Displaying 3 results of Cloperastine Stable Isotopes Cloperastine is a cough suppressant drug that works by blocking the cough reflex in the brain. Stable isotopes of cloperastine are non-radioactive isotopes that have the same number of protons and electrons as the regular version of the drug, but a different number of neutrons. These isotopes are used in research and drug development to study the metabolism and pharmacokinetics of cloperastine in the body.