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 We sought unpublished studies by asking personal contacts and searching online clinical trial registers and manufacturers’ websites.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.
Data collection and analysis
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.
Plain language summary
Oral ketoprofen for treatment of acute episodic tension-type headache in adults
This review found that few people with 2 to 14 tension-type headaches a month get good pain relief from taking ketoprofen 25 mg. There are questions about how studies of this type of headache are conducted. These questions involve the type of people chosen for the studies and the types of outcomes reported. This limits the usefulness of the results, especially for people who just have an occasional headache.
People with frequent episodic tension-type headache have between 2 and 14 headaches days every month. Tension-type headache stops people concentrating and working properly, and results in much disability. When headaches do occur, they get better over time, even without treatment.
Ketoprofen is a commonly used painkiller, available by prescription in most parts of the world but without prescription (over-the-counter) in some. The usual dose is 25 mg or 50 mg taken by mouth.
In May 2016, we searched the medical literature and found four studies involving 1253 participants looking at ketoprofen for frequent episodic tension-type headache. Only a fraction of the participants were involved in comparisons between ketoprofen 25 mg and placebo (a dummy tablet). Results were usually reported two hours after taking the medicine or placebo. The International Headache Society recommends the outcome of being pain-free two hours after taking a medicine, but other outcomes are also suggested. Few studies reported these recommended outcomes, so there was limited information to analyse for some outcomes.
The outcome of being pain-free at two hours was reported by 27 in 100 people taking ketoprofen 25 mg, and in 16 out of 100 people taking placebo, meaning that only 11 in 100 people benefited because of ketoprofen 25 mg (low quality evidence). The outcome of being pain-free or having only mild pain at two hours was reported by 66 in 100 people taking ketoprofen 25 mg, and in 38 out of 100 people taking placebo (moderate quality evidence), meaning that 28 in 100 people benefited because of ketoprofen 25 mg.
About 14 in 100 people taking ketoprofen 25 mg reported having a side effect, which was slightly more than with placebo (7 in 100 people) (low quality evidence). Most side effects were mild or moderate in intensity. No side effects were serious.
Ketoprofen 25 mg was not different from paracetamol 1000 mg for any measure of headache relief (moderate and low quality evidence), but was associated with more side events (low quality evidence).
Quality of the evidence
The quality of the evidence for being pain-free at two hours was low quality, and for having mild pain at two hours was moderate quality. Moderate quality evidence means that we are reasonably confident about the results. Low quality evidence means that we are not very certain about the results and they could change with more information.