Theophylline‐induced potentiation of the antinociceptive action of baclofen

Theophylline (35,50 mg/kg) potentiated the antinociceptive action of intraperitoneally administered baclofen in the tail flick and hot plate tests. Potentiation was most marked when the pretreatment time was 1 h, but some potentiation was still apparent following a 2 h pretreatment. Theophylline alone (50 mg/kg) produced only slight alterations in reaction latency in the two tests. When baclofen was applied directly into the spinal subarachnoid space, a 1 h pretreatment with theophylline produced minimal effects, but a 2 h pretreatment produced an increase in the antinociceptive action of baclofen. These results suggest that theophylline can potentiate the antinociceptive action of baclofen by actions at both supraspinal and spinal sites. 1983 British Pharmacological Society