Lucy Veys, Sheena Derry, R Andrew Moore

Tension-type headache (TTH) affects about 1 person in 5 worldwide. It is divided into infrequent episodic TTH (fewer than one headache day per month), frequent episodic TTH (2 to 14 headache days per month), and chronic TTH (15 headache days a month or more). Ketoprofen is one of a number of analgesics suggested for acute treatment of headaches in frequent episodic TTH. To assess the efficacy and safety of ketoprofen for treatment of episodic TTH in adults compared with placebo or any active comparator. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and the Oxford Pain Relief Database up to May 2016, and also reference lists of relevant published studies and reviews. We sought unpublished studies by asking personal contacts and searching online clinical trial registers and manufacturers' websites. We included randomised, double-blind, placebo-controlled studies (parallel-group or cross-over) using oral ketoprofen for symptomatic relief of an acute episode of TTH. Studies had to be prospective, with participants aged 18 years or over, and include at least 10 participants per treatment arm. Two review authors independently assessed studies for inclusion and extracted data. We used the numbers of participants achieving each outcome to calculate the risk ratio (RR) and number needed to treat for one additional beneficial outcome (NNT) or one additional harmful outcome (NNH) for oral ketoprofen compared to placebo or an active intervention for a range of outcomes, predominantly those recommended by the International Headache Society (IHS).We assessed the evidence using GRADE and created a 'Summary of findings' table. We included four studies, all of which enrolled adults with frequent episodic TTH. They all specified using the IHS diagnostic criteria and reported mean baseline pain of at least moderate intensity. While 1253 people with TTH participated in these studies, the numbers available for any analysis were lower than this because outcomes were inconsistently reported and because many participants received active comparators.None of the included studies were at low risk of bias across all domains considered, although for most studies and domains this was likely to be due to inadequate reporting rather than poor methods. We judged one study to be at high risk of bias due to small size.Useful information was available only for ketoprofen 25 mg. For the IHS preferred outcome of being pain-free at two hours the NNT for ketoprofen 25 mg compared with placebo was 9.0 (95% confidence interval (CI) 4.8 to 72) in two studies (272 participants; low quality evidence). The NNT was 3.7 (95% CI 2.6 to 6.3) for pain-free or mild pain at two hours in two studies (272 participants; moderate quality evidence). Fewer people needed rescue medication with ketoprofen 25 mg than with placebo, with a number needed to treat to prevent one event (NNTp) of 6.2 (95% CI 4.3 to 11) in three studies (605 participants; moderate quality evidence). The number of participants reporting any adverse event was higher with ketoprofen 25 mg than placebo (NNH 15, (95% CI 8.7 to 45)) in three studies (651 participants with 66 events; low quality evidence). Most events were of mild to moderate intensity.Ketoprofen 25 mg was not different from paracetamol 1000 mg in two studies with 276 participants for any efficacy outcomes (low to moderate quality evidence); the RR for pain-free at two hours was 1.3 (95% CI 0.9 to 2.0). The number of participants reporting any adverse event was higher with ketoprofen 25 mg than with paracetamol (NNH 17, 95% CI 8.9 to 130)) in two studies (582 participants, 68 events; low quality evidence).Studies reported no serious adverse events.We judged the quality of the evidence comparing ketoprofen 25 mg with placebo or paracetamol 1000 mg as moderate to very low. Where evidence was downgraded it was because of the small number of studies and events. Ketoprofen 25 mg provided a small benefit compared with placebo in terms of being pain-free at two hours or having mild or no pain at two hours for people with frequent episodic TTH who have an acute headache of moderate or severe intensity. Its use was associated with more people experiencing adverse events. Ketoprofen 25 mg was not superior to paracetamol 1000 mg for any efficacy outcome.