Qbrexza for Underarm Sweating: Benefits and Risks

Qbrexza is a prescription cloth for primary axillary hyperhidrosis#

Qbrexza is the U.S. brand name for a single-use cloth containing 2.4% glycopyrronium, a topical anticholinergic. The FDA label indicates it for primary axillary hyperhidrosis in adults and children age 9 and older. It is applied to the underarms only, once every 24 hours, using one cloth for both sides.[2]

Those boundaries matter. Qbrexza is not labeled as a wipe for sweaty hands, feet, face, or generalized sweating. It is also not an ordinary cosmetic antiperspirant. It is prescription-only and can produce systemic anticholinergic effects even though it is applied to the skin.

Two phase 3 trials found greater improvement than vehicle at 4 weeks#

ATMOS-1 and ATMOS-2 were randomized, double-blind, vehicle-controlled phase 3 trials involving 697 people with primary axillary hyperhidrosis. Participants used glycopyrronium cloth or vehicle once daily for 4 weeks. In the pooled analysis, 59.5% of the glycopyrronium group and 27.6% of the vehicle group achieved at least a 4-point improvement on the Axillary Sweating Daily Diary severity item at week 4.[1]

The result is clinically meaningful because it measures how severe the sweating felt to patients, not only the weight of sweat collected in a controlled room. A separate HDSS endpoint also favored glycopyrronium in both trials.[1]

The evidence is not uniformly perfect. The controlled period was only 4 weeks. One coprimary gravimetric sweat-production endpoint in ATMOS-1 was not statistically significant in the original analysis and became significant in a prespecified sensitivity analysis that excluded an analysis center with extreme outlier data.[4] These studies were sponsored and funded by Dermira, which also funded development of the patient-reported-outcomes manuscript; several authors were employees or consultants.[1] The strongest conclusion is therefore narrow: Qbrexza improved patient-reported axillary sweating more often than vehicle over 4 weeks.

Anticholinergic side effects are part of the tradeoff#

In the pooled ATMOS trials, dry mouth occurred in 24.2% of glycopyrronium participants and 5.6% of vehicle participants. Mydriasis, or pupil dilation, occurred in 6.8% and 0%, respectively. Urinary hesitation and blurred vision were also reported more often with glycopyrronium.[1]

The current label warns about new or worsening urinary retention, reduced ability to cool the body in hot conditions, transient blurred vision, and accidental eye exposure. It instructs users to wash their hands after discarding the cloth because transfer to the eyes can cause pupil dilation and blurred vision.[2]

The label lists contraindications for medical conditions that can be worsened by anticholinergic effects, including glaucoma, paralytic ileus, severe ulcerative-colitis complications, myasthenia gravis, and Sjögren syndrome.[2] A prescriber must determine whether those warnings apply; a blog article cannot do that safely.

Qbrexza is not proven superior to aluminum chloride#

No direct randomized trial in this evidence set compares Qbrexza with Drysol or another aluminum chloride product. The Qbrexza trials compare active cloth with its vehicle. Aluminum chloride studies use different concentrations, body sites, outcomes, and durations. Comparing percentages across those separate studies would create a head-to-head claim the evidence did not test.

The practical evidence distinction is clearer than a ranking. Qbrexza has large vehicle-controlled trials for primary axillary hyperhidrosis and a prescription anticholinergic safety profile. Aluminum chloride is supported by smaller studies across different concentrations and body sites, and those studies report local irritation in some participants. See the Drysol evidence review for the body-site limits of those studies.

Long-term data are less certain than the 4-week comparison#

An open-label extension followed participants for up to 44 additional weeks.[3] Open-label follow-up can help identify recurring adverse events and whether benefits appear to persist, but it does not preserve the randomized vehicle comparison. Attrition also matters in a long extension. It should not be summarized as proof that every user maintains the same benefit for a year.

Bottom line#

Qbrexza has credible randomized evidence for primary underarm hyperhidrosis: in 697 trial participants, patient-reported sweating improved substantially more often with glycopyrronium cloth than with vehicle at 4 weeks.[1] The same evidence shows a real anticholinergic burden, and the FDA label restricts how and where the cloth is used.[2] It is a prescription option to discuss with a qualified clinician, not a universally safer or more effective replacement for every antiperspirant.

This article is educational and does not provide an individualized prescription or determine whether Qbrexza is safe for a particular person.

References#

1. Pariser DM, Hebert AA, Drew J, et al. Topical glycopyrronium tosylate for the treatment of primary axillary hyperhidrosis: patient-reported outcomes from the ATMOS-1 and ATMOS-2 phase III randomized controlled trials. Am J Clin Dermatol. 2019;20(1):135-145. PMC full text

2. U.S. National Library of Medicine. Qbrexza (glycopyrronium cloth) prescribing information. Revised November 2022. DailyMed label

3. Glaser DA, Hebert AA, Nast A, et al. A 44-week open-label study evaluating safety and efficacy of topical glycopyrronium tosylate in patients with primary axillary hyperhidrosis. Am J Clin Dermatol. 2019. PubMed PMID 31111409

4. U.S. Food and Drug Administration. Multidisciplinary review and evaluation, NDA 210361: Qbrexza (glycopyrronium) cloth, 2.4%. FDA review PDF