Prospidium chloride (prospidine) is a drug with cytostatic (alkylating) and anti-inflammatory properties. It has been studied for the treatment of rheumatoid arthritis. Prospidium chloride (prospidine) is a drug with cytostatic (alkylating) and anti-inflammatory properties. It has been studied for the treatment of rheumatoid arthritis. Chemically, it is a spiro compound.