The effect of intranasal cocaine and lidocaine on nitroglycerin-induced attacks in cluster headache.

The administration of nitroderivatives in cluster headache (CH) sufferers is the most reproducible experimental paradigm to induce spontaneous-like pain attacks. Previous uncontrolled studies have reported that the local use of anaesthetic agents in the area of the sphenopalatine fossa is able to extinguish nitroglycerin (NTG)-induced pain in CH. The present study, carried out according to a double-blind placebo-controlled design, included 15 CH patients, six with episodic CH (mean +/- SD age of 36.8+/-5.6 years), and nine with chronic CH (37.8+/-10.4 years). Patients had undergone a standard NTG test (0.9 mg sublingually), during which the intensity of pain was scored using a visuoanalogic scale (VAS, range 0-10). Nine patients (two with the episodic form, seven with the chronic form) experienced a typical, spontaneous-like attack on the usual side, occurring in all cases within 45 min. In these patients, the test was repeated with an interval of 2 days, and once pain intensity reached 5 on the VAS, a 10% solution of cocaine hydrochloride (1 ml, mean amount per application 40-50 mg), or 10% lidocaine (1 ml), or saline was applied using a cotton swab in the area corresponding to the sphenopalatine fossa, under anterior rhinoscopy. This was done in both the symptomatic and the non-symptomatic side, for 5 min. Treatments were always performed randomly, in separate sessions. All patients responded promptly to both anaesthetic agents, with complete cessation of induced pain occurring after 31.3+/-13.1 min for cocaine and 37.0+/-7.8 min for lidocaine (M+/-SD). In the case of saline application, pain severity increased thereafter, and extinction of the provoked attacks occurred with a latency of 59.3+/-12.3 min (P<0.01 and P<0.01 vs. cocaine and lidocaine, respectively, Mann-Whitney U-test). While further suggesting that the sphenopalatine ganglion participates in the mechanisms of pain, these findings indicate that the local administration of the anaesthetic agents cocaine and lidocaine is effective on NTG-induced CH attacks, and may be used in the symptomatic treatment of this disorder.