Scopolamine-induced Migraine Like Headache

Objective Scopolamine butylbromide (SB), a muscarinic receptor antagonist, is used commonly in gastric X-ray examination in the physical check-up in Japan. This study describes clinical features of SB-induced headache. Patients and Methods SB-induced headache was defined as headache that started within 20 minutes after intramuscular administration of SB (20 mg/body). The Primary and the secondary headaches were diagnosed according to the ICHD-II criteria. SB-induced headache was classified as headache induced by acute substance use or that due to exposure (ICHD-II code 8.1). Clinical features and background of subjects with SB-induced headache were analyzed. We also estimated the frequency of SB-related headache between migraineurs and non-migraineurs. Results A total of 54 subjects (39 women and 15 men) experienced SB-induced headache. All subjects had the present history of migraine. Nine subjects had ≥2 times of the headache. Mean age (SD) was 46.2 (9.7) years [46.2 (9.7) for women and 46.3 (10.0) for men]. Clinical hallmarks of headache showed that pulsating / throbbing pain occurred in diffuse or bilateral head sites. Headache worsened at 20-30 minutes from the onset and persisted for 6-18 hours, and ameliorated gradually 8 hours later. All subjects had repeated nausea and vomiting. Severity of headache revealed severe degree requiring complete bed rest in 50 subjects (92.6%). SB-induced headache had similar characteristics as migraine without aura (MO) attacks. Liver and renal functions were normal in all SB-related migraineurs. They had no allergic history of medication and food. In 1,865 non-migraine controls, one healthy subject had a mild degree of migraine like headache triggered by SB injection. Conclusion SB triggers a severe degree MO like headache or worsens pre-existing migraine in some migraineurs. SB-induced headache could contribute to disequilibrium between acetylcholine and other neuropeptides. We should use SB more carefully as it can be an aggravating drug of migraine.