Quinine dihydrochloride is an antiparasitic used to treat malaria and is particularly important for managing malaria during the first trimester of pregnancy. It inhibits Slo3 (KCa 5.1) channel, which are a significant part of the mammalian KSper (sperm potassium conductance), by binding to hydrophobic side chains located at the intracellular region of the channel pore.