All opioids can cause sweating and flushing, but methadone is perhaps worse to cause sweating than other opioids. Buprenorphine also can cause sweating, but it is usually less of a problem than for patients on methadone.
We don’t know exactly why opioids make people sweat, but it is related to opioids’ effects on the thermoregulatory centers of the brain.
Excess sweating can also be caused by opioid withdrawal. If other withdrawal symptoms are present, like runny nose, muscle aches, or nausea, an increase of the methadone dose may help reduce the sweating.
At least half of all patients on methadone report unpleasant sweating, but some patients have sweats that are more than just inconvenient. These patients report dramatic, soaking sweats, bad enough to interfere with life.
What can we do about this sweating?
First, non-medication methods can be attempted. These methods include common sense things like wearing loose clothing, keeping the house cool, and losing weight. Regular exercise helps some people. Talcum powder, sprinkled on the areas that sweat, can help absorb some of the moisture. Antiperspirants can be used in the underarm area, but also in any area that routinely becomes sweaty. The antiperspirant can be applied at bedtime so sweating won’t interrupt sleep. There are prescription antiperspirants, like Drysol or Xerac, but these sometimes can be irritating to the skin. Avoid spicy foods, which can also cause sweating.
Make sure the sweating isn’t coming from any other source, like an overactive thyroid, and check your body temperature a few times, to make sure you don’t have a fever, indicating the sweating could be from a smoldering infection. A trip to the primary care doctor should include some basic blood tests to rule out medical causes of sweating, other than the dose of methadone.
Some prescription medications can help, to varying degree, with sweating.
Clonidine, a blood pressure medication that blocks activation of part of the central nervous system, blocks sweats in some patients.
Anti-cholenergic medicines, drugs block the effect of the neurotransmitter acetylcholine in the involuntary nervous system, block sweating. Anticholinergics tend to dry all secretions, causing such common side effects as dry mouth and dry eyes. These medications can cause serious side effects, so they must be prescribed by a doctor familiar with the patient’s medical history.
Some examples of anticholinergics include oxybutynin (also used for urinary leakage), bipereden (used in some Parkinson patients), scopolamine (also used for sea sickness), and dicyclomine (used for irritable bowel syndrome). All of these have been used for excessive sweating with various degrees of success, in some patients.
For unusually bad situations, Botox can be injected under the skin of the most affected areas, like armpits, palms and soles. Obviously, this is somewhat of a last-resort measure.
Patients affected with severe sweats, unresponsive to any of the above measures, need to decide if the benefit they get from methadone outweighs the annoyance of the side effects. In other words, if being on methadone has kept them from active drug addiction, which is a potentially fatal illness, it would probably be worth putting up with sweating, even if it’s severe.