Monocaprin and doxycycline as a treatment for cold sores

Objectives: The study objective was to investigate the antiviral and wound-healing effect of a hydrogel containing either monocaprin or a combination of monocaprin and a low dose of doxycycline in vivo against herpes labialis. Methods: Subjects were divided into two groups: (i) with prodromal symptoms of cold sore; (ii) with a vesicle. Both groups applied the hydrogel five times a day for five days. Test formulations were: (i) hydrogel containing monocaprin and doxycycline (MCD), (ii) hydrogel containing only monocaprin (MC) and (iii) placebo hydrogel. Formulations were distributed randomly to subjects within each group. Subjects recorded treatment results in a 6-day diary and a 7 day follow-up diary to evaluate treatment outcomes. Results: For the MCD group the mean time to healing was 5.5 days (prodromal) and 5.1 days (vesicles/ulceration). This was significantly shorter than for the placebo groups, (7.25 and 7.5 days respectively; p<0.05). Pain relief, recorded with an analog scale during the treatment period, was significantly more with MCD (combining both the prodromal and vesicle groups) than with the MC and placebo groups (p=0.0114). Conclusion: Combining monocaprin with low-dose doxycycline offers effective treatment for cold sores, significantly reducing time to healing and pain compared with the placebo and monocaprin alone. The latter had some effect though not reaching significance. Reformulation of the monocaprin preparation may make it possible to enhance activity

Support: Icelandic Research Council;IADR/GlaxoSmithKline Award 2005.