Dipyridamole as an Antiviral Agent

We described the pyrimido-pyrimidine derivative dipyridamole (DP) as an interferon (IFN) inducer in cultivated in vitro lymphoid cells, administrated orally in mice and in humans attaining high IFN titres within 24 hours. An IFN antagonistic period was recorded. Gut-associated lymphoid tissue was identified as the inducer target. Three double-blind placebo trials were carried out, involving more than 6000 participants. The results proved that DP acts as a prophylactic for influenza and viral acute respiratory diseases. Experimental evidence proved that the IFN-inducing activity of DP is due to its capacity to inhibit cAMP phosphodiesterase. Additionally, DP demonstrates a marked inhibitory effect on the replication of a broad spectrum of viruses belonging to various taxonomic groups. Contradictory results were obtained concerning DP’s IFN-synthesis in humans. A pharmacokinetic model and analysis convincingly explained the lack of DP-induced IFN production in humans. DP activities were followed and described in lupus erythematosus, common cold, chronic pulmonary diseases, liver diseases, ophthalmology, dermatology (herpesvirus and papillomavirus infections) and AIDS. Special attention was given to DP’s effect in blood aggregation.