Modulation of central sensitisation by detoxification in MOH: results of a 12-month detoxification study

Human and animal models suggest that central sensitisation plays a role in medication-overuse headache (MOH). We aimed to study pain perception in MOH patients before and a year after withdrawal.

We examined pain perception in 35 MOH patients before and two, six and 12 months after detoxification. For baseline comparison, we tested 40 healthy controls. We measured cephalic and extra-cephalic pressure-pain thresholds and supra-threshold pressure-pain scores and extra-cephalic pain thresholds, supra-threshold pain scores and temporal summation for electrical stimulation.

Of the 35 patients, 21 patients completed the entire study and remained cured of MOH. Statistically significant differences between patients and healthy controls were found in cephalic pressure-pain thresholds (137.3 kPa vs. 170 kPa, P < 0.05), extra-cephalic pressure pain thresholds (213.3 vs. 274.3 kPa, P < 0.05), in cephalic supra-threshold pressure-pain scores measured on a 100 mm visual analogue scale (61 vs. 27 mm, P < 0.05) and extra-cephalic supra-threshold pain scores for electrical stimulation (19.0 vs. 10.0 mm, P < 0.05). Cephalic supra-threshold pain scores decreased statistically significantly from 50.3 mm at baseline to 28.0 mm at the 12-month follow-up. In contrast to controls, temporal summation was not found in MOH patients before withdrawal, but after detoxification temporal summation normalised.

The central nervous system is sensitised in patients with MOH. For the first time we demonstrate that the pain perception continues to normalise up to a year after detoxification. This emphasises the importance of detoxification and follow-up to prevent relapse.