Phenytoin as a coanalgesic in cancer pain

• Published in: Journal of pain and symptom management Vol. 7; no. 4; pp. 209 - 213
• Main Authors: Yajnik, Sudarshan, Singh, Gyan Prakash, Singh, Gurmeet, Kumar, Mukesh
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.1992; Elsevier Science
• Subjects: Adult; Analgesics; Anticonvulsants; Biological and medical sciences; buprenorphine; Buprenorphine - administration & dosage; Buprenorphine - therapeutic use; cancer pain; Drug Therapy, Combination; Female; Humans; Male; Medical sciences; Middle Aged; Neoplasms - physiopathology; Neuropharmacology; Nursing; Pain - diagnosis; Pain - drug therapy; Pain - etiology; Pharmacology. Drug treatments; phenytoin (PHT); Phenytoin - administration & dosage; Phenytoin - therapeutic use; cancer pain; Anticonvulsants; phenytoin (PHT); buprenorphine; Human; Drug combination; Chemotherapy; Pain; Treatment; Anticonvulsant; Malignant tumor; Narcotic analgesic
• ISSN: 0885-3924; 1873-6513
• DOI: 10.1016/0885-3924(92)90077-U

The efficacy of phenytoin (PHT), buprenorphine (Bu), and Bu + PHT for the relief of cancer pain of various etiologies was evaluated in a randomized, double-blind study of 3 groups, each comprised of 25 patients. Treatment duration was 1 month. PHT (100 mg by mouth twice daily) provided >50% pain relief to 18 patients (72%) and >75% relief to 4 (16%). Bu (0.2 mg sublingually twice daily) gave 21 patients (84%) >50% relief and 15 patients (60%) >75% relief. Of the Bu-treated patients, 8 had major side effects, while none of the PHT-treated patients experienced significant untoward reactions. Combined therapy (PHT, 50 mg PO + Bu 0.1 mg SL twice daily) provided >50% pain relief to 22 patients (88%) and >75% to 18 (72%); only 3 patients experienced a significant side effect. This study suggests that phenytoin has mild-to-moderate pain-relieving properties of its own and can significantly enhance buprenorphine analgesia. By permitting a lower opioid dose, it may reduce the occurrence of opioid-related side effects. PHT's lack of serious side effects, as well as its documented anxiolytic and antidepressant actions, may add to its comparative usefulness. Further clinical trials of PHT as a coanalgesic and/or adjuvant agent in cancer pain are warranted.