Purpose: Though thalidomide in a dosage of 100 mg/day is the standard treatment for recurrent oral and genital ulcers (OGU), its toxicity would be less important with lower dosage, while its efficacy would be identical. Furthermore, duration of treatment might be a major risk factor for the development of subsequent polyneuropathy. To determine the dosage of thalidomide leading to the best efficacy/toxicity ratio, a pilot study was conducted from 1993 to 1996.
Methods: Seventeen patients with OGU (mean age: 43 years, sex-ratio: 12:5) were included in the study and presented either recurrent oral ulcerations (8 patients), oro-genital ulcerations (3 patients), Behçet disease (4 patients), or recurrent OGU associated with leukemia (2 patients). The initial dosage of thalidomide was 50 mg/day (1 tablet) for 1 month. If the patient's condition improved, the dosage was reduced to one tablet every other day for 1 month and one tablet every 3 days thereafter. Nerve conduction studies (EMG) were performed at inclusion in the study and every 6 months thereafter.
Results: Among the 17 patients, remission was observed in ten patients within the first month of treatment and the condition of seven patients improved. Complete remission was observed in six patients after a 2-month treatment and in one patient after 4 months. A 200-mg/8 days dosage induced prolonged remission in 12 patients. Among them, ten patients received a 150-mg dosage over 8 days thereafter and disease relapsed in four of them. Among the six patients who received a 100-mg dosage over 8 days, only one relapse was observed. EMG showed a decrease in sensory nerve action potentials in six patients after 8 months and a half on average. Only three patients had to discontinue their treatment due to the occurrence of either paresthesia (2 patients) or areflexia (1 patient). Our study shows that initially a 50-mg/day dose is efficacious in the treatment of OGU and that administration of one tablet every 2 or 3 days is efficacious in more than 60% of the patients to maintain remission.
Conclusion: A dosage of 50 mg/day is initially efficacious in most cases, provided that the patient is carefully followed up to allow early detection of potential peripheral neuropathy.