Gen-Allerate - General Information

A histamine H1 antagonist used in allergic reactions, hay fever, rhinitis, urticaria, and asthma. It has also been used in veterinary applications. One of the most widely used of the classical antihistaminics, it generally causes less drowsiness and sedation than promethazine. [PubChem]


Pharmacology of Gen-Allerate

In allergic reactions an allergen interacts with and cross-links surface IgE antibodies on mast cells and basophils. Once the mast cell-antibody-antigen complex is formed, a complex series of events occurs that eventually leads to cell-degranulation and the release of histamine (and other chemical mediators) from the mast cell or basophil. Once released, histamine can react with local or widespread tissues through histamine receptors. Histamine, acting on H1-receptors, produces pruritis, vasodilatation, hypotension, flushing, headache, tachycardia, and bronchoconstriction. Histamine also increases vascular permeability and potentiates pain. Gen-Allerate, is a histamine H1 antagonist (or more correctly, an inverse histamine agonist) of the alkylamine class. It competes with histamine for the normal H1-receptor sites on effector cells of the gastrointestinal tract, blood vessels and respiratory tract. It provides effective, temporary relief of sneezing, watery and itchy eyes, and runny nose due to hay fever and other upper respiratory allergies.


Gen-Allerate for patients

May cause excitability especially in children. Do not take this product unless directed by a physician, if you have a breathing problem such as emphysema or chronic bronchitis, or if you have glaucoma or difficulty in urination due to enlargement of the prostate gland. May cause drowsiness; alcohol, sedatives and tranquilizers may increase the drowsiness effect. Avoid alcoholic beverages, and do not take this product if you are taking sedatives or tranquilizers without first consulting your physician. Use caution when driving a motor vehicle or operating machinery.


Gen-Allerate Interactions

Substrate of CYP2D6 (minor), 3A4 (major); Inhibits CYP2D6 (weak).

Increased toxicity (CNS depression): CNS depressants, MAO inhibitors, tricyclic antidepressants, phenothiazines.

CYP3A4 inhibitors: May increase the levels/effects of chlorpheniramine. Example inhibitors include azole antifungals, ciprofloxacin, clarithromycin, diclofenac, doxycycline, erythromycin, imatinib, isoniazid, nefazodone, nicardipine, propofol, protease inhibitors, quinidine, and verapamil.


Gen-Allerate Contraindications

Hypersensitivity to chlorpheniramine maleate or any component of the formulation; narrow-angle glaucoma; bladder neck obstruction; symptomatic prostate hypertrophy; during acute asthmatic attacks; stenosing peptic ulcer; pyloroduodenal obstruction. Avoid use in premature and term newborns due to possible association with SIDS.


Additional information about Gen-Allerate

Gen-Allerate Indication: For the treatment of rhinitis, urticaria, allergy, common cold, asthma and hay fever.
Mechanism Of Action: Gen-Allerate binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine.
Drug Interactions: Donepezil Possible antagonism of action
Galantamine Possible antagonism of action
Rivastigmine Possible antagonism of action
Ethotoin The antihistamine increases the effect of hydantoin
Fosphenytoin The antihistamine increases the effect of hydantoin
Mephenytoin The antihistamine increases the effect of hydantoin
Phenytoin The antihistamine increases the effect of hydantoin
Food Interactions: Take with food.
Avoid alcohol.
Generic Name: Chlorpheniramine
Synonyms: Chloropheniramine; Chlorophenylpyridamin; Chlorophenylpyridamine; Chloroprophenpyridamine; Chlorphenamine; Chlorpheniramine Maleate; Chlorprophenpyridamine; Clorfeniramina; Dexchlorpheniramine; Dexchlorpheniramine Maleate
Drug Category: Anti-Allergic Agents; Antipruritics; Antihistamines
Drug Type: Small Molecule; Approved

Other Brand Names containing Chlorpheniramine: Aller-Chlor; Allergican; Allergisan; Antagonate; Chlo-Amine; Chlor-Trimeton; Chlor-Trimeton Allergy; Chlor-Trimeton Repetabs; Chlor-Tripolon; Chlorate; Chloropiril; Cloropiril; Efidac 24 Chlorpheniramine Maleate; Gen-Allerate; Haynon; Histadur; Kloromin; Mylaramine; Novo-Pheniram; Pediacare Allergy Formula; Phenetron; Piriton; Polaramine; Polaronil; Pyridamal 100; Telachlor; Teldrin;
Absorption: Well absorbed in the gastrointestinal tract.
Toxicity (Overdose): LD50 = 306 mg/kg in humans, mild reproductive toxin to women of childbearing age.
Protein Binding: 72%
Biotransformation: Primarily hepatic via Cytochrome P450 (CYP450) enzymes.
Half Life: 21-27 hours
Dosage Forms of Gen-Allerate: Tablet Oral
Tablet, extended release Oral
Syrup Oral
Chemical IUPAC Name: 3-(4-chlorophenyl)-N,N-dimethyl-3-pyridin-2-ylpropan-1-amine
Chemical Formula: C16H19ClN2
Chlorpheniramine on Wikipedia:
Organisms Affected: Humans and other mammals