4 Findings About Methantheline for Excessive Sweating

The larger trial favored methantheline for underarm sweating

A trial published in 2013 randomized 339 people to oral methantheline bromide, 50 mg three times daily, or placebo for 28 days.¹

Mean underarm sweat collected over five minutes fell from 168 to 99 mg with methantheline and 161 to 130 mg with placebo. The between-group result favored the medicine. These are measured amounts of sweat, not percentages of people whose sweating stopped.¹

Symptom-severity and quality-of-life scores also favored treatment. Riemser funded the trial, and two authors were company employees. The published abstract does not provide a long-term comparison.¹

Underarm improvement did not establish a benefit for palms

The 2004 trial² abstract describes 41 participants, including 31 women. They received 50 mg twice daily or placebo for four weeks. Underarm sweat decreased in the treated group; the researchers found no difference between groups in palm sweat production.²

The trial’s positive underarm conclusion should not become a claim that the tablet treats every sweaty body area. Its abstract specifically found no evidence of a clinically relevant reduction in palm sweating.²

Four-week results came with frequent dry mouth

A 2017 NIHR review assessed the two placebo-controlled trials as having high or unclear risk of bias. It judged the evidence low quality and the added symptom and quality-of-life benefits potentially too small to matter clinically.³

In the earlier trial, the review reports dry mouth in 34.8% with methantheline versus 5.6% with placebo at week four. In the larger trial it reports numbers of dry-mouth events, which should not be presented as percentages of patients.³

Both trials lasted four weeks. Those findings cannot establish the balance of benefit and harm over years.³

The German indication and precautions are specific

The June 2026 German prescribing information covers persistent primary underarm hyperhidrosis lasting at least a year and insufficiently controlled with topical treatment. It says no data are available for use beyond four weeks and distinguishes sweating caused by another illness.⁴

Prescribing requires checks for conditions including narrow-angle glaucoma, obstructive urine retention and heart-rhythm disorders. The information restricts use during pregnancy or breastfeeding to situations with a strong medical justification. The information also advises avoiding driving or dangerous machinery until six hours after the last dose, because blurred vision can occur.⁴

Ask the prescriber which body area is being treated, when benefit will be reviewed, and what to do about dry mouth or visual symptoms. Ask a pharmacist about current local availability and the applicable product information.

The “Step-Up Conversation” in Arms Up suggests bringing your worst sweating zone, severity score and prior treatments, then asking about comparisons, duration and side effects. Our oral sweat-medicine heat guide addresses hot-weather planning separately.