Lack of photosensitising potential of tenidap, a novel anti-rheumatic agent.

1. The potential of orally administered tenidap sodium, a novel anti-rheumatic agent under investigation for the treatment of rheumatoid arthritis and osteoarthritis, to cause phototoxic reactions was investigated. 2. Twenty-four healthy volunteers entered a randomised, double-blind study in which they received tenidap sodium 40 mg or 120 mg or placebo daily for 7 days. The minimal erythema dose was determined using wavelengths of 305-460 nm for 3 days prior to drug administration and on the last 3 days of dosing. Appropriate clinical and laboratory tests were performed before, during and after the dosing period. 3. Tenidap did not have a statistically significant effect on immediate or delayed photosensitivity. No drug-related side effects were reported and there were no clinically significant adverse findings from the laboratory tests. 4. At the dosage and duration of tenidap sodium used, a photosensitising potential has not been demonstrated.