Low-dose diclofenac potassium in the treatment of episodic tension-type headache

Background Several clinical trials have demonstrated that low doses of non-steroidal anti-inflammatory drugs relieve episodic tension-type headache (ETH). Aims. The aims of this placebo-con trolled study were to determine whether single doses of diclofenac-K 12.5 and 25 mg effectively relieve ETH in adults and to compare it to ibuprofen 400mg. Methods. A single-dose multicentre, randomised, double-blind, double-dummy, clinical trial was conducted at 22 primary care centres in Germany. All subjects had a history of ETH according to the classification of the International Headache Society. Of 684 subjects randomised, 620 used the study drugs for an episode of tension headache occurring within one month after enrolment: diclofenac-K 12.5 mg (n = 160), diclofenac-K 25 mg (n = 156), ibuprofen 400mg (n 151) and placebo (it = 153). The primary efficacy variable was total pain relief, calculated as the time-weighted sum of the pain relief assessments from baseline to the 3 h evaluation time (TOTPAR-3). Results. For TOTPAR-3, all active treatments were superior to placebo; no statistically significant difference between the three active treatments could be detected. A similar pattern was also observed with regard to TOTPAR-6 (6h evaluation time), greater than or equal to50%maxTOTPAR at 3 and 6 h, weighted pain intensity difference at 3 and 6h (SPID-3; SPID-6), percentage of patients with complete headache relief at 2 h, end of study global evaluation and time to rescue medication. The number-needed-to-treat (NNT) at 6 h was 4.5 (2.9-9.2) in the ibuprofen 400 mg group, 4.0 (2.8-7.3) in the diclofenac-K 12.5 mg group and 3.9 (2.7-7.1) in the diclofenac-K 25 mg group. These differences were not statistically significant. Conclusion. Diclofenac-K, administered as single doses of 12.5 and 25 mg effectively relieves ETH and is comparable to ibuprofen 400 mg. (C) 2002 European Federation of Chapters of the International Association for the Study of Pain. Published by Elsevier Science Ltd. All rights reserved.