Inhibition of skin reactivity by antihistamines.

A number of studies have explored the inhibition of antigen-induced skin hypersensitivity reactions by the newer, nonsedating antihistamines such as terfenadine. The collective results of these studies indicate that this inhibitory effect begins within two hours of the administration of a single dose of terfenadine and within three to four days of a single dose of astemizole. Offset of this effect occurs within forty-eight hours of cessation of terfenadine therapy and four weeks or more after the withdrawal of astemizole. The time of onset and offset of this inhibitory effect is indicative of the period of clinical activity of these drugs and thus may be a relevant consideration in selecting an appropriate therapeutic regimen.

Anti-inflammatory activity of the steroid alkaloid glycoside, toatine.

1. Tomatine, isolated from extracts of crown gall-infected tomato plants or obtained commercially, was tested for anti-inflammatory activity using three different methods.2. Tomatine administered to intact rats intramuscularly in a dose range of 1-10 mg/kg or orally in doses of 15-30 mg/kg exerted a significant dose dependent inhibition of carrageenan induced paw oedema. The inhibitory effect of tomatine when given in a dose of 10 mg/kg intramuscularly to intact rats lasted more than 24 hr.3. In adrenalectomized rats significant dose-related inhibition of paw oedema was obtained with tomatine and the inhibition at each dose level (0.5-10 mg/kg) was found to be greater than that found in intact animals.4. Tomatine administered subcutaneously to intact rats daily for 7 days in doses of 5 or 10 mg/kg exerted a significant, dose dependent inhibition of granulation tissue formation induced by the subcutaneous implantation of carrageenan impregnated cotton pellets.5. Tomatine administered to intact mice in a dose of 10 mg/kg subcutaneously 1 hr before the intraperitoneal injection of acidified saline and intravenous pontamine sky blue significantly decreased the leakage of the protein bound dye into the peritoneal cavity.6. Tomatidine, the aglycone of tomatine, was not effective at dose levels of 10-20 mg/kg in any of the three tests.