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Rizatriptan in treatment of migraine

Clinical bottom line

Rizatriptan is effective for treating acute migraine attacks. It generates relief of pain, and from nausea, photophobia, phonophobia and functional disability.


Reference

MD Ferrari et al. Meta-analysis of rizatriptan efficacy in randomized controlled clinical trials. Cephalalgia 2001 21: 129-136.

Review

This review consisted of information from seven randomised trials performed by Merck an completed by end 1998. The authors were given information from the studies by the company, and two of the authors are from Merck. The studies were phase 3 efficacy studies, and five had been published.

There were 2068 patients given rizatriptan 10 mg, 1486 given rizatriptan 5 mg, and 1260 given placebo. All patients (actually 99%) had moderate or severe pain when tablets were taken, and migraine was diagnosed using IHS criteria.

The review reports on a number of outcomes for pain over the first two hours, and on sustained outcomes over 24 hours. It also reports on the recovery from nausea, photophobia, phonophobia and functional disability in those patients suffering these at the start of a treatment. Only information from a first attack was taken if the trials had crossover design.

Results

This paper is exceptional for having lots of useful numbers and different outcomes. For simplicity, graphs of the percentage of patients achieving the outcome over time will be given where appropriate.

Headache response

Headache response is where pain originally moderate or severe becomes mild or disappears. Results for rizatriptan and placebo over two hours are shown in Figure 1. At two hours, the number needed to treat with rizatriptan 10 mg compared with placebo to achieve one patient with a headache response was 3.0 (95%CI 2.8 to 3.4).

Figure 1: Headache response over two hours



Sustained response

This response is defined by patients who have a headache response at two hours, and then who have no recurrence nor take any additional medicines for headache within the next 22 hours. This outcome occurred for 18% of patients with placebo and 37% with rizatriptan 10 mg, producing an NNT of 5.3 (4.6 to 6.2).

Pain free

Results for rizatriptan and placebo over two hours are shown in Figure 2. At two hours, the number needed to treat with rizatriptan 10 mg compared with placebo to achieve one patient who was pain free was 3.2 (3.0 to 3.5).

Figure 2: Pain free patients over two hours





Sustained pain free

This response is defined by patients who were pain free at two hours, and then who had no recurrence nor take any additional medicines for headache within the next 22 hours. This outcome occurred for 7% of patients with placebo and 25% with rizatriptan 10 mg, producing an NNT of 5.5 (4.9 to 6.4).

Elimination of nausea

This outcome applied to people who were nauseated when they took their medicine for migraine, and in whom the nausea was relieved. Results for rizatriptan and placebo over two hours are shown in Figure 3. At two hours, the number needed to treat with rizatriptan 10 mg compared with placebo to achieve one patient who was not nauseated was 4.8.

Figure 3: Elimination of nausea over two hours




Elimination of photophobia

This outcome applied to people who had photophobia when they took their medicine for migraine, and in whom the photophobia was relieved. Results for rizatriptan and placebo over two hours are shown in Figure 4. At two hours, the number needed to treat with rizatriptan 10 mg compared with placebo to achieve one patient who did not have photophobia was 3.6.

Figure 4: Elimination of photophobia over two hours





Elimination of phonophobia

This outcome applied to people who had phonophobia when they took their medicine for migraine, and in whom the phonophobia was relieved. Results for rizatriptan and placebo over two hours are shown in Figure 5. At two hours, the number needed to treat with rizatriptan 10 mg compared with placebo to achieve one patient who did not have phonophobia was 3.8.

Figure 5: Elimination of phonophobia over two hours

Elimination of functional disability

This outcome applied to people who had functional disability when they took their medicine for migraine, and in whom the functional disability was relieved (scored at zero on a four point scale). Results for rizatriptan and placebo over two hours are shown in Figure 6. At two hours, the number needed to treat with rizatriptan 10 mg compared with placebo to achieve one patient who did not have functional disability was 4.0.

Figure 6: Elimination of functional disability over two hours



Comment

This is an absolutely cracking paper that gives so much useful detail, the sort of information that can only be derived from trials at the individual patient level. It also makes one realise how much different outcomes matter to different people. Is it pain relief? If so how much, and when? Is it photophobia, or nausea, or just being able to function? If it's any of those, this paper has the answer for rizatriptan. It is so curious that such information has to wait until years after the drug has been available to see information like this, when it should be available at launch.

It also makes one think about hurdles and outcomes. Some are harder to achieve than others. For instance, a headache response at two hours will be less easy to achieve than pain free at two hours and without needing any more tablets nor having any more headache. Figure 7 shows results for four pain outcomes, and how the responses with placebo and with rizatriptan 10 mg. Fewer folk can clear the higher hurdles.

Figure 7: Different pain outcomes