Two patients suffering with severe
pain due to metastatic
abdominal neoplasm were selected to examine whether subarachnoid
neostigmine provided effective
pain relief.
Neostigmine was injected through a
catheter introduced into the subarachnoid space at L4-L5. Patients were monitored for changes in arterial blood pressure, cardiac and respiratory rates, body temperature, level of consciousness and neurologic change.
Pain was classified by the patients on a verbal four-grade scale, and
analgesia was classified on a verbal three-grade scale. Complete
pain relief was obtained 2 h after
neostigmine (0.2 mg) in one patient and 4 h after
neostigmine (0.1 mg) in the second patient.
Pain of mild intensity returned 20 and 22 h after
drug administration, respectively. Gastrointestinal discomfort was observed in both cases, but
nausea and
vomiting occurred only in the patient treated with the highest dose of
neostigmine. No significant change in the monitored parameters was observed, except for a 6-h period of decreased blood pressure in the patient treated with the lower dose of
neostigmine which required no specific treatment. The results obtained in these anecdotal cases indicate that subarachnoid
neostigmine may provide
analgesia in patients with
pain arising from
neoplasia, but further studies using controlled trials are needed before the
drug is brought into clinical use.