Sixty-five patients attending a
pain relief clinic were randomly allocated to treatment for 5 weeks with
amitriptyline alone,
distigmine alone,
amitriptyline and
distigmine started together, or addition of
distigmine to preexisting treatment with
amitriptyline. Forty-eight patients successfully completed the trial; the most common cause for withdrawal was dry mouth in the
amitriptyline-alone group. Two parameters were measured:
Pain intensity was measured at the beginning and end of the treatment, and the saliva flow was measured at the beginning and the end of the treatment. At the end of 5 weeks, treatment with a combination of
amitriptyline (75 mg/day) and
distigmine (10 mg/day) resulted in a 43% reduction of
pain and no subjectively noticeable
mouth dryness.
Distigmine alone also decreased
pain and increased saliva flow, sometimes to the point of discomfort, whereas
amitriptyline alone, in this particular series, did not significantly reduce
pain and produced unpleasant
mouth dryness. The addition of
distigmine to preexisting (and ineffective)
amitriptyline treatment failed to relieve
pain. We therefore conclude that a combination of
amitriptyline and
distigmine (both given ab initio) may be a useful
therapy for
chronic pain.