Reference
Cianchetti C. Capsaicin jelly against migraine pain. Int J Clin Pract 2010;64:457-459.
Design
Randomized single-blinded clinical trial
Participants
23 migraineurs (mean age 25 years) all experiencing pain with pressure applied to arteries on the scalp (even in the absence of an attack) and all not experiencing auras before attacks
Study Medication and Dosage
0.1% capsaicin cream or a placebo cream was applied in minimal amounts (0.05–0.10 ml per artery) topically to painful arteries in the absence of a migraine attack. For those who reported a >50% reduction in pain, a second experiment was conducted in which topical capsaicin or the placebo was administered during a migraine attack. Subjects received treatments in a randomized order.
Outcome Measures
Subjective reports of pain were noted 30 minutes after application of the cream. If the initial response was a >50% pain reduction, the other treatment (placebo or capsaicin) was not used. If, however, the initial treatment was <50% effective, it was washed off and replaced with the opposite treatment.
Key Findings
In the absence of a migraine, 17 of 23 subjects (15/20 females and 2/3 males) reported a >50% reduction in arterial pain (versus 2 of 23 with placebo). This decrease in pain occurred in 10 to 30 minutes after application. During mild to moderate migraines, 11 of 17 reported a >50% reduction in pain with capsaicin. Even if we assume total treatment failure in all 6 of the subjects who did not report >50% pain reduction in the first phase of the trial, the treatment would still have helped 48% (11 of 23).
Practice Implications
Topical capsaicin can deplete Substance P and related pain-transmitting peptides, rendering the peripheral nervous system incapable of communicating pain from cell to cell.
Topical capsaicin can deplete Substance P and related pain-transmitting peptides, rendering the peripheral nervous system incapable of communicating pain from cell to cell. The author of the new report reminds us that perivascular afferent fibers of the superficial temporal artery are involved in migraine pain and these fibers contain Substance P and related peptides. All this suggests that localized treatments might help migraineurs.
Through as-yet unpublished evidence observed by the author of the new trial, more than 60% of migraineurs experience scalp arterial pain in response to topical pressure applied even in the absence of an attack (versus >80% during a migraine headache). This observation inspired the methodology used in the initial phase of the trial.
Previous capsaicin research used intranasal applications in migraineurs, a route of administration that causes burning sensations.1 Thus, by avoiding intranasal use while still producing efficacy, the current trial breaks new ground.
A majority of migraineurs are female. Indeed in the new report 20 of 23 subjects were women. While 15 of those 20 women in the trial were significantly helped, 2 of the 3 male migraineurs also obtained benefit.
On a final note, if you wish to institute therapeutic trials with patients, make sure to use rubber gloves in applying the capsaicin cream. Rubbing an eye with a finger that has touched the cream, even if that finger has been carefully washed, can cause moderate to severe burning pain.
