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Chlorpheniramine Maleate / Phenylephrine Hydrochloride / Methscopolamine Nitrate

Pronunciation: klor-fen-AIR-uh-meen MAL-ee-ate/Fen-ill-EFF-rin HIGH-droe-KLOR-ide/meth-skoe-PAHL-uh-meen NYE-trate
Class: Antihistamine, Decongestant, Anticholinergic

Trade Names

AH-chew
- Tablets 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine

Dallergy
- Syrup 10 mg phenylephrine, 2 mg chlorpheniramine, 0.625 mg methscopolamine
- Tablets 10 mg phenylephrine, 4 mg chlorpheniramine, 1.25 mg methscopolamine
- Tablets 20 mg phenylephrine, 12 mg chlorpheniramine, 2.5 mg methscopolamine
- Tablets, chewable 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine

Dallergy PE
- Caplets 20 mg phenylephrine, 8 mg chlorpheniramine, 2.5 mg methscopolamine

Dehistine
- Syrup 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine

DriHist
- SR Tablets 20 mg phenylephrine, 8 mg chlorpheniramine, 2.5 mg methscopolamine

Duradryl
- Syrup 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine

Ex-Histine
- Syrup 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine

Extendryl
- Chewable Tablets 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine
- SR Tablets 20 mg phenylephrine, 8 mg chlorpheniramine, 2.5 mg methscopolamine
- Syrup 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine

NoHist Plus
- Chewable Tablets 10 mg phenylephrine, 2 mg chlorpheniramine, 1.25 mg methscopolamine

Omnihist L.A.
- Tablets 20 mg phenylephrine, 8 mg chlorpheniramine, 2.5 mg methscopolamine

Pre-Hist-D
- Tablets 20 mg phenylephrine, 8 mg chlorpheniramine, 2.5 mg methscopolamine

Rescon
- Tablets 40 mg phenylephrine, 12 mg chlorpheniramine, 1.25 mg methscopolamine

Pharmacology

Chlorpheniramine

Competitively antagonizes histamine at H 1 receptor sites.

Slideshow: 2014 Update - First Time Brand-to-Generic Switches

Phenylephrine

Stimulates postsynaptic alpha-receptors, resulting in vasoconstriction, which reduces congestion.

Methscopolamine

Competitively inhibits action of acetylcholine at muscarinic receptors.

Indications and Usage

Temporary relief of symptoms of allergic rhinitis, vasomotor rhinitis, sinusitis, and the common cold.

Contraindications

Hypersensitivity or idiosyncratic reaction to any ingredients of product; severe hypertension; severe coronary artery disease; narrow-angle glaucoma; urinary retention; hyperthyroidism; peptic ulcer; asthma attack; MAOI therapy or for 2 wk after stopping MAOI therapy; newborn or premature infants.

Dosage and Administration

Maximum Dose
Adults and Children 12 y of age and older

Chlorpheniramine 24 mg/day; phenylephrine 80 mg/day; methscopolamine 10 mg/day according to the prescribing information.

Children 6 to 11 y of age

Chlorpheniramine 12 mg/day; phenylephrine 40 mg/day; methscopolamine 5 mg/day according to the prescribing information.

Adults FDA-Approved Uses Symptoms of rhinitis, sinusitis, and the common cold Usual dosage

For specific dosing by product, see the above Product List.

Caplet

1 every 12 h.

Chewable tablets

1 to 2 tablets every 4 to 12 h.

ER tablets

1 to 2 tablets every 12 h.

Suspension

5 to 10 mL every 12 h.

Syrup

5 to 10 mL every 3 to 6 h.

Tablets

1 tablet every 4 to 6 h.

Maximum dose

Chlorpheniramine 24 mg/day; phenylephrine 80 mg/day; methscopolamine 10 mg/day.

Children FDA-Approved Uses Symptoms of rhinitis, sinusitis, and the common cold 12 y of age and older

For specific dosing by product, see the above Product List. See Adults for dosing.

Usual dosage Caplet

1 every 12 h.

Chewable tablets

1 to 2 tablets every 4 to 12 h.

ER tablets

1 to 2 tablets every 12 h.

Suspension

5 to 10 mL every 12 h.

Syrup

5 to 10 mL every 3 to 6 h.

Tablets

1 tablet every 4 to 6 h.

Maximum dose

Chlorpheniramine 24 mg/day; phenylephrine 80 mg/day; methscopolamine 10 mg/day.

6 to 11 y of age Usual dosage Caplets

As prescribed by health care provider.

For specific dosing by product, see the above Product List.

Chewable tablets

One-half to 1 tablet every 4 to 12 h.

ER tablets

One-half tablet every 12 h.

Suspension

2.5 to 5 mL every 12 h.

Syrup

2.5 to 5 mL every 4 to 6 h.

Tablets

One-half tablet every 4 to 6 h.

Maximum dose

Chlorpheniramine 12 mg/day; phenylephrine 40 mg/day; methscopolamine 5 mg/day.

Younger than 6 y of age

Safety and efficacy not established.

Elderly

Patients 60 y of age and older are more likely to exhibit adverse reactions. Per the Beers list, chlorpheniramine may have potent anticholinergic properties. Nonanticholinergic antihistamines are preferred in elderly patients when treating allergic reactions.

General Advice

  • Give with food or milk if GI upset occurs. Use a dosing spoon or syringe for pediatric doses of syrup. ER tablets may be broken in half, but should not be crushed or chewed.

Storage/Stability

Store at 69° to 77°F. Protect the syrup from freezing.

Drug Interactions

Alcohol, barbiturates (eg, phenobarbital), tricyclic antidepressants (eg, amitriptyline), other CNS depressants

Effects may be enhanced by chlorpheniramine.

MAOIs (eg, isocarboxazid)

May prolong and intensify the effects of chlorpheniramine and increase the effects of phenylephrine.

Mecamylamine, methyldopa, reserpine, veratrum alkaloids

Antihypertensive effects may be reduced by phenylephrine.

Laboratory Test Interactions

May interfere with diagnostic test results for skin tests using allergen extracts.

Adverse Reactions

Cardiovascular

Arrhythmias, CV collapse, hypertension, hypotension, palpitations, tachycardia.

CNS

Agitation, anxiety, CNS depression, CNS stimulation, confusion, convulsions, dizziness, drowsiness, fear, hallucinations, headache, insomnia, irritability, lassitude, nervousness, nightmares, restlessness, tenseness, tingling in hands or feet, trembling, tremor, unusual excitement, unusual tiredness, weakness.

Dermatologic

Increased sensitivity of the skin to sun, increased sweating, pallor, rash.

EENT

Blurred vision; nose, throat, and mouth dryness.

GI

Dry mouth, gastric irritability, gastric irritation, loss of appetite, stomach upset or pain, vomiting, nausea.

Genitourinary

Dysuria, urinary retention.

Miscellaneous

Blood dyscrasias, flushing, paradoxical reaction, respiratory difficulty, thickening of mucus.

Precautions

Monitor

Allergy symptoms

Assess for allergy symptoms (eg, rhinitis, nasal congestion, sneezing, itching, watery eyes) before and periodically throughout therapy.

CNS symptoms

Monitor patient for nervousness, dizziness, and insomnia. If noted, hold therapy and notify health care provider.

Excitability

Monitor children for antihistamine-induced excitability.


Pregnancy

Category C .

Lactation

Small amounts of sympathomimetic amines and antihistamines are excreted; use is not recommended.

Children

Safety and efficacy in children younger than 6 y of age not established. Antihistamines may cause excitability in children.

Elderly

Patients 60 y of age and older more likely to exhibit adverse reactions.

Special Risk Patients

Use with caution in patients with hypertension, heart disease, asthma, hyperthyroidism, increased IOP, diabetes mellitus, and prostatic hypertrophy.

Overdosage

Symptoms

Dry mouth, dilated pupils, hallucinations, severe hypertension, ventricular extrasystoles, short paroxysms of ventricular tachycardia, CNS depression, CNS stimulation, somnolence, convulsions, shock, death.

Patient Information

  • Review dosing schedule for prescribed dose form (eg, syrup, chewable tablet, extended-release tablet).
  • Advise caregiver to use dosing spoon or syringe when giving syrup to children.
  • Caution patient that extended-release tablet can be broken in half but that dose should be swallowed whole and not crushed or chewed.
  • Advise patient to take with food or milk if GI upset occurs.
  • Advise patient to take last dose late in the afternoon or early evening to reduce chance of drug causing sleeplessness.
  • Advise patient that if a dose is missed to take as soon as remembered unless it is nearing time for the next dose. Caution patient to not double the dose to catch up.
  • Advise patient that if allergy symptoms are not controlled, not to increase the dose of medication but to inform health care provider.
  • Caution patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
  • Advise patient to avoid alcohol and other CNS depressants because of risk of excessive sedation.
  • Caution patient not to take any OTC antihistamines or decongestants while taking this medication unless advised by health care provider.
  • If patient is to have allergy skin testing, advise to not take the medication for at least 6 days before the skin testing.
  • Instruct patient to stop taking drug and immediately report any of the following symptoms to health care provider: nervousness, dizziness, sleeplessness.

Copyright © 2009 Wolters Kluwer Health.

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