Fig. 1From: Tolerability and efficacy of a combination of paracetamol and caffeine in the treatment of tension-type headache: a randomised, double-blind, double-dummy, cross-over study versus placebo and naproxen sodiumTime course of the mean pain intensity difference (PID) for the three investigational treatments (intention-to-treat dataset, n = 91). PCF paracetamol 1,000 mg + caffeine 130 mg; NAP naproxen sodium 550 mg, PLA placeboBack to article page