Chlorphenamine


Generic Medicine Info
Indications and Dosage
Oral
Allergic conditions
Adult: 4 mg 4-6 hourly. Max: 24 mg daily.
Child: 1-2 years 1 mg bid. Max: 4 mg daily. 2-5 years 1 mg 4-6 hourly. Max: 6 mg daily. 6-12 years 2 mg 4-6 hourly. Max: 12 mg daily. >12 years Same as adult dose.
Elderly: Dose reduction may be needed. Max: 12 mg daily.

Parenteral
Allergic conditions
Adult: 10-20 mg via IM, SC or slow IV inj over 1 minute. Max: 40 mg daily.
Child: 1 month to 1 year 0.25 mg/kg. >1-5 years 2.5-5 mg. 6-12 years 5-10 mg. >12 years Same as adult dose.
Administration
May be taken with or without food.
Incompatibility
Incompatible with Ca chloride, kanamycin sulfate, noradrenaline acid tartrate, pentobarbital Na, and meglumine adipiodone.
Contraindications
Acute asthma, narrow-angle glaucoma, bladder neck obstruction, symptomatic prostate hypertrophy, stenosing peptic ulcer. Concomitant or within 14 days of MAOI use.
Special Precautions
Patient with epilepsy, increased intra-ocular pressure, glaucoma, prostatic hyperthrophy, severe CV disease (e.g. ischaemic heart disease, hypertension), urinary retention, pyloroduodenal obstruction, bronchitis, bronchiectasis, thyrotoxicosis. Children and elderly. Pregnancy and lactation.
Adverse Reactions
Significant: CNS depression.
Cardiac disorders: Palpitations, tachycardia.
Eye disorders: Blurred vision, diplopia.
Gastrointestinal disorders: Nausea, dry mouth, abdominal pain, diarrhoea.
General disorders and administration site conditions: Fatigue.
Investigations: Weight gain.
Metabolism and nutrition disorders: Anorexia.
Musculoskeletal and connective tissue disorders: Arthralgia.
Nervous system disorders: Sedation, disturbance in attention, abnormal coordination, dizziness, headache, excitability.
Psychiatric disorders: Somnolence.
Renal and urinary disorders: Urinary retention, polyuria.
Respiratory, thoracic and mediastinal disorders: Pharyngitis.
Patient Counseling Information
This drug may cause drowsiness, dizziness, blurred vision and psychomotor impairment, if affected, do not drive or operate machinery.
Overdosage
Symptoms: Sedation, paradoxical excitation of the CNS, toxic psychosis, apnoea, convulsions, dystonic reactions, cardiovascular collapse during arrhythmias. Management: Symptomatic and supportive treatment. May employ activated charcoal. Treat convulsions with IV diazepam. My use haemoperfusion in severe cases.
Drug Interactions
May enhance sedative effect of hypnotics, anxiolytics, sedatives, opioid analgesics and neuroleptics. May inhibit phenytoin metabolism which may lead to phenytoin toxicity.
Potentially Fatal: Increased anticholinergic effects with MAOIs.
Food Interaction
Increased CNS depression with alcohol.
Lab Interference
May react to skin test antigen, suppressing the wheal and flare reaction.
Action
Description: Chlorphenamine is an antihistamine which competitively inhibits histamine H1- receptor in the gastrointestinal and respiratory tract and blood vessels. Thus, prevents the release of histamine, prostaglandins and leukotrienes and prevents the migration of inflammatory mediators.
Synonym: Chlorpheniramine
Onset: Within 30 minutes.
Duration: 4-6 hours.
Pharmacokinetics:
Absorption: Readily absorbs from the gastrointestinal tract. Bioavailability: 25-50%. Time to peak plasma concentration: 2-3 hours.
Distribution: Widely distributed in the body and CNS. Enters breast milk. Volume of distribution: 6-12L/kg. Plasma protein binding: Approx 70%.
Metabolism: Undergoes extensive first-pass metabolism in the liver t by CYP450 enzymes to active and inactive metabolites.
Excretion: Via urine (22% as unchanged drug); faeces (trace amounts). Elimination half-life: 2-43 hours.
Chemical Structure

Chemical Structure Image
Chlorphenamine

Source: National Center for Biotechnology Information. PubChem Database. Chlorpheniramine, CID=2725, https://pubchem.ncbi.nlm.nih.gov/compound/Chlorpheniramine (accessed on Jan. 21, 2020)

Storage
Store below 25°C. Protect from light.
ATC Classification
R06AB04 - chlorphenamine ; Belongs to the class of substituted alkylamines used as systemic antihistamines.
References
Aller-Chlor Syrup (Rugby Laboratories). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 31/01/2019.

Aller-Chlor Tablets (Rugby Laboratories). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 31/01/2019.

Anon. Chlorpheniramine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 31/01/2019.

Buckingham R (ed). Chlorphenamine Maleate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 31/01/2019.

Chlorphenamine 10 mg/mL Solution for Injection (Synchrony Pharma Limited). MHRA. https://products.mhra.gov.uk/. Accessed 31/01/2019.

Disclaimer: This information is independently developed by MIMS based on Chlorphenamine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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