Abstract: The invention provides the use of a compound of formula (I) wherein R1 and R2 independently represent H or C1-C6 alkyl, or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for the treatment of dermatological disorders; peripheral neuropathies; arthritis; gastrointestinal or urogenital diseases; headache associated with substances or their withdrawal; tension headache; pediatric migraine; post-traumatic dysautonomic cephalgia; orofacial pain; allergic or chronic obstructive airways diseases; glaucoma or ocular inflammation; or prophylaxis of migraine.