Pilocarpine drops for dry mouth in frail and life-limited patients: no clear benefit in an underpowered trial

Design

Double-blind, placebo-controlled randomised trial, Netherlands, 4 weeks

Population

92 adults with xerostomia (NRS 5 or more) and a life-limiting condition or frailty

Primary outcome

Mean change in xerostomia severity at 4 weeks

Effect

Adjusted difference at week 4 -0.37 (95% CI -1.31 to 0.58); no significant difference

A double-blind placebo-controlled trial at two hospitals and three nursing homes in the Netherlands randomised 92 adults with xerostomia of 5 or more on a 0 to 10 scale and a life-limiting condition or frailty, to four weeks of topical pilocarpine drops (44) or placebo (48).

There was no significant difference in xerostomia severity between groups at week 2 (adjusted beta 0.35, 95% CI -0.44 to 1.15) or week 4 (-0.37, -1.31 to 0.58). Both groups improved by about 1.4 to 1.5 points by week 2, but only the pilocarpine group improved further between weeks 2 and 4 (-0.86). Oral health-related quality of life was better with pilocarpine at two weeks (adjusted beta 2.8). Adverse effects were limited.

The trial recruited 92 of the 120 participants it needed, so it could have missed a real effect. A large improvement in the placebo group also shows how much dry mouth scores respond to attention alone.

• No significant difference in dry mouth severity at 2 or 4 weeks.
• Both groups improved early, including placebo.
• Only pilocarpine kept improving between weeks 2 and 4.
• The trial enrolled 92 of 120 planned participants.
• Tolerability was good, so a trial of drops is low risk where simple measures fail.

Why it matters

Dry mouth is a common distressing symptom with few treatments proven in this population.

Don't overread it

The primary result was null and the trial was underpowered, so the quality-of-life and week 2 to 4 findings are secondary and hypothesis-generating.

The statistics, in plain English

An interval of -1.31 to 0.58 on a 10-point scale excludes a very large benefit but not a modest one. When the placebo group improves by 1.4 points, a small real effect is hard to see against that noise.

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