MYOCLONIC SPASMS FOLLOWING INTRATHECAL DIAMORPHINE

The use of intrathecal diamorphine via an implanted portal system is d escribed for pain control in a patient suffering from vertebral metast atic disease. The complication of myoclonic spasms affecting the lower half of the body occurred after 14 days, when increasing the bolus do se to 40 mg. The spasms lasted for 3 hr and then gradually subsided. D iamorphine was subsequently restarted at a lower dose of 15 mg twice d aily. On increasing the dose to 20 mg diamorphine 10 days later, sever e distressing myoclonic spasms recurred 20 min postinjection. Myoclonu s could only be controlled by instituting a local anesthetic intrathec al block. The patient was finally managed with 20 mg diamorphine per d ay by intrathecal infusion, and the pain was reasonably well controlle d for the following 10 weeks without any recurrence of myoclonic spasm s.