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Pilocarpine as an adjuvant to morphine therapy

1998; Elsevier BV; Volume: 351; Issue: 9099 Linguagem: Inglês

10.1016/s0140-6736(05)78339-2

1474-547X

Sebastiano Mercadante,

Pain Mechanisms and Treatments

Morphine is the preferred strong opioid analgesic for cancer pain. However, opioid-related side effects cause therapeutic problems. Adjuvant treatment is commonly prescribed. Pilocarpine is a cholinergic agonist which exerts a broad spectrum of pharmacological effects with predominant muscarinic action. A 64-year-old man had a lung cancer invading his chest wall that had progressed after surgical intervention, despite chemotherapy and radiotherapy. His pain had been treated with morphine 90 mg daily with a partial pain relief, but he had nausea, hallucinations, dry mouth, sedation, constipation, and urinary retention requiring temporary urinary catheterisation. While nausea and hallucinations disappeared after some days with haloperidol 2 mg daily, his other symptoms persisted and worsened during treatment with amitriptyline in an attempt to reduce the morphine dose. Xerostomia was the most disturbing symptom. Oral candidiasis and other infections were excluded. Pilocarpine treatment (15 mg daily of a 2% solution of pilocarpine by mouth in three divided doses) was tried before reducing the morphine or switching to another opioid. As a result, his dry mouth was better tolerated and difficulties in speaking, chewing, and swallowing were improved. Constipation, urinary retention, and sedation also improved and intermittent urinary catheterisation was no longer necessary. Symptom control was effective using the same doses of pilocarpine even with increased doses of morphine. There are no published studies on the use of cholinergic agonists as adjuvants during morphine treatment. Pilocarpine has been reported to relieve complaints of oral dryness due to different causes in almost 90% of patients without causing notable side effects. A clear association between the use of morphine and dryness of the mouth has been shown, although the mechanism for this effect is unclear. The disappearance of urinary retention observed after pilocarpine administration is likely to be due to the enhancement of the tone and mobility of the bladder, reduced by opioids. Pilocarpine may have improved Performance Scale (KPS). We assumed that a KPS score of 70 or more was acceptable, as the patients would be at least able to care for themselves at home. 25 patients scored 70 or more preoperatively, 12 less. All the patients were studied by computed tomography or magnetic resonance imaging, or both. Tumour size and peritumourous oedema were evaluated as hypothetical prognostic factors. The results were evaluated upon discharge and after 6 months, a period that was arbitrarily assumed as sufficient for neurological recovery. The differences between preoperative KPS (KPS 0), discharge KPS (KPS 1), and follow-up KPS (KPS 2) were computed and matched with the Wilcoxon paired test to assess the impact of the following factors on outcome: tumour location and size, peritumourous oedema, ASA grading, and preoperative neurological conditions. There were four perioperative deaths (10·8%) due to irreversible postoperative brain oedema (two), myocardial infarction (one), or progressive neurological deterioration (one). Those who died shared a preoperative KPS of 50 and three of them had a grade III ASA classification. Follow-up data were obtained in 32 of the survivors. KPS 0 of 70 or more was significantly related to good or excellent outcome is reassured by an increase in KPS scores (table). Tumour size, location, and peritumourous oedema were, by themselves, not significant, but may influence preoperative neurological conditions. Although not significant, the patients graded as ASA III fared worse than the others. We suggest that surgery should be offered to very old patients with intracranial meningiomas, because their quality of life can be improved in a high percentage of cases,