Chlorpheniramine Maleate

Chlorphenamine (CP, CPM), also known as chlorpheniramine, is an antihistamine used to treat the symptoms of allergic conditions such as allergic rhinitis (hay fever). It is taken by mouth. The medication takes effect within 6 hours and lasts for about a day. Common side effects include sleepiness, restlessness, and weakness. Other side effects may include dry mouth and wheeziness. Its is a first-generation antihistamine and works by blocking the H1 receptor. Chlorphenamine was patented in 1948 and came into medical use in 1949. It is available as a generic medication and over the counter. Chlorphenamine is often combined with phenylpropanolamine to form an allergy medication with both antihistamine and decongestant properties, though phenylpropanolamine is no longer available in the US after studies showed it increased the risk of stroke in young women. Chlorphenamine remains available with no such risk. Chlorphenamine may be combined with the opioid hydrocodone. Chlorphenamine/dihydrocodeine immediate-release syrups are also marketed. The antihistamine is helpful in cases where allergy or common cold is the reason for the cough; it is also a potentiator of opioids, allowing enhanced suppression of cough, analgesia, and other effects from a given quantity of the drug by itself. In various places in the world, cough and cold preparations containing codeine and chlorphenamine are available. In the drug Coricidin, chlorphenamine is combined with the cough suppressant dextromethorphan.