Chloropyramine is a first generation H1 antagonist. It is used for allergic eye and nasal symptoms, bronchial asthma, Quincke’s edema, and allergic reactions to food, medications and insect bites. It is available in several European countries as an oral or IV/IM preparation for emergent situations. It has the typical anticholinergic side effects seen in older H1 antihistamines. It is available under several names, including Allergosan, Suprastin, Supralgon and Avapena, in several countries, including Georgia, Hungary, Lithuania, Latvia, Russia, Croatia, Serbia, Bosnia and Herzegovina, Bulgaria and Mexico.
Chlorpheniramine is a first generation H1 alkylamine antihistamine. It is less sedating than other first generation antihistamines. It is sometimes used off label as an antidepressant and anti-anxiety medication as it has serotonin-norepinephrine reuptake inhibiting properties. It is available alone and in various combinations in the US, Canada, throughout Europe and Asia.
Chlorphenoxamine, more commonly known as Systral, is a medication with structural similarities to diphenhydramine. It is mostly used as an anti-Parkinsonian drug and is available in Latin American and Caribbean countries, as well as some European countries and Thailand.
Cinnarizine is an H1 antagonist that functions as both an antihistamine and also as a calcium channel blocker. It is a piperazine derivative. It improves blood flow to the brain and is used for cerebral apoplexy, cerebral symptoms following trauma and cerebral arteriosclerosis. It is also used for nausea and vomiting due to several causes. It is also antiserotinergic and antidopaminergic. Due to its action of dopamine receptors, it can cause parkinsonism if used frequently. It is not available in the US or Canada, but is available under a number of names in many countries, including Brazil, Peru, Philippines, Malaysia, China, Bangladesh, India, and Israel, among several others.
Clemastine is an H1 anthistamine. Though it can be sedating, it has fewer side effects than several other H1 medications. It is also a functional inhibitor of acid sphingomyelinase. It is available in many countries without prescription under brand names such as Tavist, Tavegil or Agasten. It is particularly effective for itching.
Cyclizine is an H1 antihistamine mostly used for nausea, vomiting and dizziness from motion sickness or medications, such as anesthesia. It is also used to potentiate the effects of opiates and opioids. It is a piperazine derivative and is available in the US and UK as IM/IV and oral formulations.
Cyproheptadine is a first generation H1 antihistamine. It is also antiserotonergic and for this reason is used to manage serotonin syndrome. It has a variety of unusual uses, including as a local anesthetic, to treat nightmares in children and due to PTSD, for hyperhidrosis, and to prevent migraine.
Dexbrompheniramine is a widely available medication with structural similarities to chlorpheniramine. It is used to manage general allergic symptoms. It is available in the US and Canada as Drixoral.
Dexchlorpheniramine is the one form of the drug chlorpheniramine. It is available in the US and Canada as Polaramine.