Title: Chlorpheniramine
CAS Registry Number: 132-22-9
CAS Name: g-(4-Chlorophenyl)-N,N-dimethyl-2-pyridinepropanamine
Additional Names: 2-[p-chloro-a-(2-dimethylaminoethyl)benzyl]pyridine; 1-(p-chlorophenyl)-1-(2-pyridyl)-3-dimethylaminopropane; 1-(p-chlorophenyl)-1-(2-pyridyl)-3-N,N-dimethylpropylamine; 3-(p-chlorophenyl)-3-(2-pyridyl)-N,N-dimethylpropylamine; g-(4-chlorophenyl)-g-(2-pyridyl)propyldimethylamine; chlorprophenpyridamine; chlorphenamine
Trademarks: Haynon (Rosemont)
Molecular Formula: C16H19ClN2
Molecular Weight: 274.79
Percent Composition: C 69.93%, H 6.97%, Cl 12.90%, N 10.19%
Literature References: Synthesis: Sperber et al., US 2567245, US 2676964 (1951, 1954, both to Schering). Prepn of d-form: L. A. Walter, US 3061517 (1962 to Schering). Solutions: Foley, Ilavsky, US 2766174 (1956 to Schering). Pharmacology: F. E. Roth, W. M. Govier, J. Pharmacol. Exp. Ther. 124, 347 (1958). Toxicity data: R. B. Smith et al., Toxicol. Appl. Pharmacol. 28, 240 (1974). Comprehensive description: C. G. Eckhart, T. McCorkle, Anal. Profiles Drug Subs. 7, 43-80 (1978).
Properties: Oily liquid, bp1.0 142°.
Boiling point: bp1.0 142°
Derivative Type: Maleate
CAS Registry Number: 113-92-8
Trademarks: Allergisan (Pharmacia); Chlor-Trimeton (Schering-Plough); Piriton (GSK); Teldrin (SKB)
Molecular Formula: C16H19ClN2.C4H4O4
Molecular Weight: 390.86
Percent Composition: C 61.46%, H 5.93%, Cl 9.07%, N 7.17%, O 16.37%
Properties: Crystals, mp 130-135°. uv max (water): 261 nm (e 5760). Soly in mg/ml at 25°: ethanol 330; chloroform 240; water 160; methanol 130. Slightly sol in benzene, ether. pH of a 2% aq soln about 5. LD50 orally in mice: 162 mg/kg (Smith).
Melting point: mp 130-135°
Absorption maximum: uv max (water): 261 nm (e 5760)
Toxicity data: LD50 orally in mice: 162 mg/kg (Smith)
Derivative Type: d-Form
CAS Registry Number: 25523-97-1
Additional Names: Dexchlorpheniramine; d-chlorpheniramine
Properties: Oily liquid. [a]D25 +49.8° (c = 1 in DMF).
Optical Rotation: [a]D25 +49.8° (c = 1 in DMF)
Derivative Type: d-Form maleate
CAS Registry Number: 2438-32-6
Trademarks: Phenamin (Nycomed); Polamin (Schering-Plough); Polaramine (Schering-Plough); Polaronil (Schering-Plough)
Properties: Crystals from ethyl acetate, mp 113-115°. [a]D25 +44.3° (c = 1 in dimethylformamide). pH of 1% soln 4-5.
Melting point: mp 113-115°
Optical Rotation: [a]D25 +44.3° (c = 1 in dimethylformamide)
Therap-Cat: Antihistaminic.
Therap-Cat-Vet: Antihistaminic.
Keywords: Antihistaminic; Alkylamine Derivatives.
Chlorphenoxamide Chlorphenoxamine Chlorphentermine Chlorproethazine Chlorproguanil

Systematic (IUPAC) name
Clinical data
Trade names Chlor-trimeton
AHFS/ monograph
MedlinePlus a682543
Pregnancy cat. A (AU) B (US)
Legal status Pharmacist Only (S3) (AU) OTC (UK) OTC (US)
(for oral forms)
Routes Oral, IV, IM, SC
Pharmacokinetic data
Bioavailability 25 to 50%
Protein binding 72%
Metabolism Hepatic (CYP2D6)
Half-life 21–27 hours
Excretion Renal
CAS number 132-22-9 YesY
ATC code R06AB04
PubChem CID 2725
IUPHAR ligand 1210
DrugBank DB01114
ChemSpider 2624 YesY
UNII 3U6IO1965U YesY
KEGG D07398 YesY
ChEBI CHEBI:52010 YesY
Chemical data
Formula C16H19ClN2 
Mol. mass 274.788 g/mol
Physical data
Solubility in water 0.55 g/100 mL, liquid mg/mL (20 °C)
 YesY (what is this?)  (verify)

Chlorphenamine (INN) or chlorpheniramine (USAN, former BAN), commonly marketed in the form of chlorpheniramine maleate (Chlorphen-12[1]), is a first-generation alkylamine antihistamine used in the prevention of the symptoms of allergic conditions such as rhinitis and urticaria. Its sedative effects are relatively weak compared to other first-generation antihistamines. Chlorphenamine is one of the most commonly used antihistamines in small-animal veterinary practice. Although not generally approved as an antidepressant or anti-anxiety medication, chlorphenamine appears to have these properties as well.[2] [3]

Chlorphenamine is part of a series of antihistamines including pheniramine (Naphcon) and its halogenated derivatives and others including fluorpheniramine, dexchlorpheniramine (Polaramine), brompheniramine (Dimetapp), dexbrompheniramine (Drixoral), deschlorpheniramine, dipheniramine (also known as triprolidine with the trade name Actifed), and iodopheniramine.

The halogenated alkylamine antihistamines all exhibit optical isomerism, and chlorphenamine in the indicated products is racemic chlorphenamine maleate, whereas dexchlorpheniramine is the dextrorotary stereoisomer.