The experimental drug ziconotide, a synthetic form of sea snail venom, can relieve refractory pain in people with cancer or acquired immunodeficiency syndrome (AIDS), researchers report. In a study of 111 patients, ziconotide achieved significant analgesia in people whose pain hadn't responded to morphine or other analgesics.
The patients studied had significant pain from either cancer or AIDS. Researchers randomly assigned them to receive either intrathecal ziconotide or a placebo over a 10-day treatment period. Measured by patient ratings, pain relief was moderate to complete in 53% of patients who received ziconotide, compared with 18% of patients who received a placebo.
Adverse effects of ziconotide, including dizziness and confusion, were common but manageable with dosage adjustments. Not yet approved by the Food and Drug Administration, the drug could become commercially available later this year.
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"Intrathecal Ziconotide in the Treatment of Refractory Pain in Patients with Cancer or AIDS," JAMA, P. Staats, et al., January 7, 2004.