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The drug also blocked production by COX-1 of prostacyclin , a member of a family of potent , hormone-like substances called prostaglandins that play a role in a wide variety of physiological functions including pain , inflammation and , presumably , cancer . In subsequent studies , Brookhaven collaborations found that the drug effectively blocked test animals ' craving for nicotine , heroin , alcohol and methamphetamine . Norwegian company seeking to develop a male birth control pill has signed a licensing agreement with the University of Massachusetts Medical School covering research that could lead to a drug to block sperm 's ability to swim and fertilize an egg .... In his study , the drug completely blocked HIV infection in a mouse model . Primaquine , another anti-malaria drug , blocks transmission of the parasite after 24 hours .