Key points

Advice

The content of this evidence summary was up-to-date in March 2017. See the summary of product characteristics (SPCs), British national formulary (BNF) or the MHRA or NICE websites for up-to-date information.

Regulatory status: off-label use of a licensed medicine. Oxybutynin is an antimuscarinic medicine that can be used to treat hyperhidrosis (excessive sweating); use for this indication is off-label.

Overview

This evidence summary includes 4 studies (3 randomised controlled trials [RCTs] and 1 quasi-randomised controlled trial) that investigated oxybutynin 2.5 mg to10 mg for treating hyperhidrosis in adults. All the studies compared oxybutynin with placebo and were in non-UK settings.

Three studies found that more people treated with oxybutynin reported an improvement in symptoms of hyperhidrosis compared with those treated with placebo; the difference between the groups was statistically significant in all studies. Volume of sweating was measured in the fourth study, which found that the oxybutynin group had statistically significant reductions in sweating from baseline, whereas the placebo group did not.

Quality of life was assessed in 3 studies, which found that people treated with oxybutynin reported greater improvements compared with those treated with placebo; all differences between the groups were statistically significant.

The studies included in this evidence summary have many limitations. For example, all were small (range 32 to 140 participants), of short duration (2 to 6 weeks) and did not compare oxybutynin to other active treatments for hyperhidrosis.

Dry mouth was the most common adverse event reported across the studies. Other common adverse events were constipation, dry eyes and urinary retention.

NICE has not published a guideline on managing hyperhidrosis. However, the clinical knowledge summary on hyperhidrosis suggests systemic therapies, including oral antimuscarinics, as treatment options for people whose hyperhidrosis is not adequately managed through lifestyle modifications and antiperspirants.

A summary to inform local decision-making is shown in table 1.

Table 1 Summary of the evidence on effectiveness, safety, patient factors and resource implications

Effectiveness

In Schollhammer et al. (2015) (n=62), 60% of people taking oxybutynin had an improvement in Hyperhidrosis Disease Severity Scale (HDSS) score of 1 or more at 6 weeks compared with 27% taking placebo (p<0.01, statistically significant). It is unclear what level of improvement on the 4-point HDSS is considered clinically important.
In Wolosker et al. (2012) (n=50) 74% of people taking oxybutynin scored their improvement in palmar or axillary hyperhidrosis as 'moderate' or 'great' at 6 weeks compared with 27% taking placebo (p<0.001, statistically significant).
In Ghaleiha et al. (2012) (n=140), after 2 weeks, HDSS score improved by about 1.3 points in the oxybutynin group and about 0.8 points in the placebo group (p=0.03, statistically significant).
Costa Jr et al. (2014) (n=32) found people taking oxybutynin group had reductions in transepidermal water loss from baseline at 4 sites (all p<0.01, statistically significant), whereas people taking placebo did not.
Quality of life also improved significantly more with oxybutynin compared with placebo in the 3 RCTs (Schollhammer et al. 2015, Wolosker et al. 2012 and Costa Jr et al. 2014), For example, in Schollhammer et al. (2015), after 6 weeks, the mean improvement in validated, 30-point Dermatology Life Quality Index (DLQI) was 6.9 points in the oxybutynin group compared with 2.3 points in the placebo group (p<0.01, statistically significant). It is unclear if this improvement is clinically important.
The largest study by Ghaleiha et al. (2012) included people who were taking sertraline for major depressive disorder and it is unclear whether the results of this study apply to a more general population of people with hyperhidrosis.

Safety

The SPC states that adverse effects of oxybutynin are mainly due to its anticholinergic effects, with dry mouth reported most commonly.
The very common adverse events, occurring in 1 in 10 people or more, are constipation, nausea, dry mouth, dizziness, headache, somnolence, vision blurred and dry skin (SPC: oxybutynin).
Apart from dry mouth, oxybutynin was generally well tolerated in the studies.

Patient factors

The studies were small and short and it is unclear how well oxybutynin works for hyperhidrosis in the longer term. They also compared oxybutynin to placebo and we do not know how well oxybutynin works compared with other treatments for the condition.
Oxybutynin is available in a number of different formulations and some people may prefer one over another. However, only the standard-release tablets were used in the RCTs discussed in this evidence summary.
Adverse events, especially dry mouth, are common in people treated with oxybutynin. They may be minimised by using the lowest effective dose.
Many patients may prefer a topical treatment to risking the systemic adverse effects of an oral treatment. However, an oral treatment may be preferable to some other options, such as surgery.

Resource implications

The standard release tablet formulation of oxybutynin, which was used in the studies, is inexpensive (costing £1.15 to £1.49 for 56 tablets). Modified release tablets and transdermal patches are also available, but are more expensive (costing £13.77 to £27.20 per pack).
Oxybutynin tablets, at a daily dose of 2.5 mg to10 mg, cost between £0.62 and £1.60 for 30 days treatment (all prices taken from Drug Tariff, February 2017; excluding VAT).
The 30‑day cost of other oral antimuscarinics is £5.56 to £33.33 for propantheline bromide 15 mg to 90 mg daily (Drug Tariff, February 2017; excluding VAT) and £96.00 to £768.00 for glycopyrronium bromide oral solution (Sialanar) 1 mg to 8 mg daily (MIMS, February 2017; excluding VAT).