few seconds (5)
Pupil size: Pupils pinned or normal size for room light (0); Pupils possibly larger than normal for room light (1); Pupils moderately dilated (2); Pupils so dilated that only the rim of the iris is visible (5)
Bone or joint aches (new): Not present (0); Mild diffuse discomfort (1); Severe diffuse aching of joints/muscles (2); Rubbing joints or muscles and unable to sit still because of discomfort (4)
Runny nose or tearing (not from cold or allergy): Not present (0); Nasal stuffiness or unusually moist eyes (1); Nose running or tearing (2); Nose constantly running or tears streaming down cheeks (4)
GI upset (past ½ h): No GI symptoms (0); Stomach cramps (1); Nausea or loose stool (2); Vomiting or diarrhea (3); Multiple episodes of diarrhea or vomiting (5)
Tremor (outstretched hands): No tremor (0); Tremor can be felt, but not observed (1); Slight tremor observable (2); Gross tremor or muscle twitching (4)
Yawning (during assessment): No yawning (0); Yawning once or twice during assessment (1); Yawning three or more times during assessment (2); Yawning several times per minute (4)
Anxiety or irritability: None (0); Reports increasing irritability or anxiousness (1); Obviously irritable or anxious (2); So irritable or anxious that participation in the assessment is difficult (4)
Gooseflesh skin: Skin is smooth (0); Piloerection can be felt or hairs standing up on arms (3); Prominent piloerection (5)

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Interpretation

Result	Meaning
0–4	No active withdrawal
5–12	Mild
13–24	Moderate
25–36	Moderately severe
> 36	Severe

Formula

Pulse (≤80 = 0, 81–100 = 1, 101–120 = 2, >120 = 4) + sweating 0–4 + restlessness 0–5 + pupils 0–5 + bone/joint aches 0–4 + runny nose/tearing 0–4 + GI upset 0–5 + tremor 0–4 + yawning 0–4 + anxiety/irritability 0–4 + gooseflesh 0–5. Range 0–48.

Clinical pearls

Starting buprenorphine too early can precipitate withdrawal; many protocols wait for COWS ≥8–12, longer after methadone or fentanyl.
Score only what you observe or the patient reports for the current episode; anxiety, tachycardia or GI symptoms from other causes inflate the score.

Examples

cows hr 104 sweating 2 restlessness 1 pupils 2 aches 1 runny nose 2 gi 2 tremor 1 yawning 2 anxiety 2 gooseflesh 0 COWS score: pulse 88, beads of sweat, frequent shifting, moderately dilated pupils, vomiting, gooseflesh felt opioid withdrawal score pulse 75 all other items 0

FAQ

What COWS score is needed to start buprenorphine?

Protocols vary, but buprenorphine is usually started at a COWS of about 8 to 12 or higher, so that the patient is in objective withdrawal.

What is a severe COWS score?

More than 36 is severe withdrawal; 25–36 is moderately severe.

Evidence

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

Psychiatry & Substance Use · Reviewed 2026-10-14 · Methodology