The COWS scale: how helpful is it?

COWS stands for Clinical Opioid Withdrawal Scale, and it’s probably the most commonly used tool to determine the degree of opioid withdrawal experienced by the patient. The scale has eleven items related to opioid withdrawal. Some are subjective, like the question about the degree of anxiety or irritability the patient is feeling. Some items are strictly objective, such as pupil size and pulse rate. And some are sort of a combination of objective and subjective, like the question asking about both nausea and vomiting. The patient may report nausea and score points on the scale, and if the patient vomits, this scores more points.

I’ve worked in clinics that used the COWS for each dose increase, and I’ve worked in clinics that didn’t use the COWS at all.

I think it’s a good tool, but has some drawbacks. I use it during dose induction, particularly on a patient new to medication-assisted treatment. Sometimes patients aren’t sure how they’re “supposed” to feel on replacement medication, and a COWS score gives me a better idea of how much withdrawal they are in.

For example, I had a patient who felt much fatigue in the evenings. He’s been on the program about a month, and had been dosing at 70mg for about a week. He worked at a strenuous job, and got off work around 5pm. One day, he told the nurses that he needed an increase, since it felt like his methadone “gave out” as soon as he got home, and he had to take a nap before his evening meal because he was so sleepy. When the nurses heard him say   “sleepy,” they correctly became worried he was on too much methadone, and sent him to see me. When I checked him just before dosing the next morning, his pupils were a wide 8 mm and reacted briskly to the bright light I shone in his eyes. He was in withdrawal and he felt better after a few dose increases. His use of the word sleepy was confusing, since to us, we worry “sleepy” means “headed towards a methadone overdose.”

Sometimes, a patient reports severe withdrawal but doesn’t score very high on the COWS. I don’t assume the patient is lying, because some patients don’t tolerate withdrawal symptoms easily. More commonly, I see patients, mostly long-term users, who are in what I would consider to be moderate or severe withdrawal by their COWS score, but they experience it as “not so bad, I’ve felt worse”

In another example, I had a patient on 110mg who reported terrible withdrawal, to the point she couldn’t function during the day. She was restless, anxious, jittery, and felt like her heart was racing. She wasn’t sleeping well. This was puzzling, since a month ago she’d been fine on that same dose. There were no new medications, no change in activities, and she wasn’t drinking alcohol (a common reason for drop in methadone blood level). On the COWS, she scored an 8, but when I looked at the actual COWS, she scored very high on the more subjective items, yet her pupils were pinpoint and her pulse rate in the 60’s

The more we talked, the more I suspected anxiety as the cause of her symptoms. She had a terribly stressful living situation. She was saving money to move out on her own, but felt like she had to endure the circumstances in the short term. In this case, she appeared to be blaming opioid withdrawal for her symptoms of anxiety, and anxiety was a normal response for what she was experiencing. She didn’t need a higher dose of methadone; she needed someone to help her think of better immediate options for safe housing.

I do not think a COWS score is helpful for fine-tuning a patient’s dose of methadone. Many times the COWS score doesn’t pick up subtle withdrawal, so I don’t tend to use it for higher dose changes.

COWS scores are helpful when defending one’s self from regulatory bodies. About five years ago, a state investigator took me to task for authorizing dose increases. “You just believe them when they say they’re in withdrawal?” she asked sarcastically. The investigator didn’t think I should increase the doses of those patients, and yet the studies clearly show methadone patients have better outcomes if they are on an adequate dose. By doing a COWS score, the patient’s signs and symptoms are recorded in the chart for an investigator to see.

In summary, the COWS scale is a useful tool, though probably more useful at lower doses. Like all tools, it’s helpful in some situations, but it’s not perfect. It should be used alongside our other tools, like talking and listening to our patients both before and after dosing, using blood levels in rare cases, and always asking about other medications or new medical problems.