Action of a new non-steroid anti-inflammatory drug, carprofen (Ro 20-5720) on activation of the complement system: an in vitro research.

Carprofen (Ro 20-5720), DL-6-chloro-alpha-methyl-carbazole-2-acetic acid, is a new non-steroid anti-inflammatory drug. We have studied the possible in vitro interference of the drug with the activation of human complement system. Carprofen exerts a constant inhibitory action of immunohaemolysis at a concentration of 4.5 X 10(-4)M. At the same concentration the drug is able to prevent the activation of the alternate pathway induced by insulin. Its specific site of action is on C1 and C3 components activation, according to the inhibiting activity on both classic and alternate pathway. However at a lower dosage (7.5 X 10(-6)M) carprofen is able to display an inducing action on the alternate pathway, thus confirming the complex in vitro interferences of the drug with the complement system.