Beta-carboline derivatives for use as analgesics

Pharmaceutical compositions comprising a compound of formula (1), wherein n = 2, 3 or 4; Z is an ester group of formula R3-O-CO- wherein R3 is C1-6 alkyl or C2-6 alkenyl; R1, R2 and R5 are, independently, halogen, H, OH, CF3, OMe, NO2; and R4 = H or C1-6 alkyl, are useful in the treatment of pain, trauma, spasticity and movement disorder other than that resulting from epilepsy. The compounds may be in free base form or in the form of an acid addition salt, such as the hydrochloride salt. Compounds according to formula (1) are inhibitors of the uptake of GABA (gamma-amino-butyric acid) by the GABA transporter protein GAT-3/4.