To the Editor.—
We read with interest in the Archives the article written by DiGiovanna and Blank, who were unable to detect any benefit of lysine hydrochloride (400 mg three times a day) in the prevention of recurrent herpes simplex infection.1 Recently, we carried out a similar study whose results strongly suggest a dose-dependent effect of this drug.
Patients and Method.—
Identical-in-appearance lysine hydrochloride and mannitol capsules (250 mg each) were randomly given on a double-blind basis to 31 patients suffering from at least four annual (average 9.7) episodes of herpes simplex labialis or genitalis. During the first trimester, patients were given two capsules twice a day. Eighteen of them completed another trimester with one capsule in the morning and two at night.Patients recorded severity and duration of each recurrence. They were seen after three and six months. To determine the effect of therapy on suppressing herpes outbreaks,