The addition of glyceryltrinitrate to capsaicin cream reduces the thermal allodynia associated with the application of capsaicin alone in humans.
The aim of this study was to determine whether topical application of capsaicin cream causes thermal allodynia and the extent to which this is attenuated by the addition of glyceryltrinitrate (GTN). This was a double blind placebo controlled study of 40 consenting adult subjects. Each of four cream combinations (GTN, capsaicin, GTN/capsaicin and vehicle) were applied to the subjects with at least a 1 day interval between each application. Water at a known temperature was applied to the standard area of skin where cream had been applied. Subjects rated the resulting thermal allodynia using a 0-10 Likhert score. Thermal allodynia is usually apparent when warm water is applied to skin containing capsaicin. The thermal allodynia caused by the topical application of capsaicin was significantly reduced by the addition of GTN. The addition of GTN to capsaicin cream significantly reduces the thermal allodynia associated with the application of capsaicin cream alone.
Walker
R A
RA
Rampark Pain Centre, Northern Ireland, Lurgan, UK.
McCleane
G J
GJ
D002211:Capsaicin / Q000008:administration & dosage* / Q000009:adverse effects* / Q000494:pharmacology; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D006801:Humans; D005996:Nitroglycerin / Q000008:administration & dosage / Q000627:therapeutic use*; D009824:Ointments; D010146:Pain / Q000139:chemically induced* / Q000188:drug therapy*; D013696:Temperature; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*
D009824:Ointments; D014665:Vasodilator Agents; D005996:Nitroglycerin; D002211:Capsaicin