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

Several clinical trials have demonstrated that low doses of non-steroidal anti-inflammatory drugs relieve episodic tension-type headache (ETH).

The aims of this placebo-controlled study were to determine whether single doses of diclofenac-K 12.5 and 25mg effectively relieve ETH in adults and to compare it to ibuprofen 400mg.

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 12.5mg (n=160), diclofenac-K 25mg (n=156), ibuprofen 400mg (n=151) and placebo (n=153). The primary efficacy variable was total pain relief, calculated as the time-weighted sum of the pain relief assessments from baseline to the 3h evaluation time (TOTPAR-3).

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), > or =50%maxTOTPAR at 3 and 6h, weighted pain intensity difference at 3 and 6h (SPID-3; SPID-6), percentage of patients with complete headache relief at 2h, end of study global evaluation and time to rescue medication. The number-needed-to-treat (NNT) at 6h was 4.5 (2.9-9.2) in the ibuprofen 400mg group, 4.0 (2.8-7.3) in the diclofenac-K 12.5mg group and 3.9 (2.7-7.1) in the diclofenac-K 25mg group. These differences were not statistically significant.

Diclofenac-K, administered as single doses of 12.5 and 25mg effectively relieves ETH and is comparable to ibuprofen 400mg.