Medicines of choice in low back pain.

The marketed formulations of 6 analgesic preparations were compared in the treatment of patients suffering from acute exacerbations of low back pain using a crossover trial of balanced incomplete block design. Sixty out-patients with symptoms resulting from a mechanical or degenerative condition were each prescribed 3 drugs which were administered consecutively for 1 week each. The medications (and daily dosages) were coded as A --aspirin (3600 mg), B --dextropropoxyphene plus paracetamol (260 mg plus 2600 mg), C --indomethacin (150 mg), D --mefenamic acid (1500 mg), E --paracetamol (4000 mg), and F --phenylbutazone (300 mg). Daily pain scores were significantly lower (p less than 0.05) during treatment D than during treatments E and B, and significantly lower (p less than 0.05) during treatment A than during treatment B. There were large and significant differences between treatments in the percentages of recommended doses acceptable to the patients and in the number of defaults from the prescribed regimens. The patients chose F and D significantly more (p less than 0.05) often than A. Overall, there were consistently superior performances by mefenamic acid and phenylbutazone with little to choose between the two.