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Chlorpheniramine

Pronunciation

Pronunciation

(klor fen IR a meen)

Index Terms

  • Chlorphenamine
  • Chlorpheniramine Maleate
  • CTM

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Liquid, Oral, as maleate:

Ed ChlorPed: 2 mg/mL (60 mL) [contains fd&c red #40, propylene glycol, saccharin sodium, sodium benzoate; cotton candy flavor]

Syrup, Oral, as maleate:

Aller-Chlor: 2 mg/5 mL (120 mL) [contains alcohol, usp, fd&c yellow #6 (sunset yellow), menthol, methylparaben, propylene glycol, propylparaben]

Aller-Chlor: 2 mg/5 mL (118 mL [DSC]) [contains alcohol, usp, fd&c yellow #6 (sunset yellow), menthol, methylparaben, propylene glycol, propylparaben; fruit flavor]

Chlor-Trimeton: 2 mg/5 mL (120 mL) [contains alcohol, usp]

Ed Chlorped Jr: 2 mg/5 mL (118 mL, 473 mL) [alcohol free, sugar free; contains fd&c red #40, methylparaben, propylene glycol, propylparaben; cherry flavor]

Tablet, Oral, as maleate:

Aller-Chlor: 4 mg [scored; contains fd&c yellow #10 aluminum lake]

Allergy: 4 mg [contains fd&c yellow #10 (quinoline yellow)]

Allergy: 4 mg [contains fd&c yellow #10 aluminum lake]

Allergy: 4 mg [scored; contains fd&c yellow #10 aluminum lake]

Allergy 4 Hour: 4 mg [DSC] [contains fd&c yellow #10 (quinoline yellow)]

Allergy Relief: 4 mg [contains fd&c yellow #10 aluminum lake]

Allergy-Time: 4 mg [contains fd&c yellow #10 aluminum lake]

Chlor-Trimeton: 4 mg [scored]

Chlorphen: 4 mg [scored; contains fd&c yellow #10 (quinoline yellow)]

Ed-Chlortan: 4 mg [scored; contains fd&c yellow #10 aluminum lake]

Pharbechlor: 4 mg

Generic: 4 mg

Tablet, Oral, as tannate:

Ed-Chlor-Tan: 8 mg [DSC]

Tablet Extended Release, Oral, as maleate:

Chlor-Trimeton Allergy: 12 mg [contains fd&c blue #2 aluminum lake, fd&c yellow #10 aluminum lake, fd&c yellow #6 aluminum lake]

Chlor-Trimeton Allergy: 12 mg [contains fd&c yellow #6 (sunset yellow), fd&c yellow #6 aluminum lake]

Generic: 12 mg

Brand Names: U.S.

  • Aller-Chlor [OTC]
  • Allergy 4 Hour [OTC] [DSC]
  • Allergy Relief [OTC]
  • Allergy [OTC]
  • Allergy-Time [OTC]
  • Chlor-Trimeton Allergy [OTC]
  • Chlor-Trimeton [OTC]
  • Chlorphen [OTC]
  • Ed Chlorped Jr [OTC]
  • Ed ChlorPed [OTC]
  • Ed-Chlor-Tan [DSC]
  • Ed-Chlortan [OTC]
  • Pharbechlor [OTC]

Pharmacologic Category

  • Alkylamine Derivative
  • Histamine H1 Antagonist
  • Histamine H1 Antagonist, First Generation

Pharmacology

Competes with histamine for H1-receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract

Distribution

Vd: Children and Adolescents 6 to 16 years: 7 ± 2.8 L/kg (Simons 1982); Adults: 6-12 L/kg (Paton 1985)

Metabolism

Hepatic via CYP450 enzymes (including CYP2D6 and other unidentified enzymes) to active and inactive metabolites; significant first-pass effect (Sharma 2003)

Excretion

Urine (Sharma, 2003)

Time to Peak

Children and Adolescents 6 to 16 years: Oral : 2.5 ± 1.5 hours (range: 1 to 6 hours) (Simons 1982); Adults: 2-3 hours (Sharma 2003)

Half-Life Elimination

Serum: Children and Adolescents 6 to 16 years: 13.1 ± 6.6 hours (range: 6.3 to 23.1 hours) (Simons 1982); Adults: 14-24 hours (Paton 1985)

Protein Binding

33% (range: 29% to 37%) (Martínez-Gómez 2007)

Use: Labeled Indications

Perennial and seasonal allergic rhinitis and other allergic symptoms including urticaria

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.

OTC labeling: When used for self-medication, do not use to make a child sleep

Dosing: Adult

Allergic symptoms, allergic rhinitis: Oral: Chlorpheniramine maleate:

Immediate release: 4 mg every 4-6 hours; do not exceed 24 mg/24 hours

Extended release: 12 mg every 12 hours; do not exceed 24 mg/24 hours

Dosing: Pediatric

Allergic symptoms, allergic rhinitis: Oral: Chlorpheniramine maleate:

Immediate release:

Children 2-5 years: 1 mg every 4-6 hours; do not exceed 6 mg/24 hours

Children 6-11 years: 2 mg every 4-6 hours; do not exceed 12 mg/24 hours

Children ≥12 years: Refer to adult dosing.

Extended release: Children ≥12 years: Refer to adult dosing.

Administration

May be administered with food or water. Timed release oral forms are to be swallowed whole, not crushed or chewed.

Dietary Considerations

May be taken with food or water. Some products may contain phenylalanine.

Storage

Protect from light.

Drug Interactions

Abiraterone Acetate: May increase the serum concentration of CYP2D6 Substrates. Management: Avoid concurrent use of abiraterone with CYP2D6 substrates that have a narrow therapeutic index whenever possible. When concurrent use is not avoidable, monitor patients closely for signs/symptoms of toxicity. Consider therapy modification

AbobotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of AbobotulinumtoxinA. Monitor therapy

Acetylcholinesterase Inhibitors: May diminish the therapeutic effect of Anticholinergic Agents. Anticholinergic Agents may diminish the therapeutic effect of Acetylcholinesterase Inhibitors. Monitor therapy

Aclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Ajmaline: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Monitor therapy

Amphetamines: May diminish the sedative effect of Antihistamines. Monitor therapy

Analgesics (Opioid): Anticholinergic Agents may enhance the adverse/toxic effect of Analgesics (Opioid). Specifically, the risk for constipation and urinary retention may be increased with this combination. Monitor therapy

Anticholinergic Agents: May enhance the adverse/toxic effect of other Anticholinergic Agents. Monitor therapy

Asunaprevir: May increase the serum concentration of CYP2D6 Substrates. Consider therapy modification

Azelastine (Nasal): CNS Depressants may enhance the CNS depressant effect of Azelastine (Nasal). Avoid combination

Benzylpenicilloyl Polylysine: Antihistamines may diminish the diagnostic effect of Benzylpenicilloyl Polylysine. Management: Suspend systemic H1 antagonists for benzylpenicilloyl-polylysine skin testing and delay testing until systemic antihistaminic effects have dissipated. A histamine skin test may be used to assess persistent antihistaminic effects. Consider therapy modification

Betahistine: Antihistamines may diminish the therapeutic effect of Betahistine. Monitor therapy

Blonanserin: CNS Depressants may enhance the CNS depressant effect of Blonanserin. Consider therapy modification

Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Buprenorphine: CNS Depressants may enhance the CNS depressant effect of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine patches (Butrans brand) at 5 mcg/hr in adults when used with other CNS depressants. Consider therapy modification

Cannabis: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Cimetropium: Anticholinergic Agents may enhance the anticholinergic effect of Cimetropium. Avoid combination

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Monitor therapy

Cobicistat: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

CYP2D6 Inhibitors (Moderate): May decrease the metabolism of CYP2D6 Substrates. Monitor therapy

CYP2D6 Inhibitors (Strong): May decrease the metabolism of CYP2D6 Substrates. Consider therapy modification

Darunavir: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Dimethindene: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. Monitor therapy

Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (e.g., opioids, barbiturates) with concomitant use. Consider therapy modification

Eluxadoline: Anticholinergic Agents may enhance the constipating effect of Eluxadoline. Avoid combination

Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Consider therapy modification

Fosphenytoin-Phenytoin: Chlorpheniramine may increase the serum concentration of Fosphenytoin-Phenytoin. Monitor therapy

Gastrointestinal Agents (Prokinetic): Anticholinergic Agents may diminish the therapeutic effect of Gastrointestinal Agents (Prokinetic). Monitor therapy

Glucagon: Anticholinergic Agents may enhance the adverse/toxic effect of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Avoid combination

Glycopyrrolate (Oral Inhalation): Anticholinergic Agents may enhance the anticholinergic effect of Glycopyrrolate (Oral Inhalation). Avoid combination

Hyaluronidase: Antihistamines may diminish the therapeutic effect of Hyaluronidase. Management: Patients receiving antihistamines (particularly at larger doses) may not experience the desired clinical response to standard doses of hyaluronidase. Larger doses of hyaluronidase may be required. Consider therapy modification

HYDROcodone: CNS Depressants may enhance the CNS depressant effect of HYDROcodone. Management: Consider starting with a 20% to 30% lower hydrocodone dose when using together with any other CNS depressant. Dose reductions in the other CNS depressant may also be warranted. Consider therapy modification

HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Imatinib: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Ipratropium (Oral Inhalation): May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Itopride: Anticholinergic Agents may diminish the therapeutic effect of Itopride. Monitor therapy

Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Levosulpiride: Anticholinergic Agents may diminish the therapeutic effect of Levosulpiride. Avoid combination

Lumefantrine: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce adult dose of CNS depressant agents by 50% with initiation of concomitant methotrimeprazine therapy. Further CNS depressant dosage adjustments should be initiated only after clinically effective methotrimeprazine dose is established. Consider therapy modification

MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Monitor therapy

Mianserin: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

Minocycline: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Mirabegron: Anticholinergic Agents may enhance the adverse/toxic effect of Mirabegron. Monitor therapy

Mirtazapine: CNS Depressants may enhance the CNS depressant effect of Mirtazapine. Monitor therapy

Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

OnabotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of OnabotulinumtoxinA. Monitor therapy

Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination

Oxatomide: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

OxyCODONE: CNS Depressants may enhance the CNS depressant effect of OxyCODONE. Management: When oxycodone is combined with another CNS depressant, a dose reduction of one or both agents should be considered. The extended release oxycodone starting dose should be reduced 50% to 67% when initiated in patients already receiving CNS depressants. Consider therapy modification

Panobinostat: May increase the serum concentration of CYP2D6 Substrates. Management: Avoid concurrent use of sensitive CYP2D6 substrates when possible, particularly those substrates with a narrow therapeutic index. Consider therapy modification

Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination

Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates. Peginterferon Alfa-2b may increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Perampanel: May enhance the CNS depressant effect of CNS Depressants. Management: Patients taking perampanel with any other drug that has CNS depressant activities should avoid complex and high-risk activities, particularly those such as driving that require alertness and coordination, until they have experience using the combination. Consider therapy modification

Perhexiline: CYP2D6 Substrates may increase the serum concentration of Perhexiline. Perhexiline may increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Piribedil [INT]: CNS Depressants may enhance the CNS depressant effect of Piribedil [INT]. Monitor therapy

Potassium Chloride: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Avoid combination

Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy

Pramlintide: May enhance the anticholinergic effect of Anticholinergic Agents. These effects are specific to the GI tract. Consider therapy modification

QuiNINE: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Ramosetron: Anticholinergic Agents may enhance the constipating effect of Ramosetron. Monitor therapy

RimabotulinumtoxinB: Anticholinergic Agents may enhance the anticholinergic effect of RimabotulinumtoxinB. Monitor therapy

ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy

Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy

Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy

Secretin: Anticholinergic Agents may diminish the therapeutic effect of Secretin. Management: Avoid using drugs with substantial anticholinergic effects in patients receiving secretin whenever possible. If such agents must be used in combination, monitor closely for a diminished response to secretin. Consider therapy modification

Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors. Specifically, the risk of psychomotor impairment may be enhanced. Monitor therapy

Sodium Oxybate: May enhance the CNS depressant effect of CNS Depressants. Management: Consider alternatives to combined use. When combined use is needed, consider minimizing doses of one or more drugs. Use of sodium oxybate with alcohol or sedative hypnotics is contraindicated. Consider therapy modification

Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Consider therapy modification

Tapentadol: May enhance the CNS depressant effect of CNS Depressants. Management: Start tapentadol at a dose of one-third to one-half of the normal dose if being initiated in a patient who is taking another drug with CNS depressant effects. Monitor closely for evidence of excessive CNS depression. Consider therapy modification

Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination

Thiazide and Thiazide-Like Diuretics: Anticholinergic Agents may increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Thioridazine: Chlorpheniramine may enhance the arrhythmogenic effect of Thioridazine. Thioridazine may increase the serum concentration of Chlorpheniramine. Management: Avoid this combination when possible. If used, monitor closely for arrhythmia as well as general toxicity of chlorpheniramine. Consider therapy modification

Tiotropium: Anticholinergic Agents may enhance the anticholinergic effect of Tiotropium. Avoid combination

Topiramate: Anticholinergic Agents may enhance the adverse/toxic effect of Topiramate. Monitor therapy

Trimeprazine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Umeclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Consider therapy modification

Test Interactions

May suppress the wheal and flare reactions to skin test antigens.

Adverse Reactions

Frequency not defined.

>10%:

Central nervous system: Drowsiness (slight to moderate)

Respiratory: Thickening of bronchial secretions

1% to 10%:

Central nervous system: Dizziness, excitability, fatigue, headache, nervousness

Endocrine & metabolic: Weight gain

Gastrointestinal: Abdominal pain, diarrhea, increased appetite, nausea, xerostomia

Genitourinary: Urinary retention

Neuromuscular & skeletal: Arthralgia, weakness

Ophthalmic: Diplopia

Renal: Polyuria

Respiratory: Pharyngitis

Warnings/Precautions

Concerns related to adverse effects:

• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

Disease-related concerns:

• Cardiovascular disease: Use with caution in patients with cardiovascular disease (including hypertension and ischemic heart disease).

• Increased intraocular pressure: Use with caution in patients with increased intraocular pressure.

• Prostatic hyperplasia/urinary obstruction: Use with caution in patients with prostatic hyperplasia and/or GU obstruction.

• Respiratory disease: Use with caution in patients with asthma or other chronic breathing disorders.

• Thyroid dysfunction: Use with caution in patients with thyroid dysfunction.

Concurrent drug therapy issues:

• Sedatives: Effects may be potentiated when used with other sedative drugs or ethanol.

Special populations:

• Pediatric: Antihistamines may cause excitation in young children. Not for OTC use in children <2 years of age.

Dosage form specific issues:

• Benzyl alcohol and derivatives: Some dosage forms may contain sodium benzoate/benzoic acid; benzoic acid (benzoate) is a metabolite of benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP ["Inactive" 1997]; CDC, 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors, 2001); avoid or use dosage forms containing benzyl alcohol derivative with caution in neonates. See manufacturer’s labeling.

Pregnancy Considerations

Maternal chlorpheniramine use has generally not resulted in an increased risk of birth defects (Aselton 1985; Gilboa 2009; Heinonen 1977; Jick 1981). Antihistamines may be used for the treatment of rhinitis, urticaria, and pruritus with rash in pregnant women (although second generation antihistamines may be preferred) (Angier 2010; Murase 2014; Wallace 2008; Zuberbier 2014). Antihistamines are not recommended for treatment of pruritus associated with intrahepatic cholestasis in pregnancy (Ambros-Rudolph 2011; Kremer 2011).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience fatigue or anxiety. Have patient report immediately to prescriber severe dizziness, passing out, severe loss of strength and energy, bruising, bleeding, chills, severe pharyngitis, difficult urination, tachycardia, arrhythmia, seizures, vision changes, change in balance, confusion, agitation, or tremors (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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