To the Editor: Bethanechol is a parasympathomimetic agent similar to acetylcholine that is known to be a selective stimulant of smooth muscle in the gastrointestinal tract and urinary bladder. It is normally used to treat non-obstructive urinary retention and has not previously been known to have any effect on skeletal muscle.

Adults with cerebral palsy usually slowly deteriorate over the years, with gradually increasing muscle tone, worsening speech, mobility difficulties and a loss of independence. There has been no change in their management for decades.

While working in a residential facility for adults with cerebral palsy, we serendipitously found that bethanechol significantly reduced the muscle spasticity in a patient for whom it was initially used to treat micturition difficulty.

Seven other patients who were wheelchair-bound with cerebral palsy were then progressively given bethanechol in increasing doses. All patients and/or their carers were advised that the medication was being used experimentally, and all consented to participate in a clinical trial. The results are summarised in the Box.

In all patients, bethanechol treatment was ceased for a week once the clinical benefits had been established, and all deteriorated during that week.

None of the patients suffered any detectable side effects from the use of bethanechol, but many were already taking a proton-pump inhibitor that may have protected them from any gastrointestinal adverse effects.

A synergistic interaction between bethanechol and another medication (eg, diazepam) was excluded as an explanation for the results obtained, as no other medication was common to all patients.

Bethanechol’s effect seems to be long-lasting, as the first patient has now been using it for 6 months with no deterioration in his improved muscle tone.

A Medline search revealed no studies in which bethanechol had been used as a treatment for cerebral palsy. Although our sample was very small, the fact that every patient improved indicates that a larger trial of bethanechol for cerebral palsy is warranted.