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Pronunciation
(deks troe meth OR fan)
Generic Available (U.S.)
Yes: Excludes strip
Brand Names: U.S.
Pharmacologic Category
Pharmacologic Category Synonyms
Use: Labeled Indications
Symptomatic relief of coughs caused by the common cold or inhaled irritants
Use: Unlabeled
N-methyl-D-aspartate (NMDA) antagonist
Pregnancy Considerations
Maternal use of standard OTC doses of dextromethorphan when used as an antitussive during the first trimester of pregnancy has not been found to increase the risk of teratogenic effects. Dextromethorphan is metabolized in the liver via CYP2D6 and CYP3A enzymes. The activity of both enzymes is increased in the mother during pregnancy. In the fetus, CYP2D6 activity is low in the fetal liver and CYP3A4 activity is present by ~17 weeks gestation.
Contraindications
Concurrent administration with or within 2 weeks of discontinuing an MAO inhibitor
Warnings/Precautions
Concurrent drug therapy issues:
• Serotonin syndrome: Symptoms of agitation, confusion, hallucinations, hyper-reflexia, myoclonus, shivering, and tachycardia may occur with concomitant proserotonergic drugs (ie, SSRIs/SNRIs or triptans); especially with higher dextromethorphan doses.
Special populations:
• Debilitated patients: Use with caution in patients who are sedated, debilitated or confined to a supine position.
• Neonates: Some products may contain sodium benzoate which has been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; in vitro and animal studies have shown that benzoate, a metabolite of benzyl alcohol, displaces bilirubin from protein binding sites; avoid use of products containing sodium benzoate in neonates.
• Pediatrics: Use with caution in atopic children. Not for OTC use in children <4 years of age.
Dosage form specific issues:
• Sodium benzoate: Some products may contain sodium benzoate may cause allergic reactions in susceptible individuals.
• Tartrazine: Some products may contain tartrazine.
Other warnings/precautions:
• Abuse/misuse: Healthcare providers should be alert to problems of abuse or misuse. Abuse can cause death, brain damage, seizure, loss of consciousness, and irregular heartbeat.
• Self-medication (OTC use): When used for self medication (OTC) notify healthcare provider if symptoms do not improve within 7 days, or are accompanied by fever, rash or persistent headache. Do not use for persistent or chronic cough (as with smoking, asthma, chronic bronchitis, emphysema) or if cough is accompanied by excessive phlegm unless directed to do so by healthcare provider.
Adverse Reactions
Frequency not defined.
Central nervous system: Confusion, excitement, irritability, nervousness, serotonin syndrome
Metabolism/Transport Effects
Substrate of CYP2B6 (minor), CYP2C19 (minor), CYP2C9 (minor), CYP2D6 (major), CYP2E1 (minor), CYP3A4 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Inhibits CYP2D6 (weak)
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. Risk D: Consider therapy modification
Antipsychotics: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Risk C: Monitor therapy
Conivaptan: May increase the serum concentration of CYP3A4 Substrates (Low risk). Risk C: Monitor therapy
CYP2D6 Inhibitors (Moderate): May decrease the metabolism of CYP2D6 Substrates. Risk C: Monitor therapy
CYP2D6 Inhibitors (Strong): May decrease the metabolism of CYP2D6 Substrates. Risk D: Consider therapy modification
Cyproterone: May decrease the serum concentration of CYP2E1 Substrates. Risk C: Monitor therapy
Darunavir: May increase the serum concentration of CYP2D6 Substrates. Risk C: Monitor therapy
MAO Inhibitors: May enhance the serotonergic effect of Dextromethorphan. This may cause serotonin syndrome. Risk X: Avoid combination
Metoclopramide: Serotonin Modulators may enhance the adverse/toxic effect of Metoclopramide. This may be manifest as symptoms consistent with serotonin syndrome or neuroleptic malignant syndrome. Risk C: Monitor therapy
Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates. Risk C: Monitor therapy
QuiNIDine: May increase the serum concentration of Dextromethorphan. Management: Avoid concurrent use of these agents when possible, unless the increased psychoactive effects of dextromethorphan are desired. Since codeine activation is also inhibited by quinidine, codeine is unlikely to be suitable as an alternative antitussive. Risk D: Consider therapy modification
Selective Serotonin Reuptake Inhibitors: May enhance the serotonergic effect of Dextromethorphan. Selective Serotonin Reuptake Inhibitors may increase the serum concentration of Dextromethorphan. Management: Avoid the concurrent use of dextromethorphan and SSRIs, particularly fluoxetine and paroxetine, when possible. The risk for this interaction may persist for several weeks following discontinuation of fluoxetine or paroxetine. Exceptions: FluvoxaMINE. Risk D: Consider therapy modification
Serotonin Modulators: May enhance the adverse/toxic effect of other Serotonin Modulators. The development of serotonin syndrome may occur. Risk D: Consider therapy modification
Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates. Risk C: Monitor therapy
Mechanism of Action
Decreases the sensitivity of cough receptors and interrupts cough impulse transmission by depressing the medullary cough center through sigma receptor stimulation; structurally related to codeine
Pharmacodynamics/Kinetics
Onset of action: Antitussive: 15-30 minutes
Duration: ≤6 hours
Metabolism: Hepatic via demethylation via CYP2D6 to dextrorphan (active); CYP3A4 and CYP3A5 form smaller amounts of 3-hydroxy and 3-methoxy derivatives
Half-life elimination: Dextromethorphan: Extensive metabolizers: 2-4 hours; poor metabolizers: 24 hours
Time to peak: 2-3 hours
Excretion: Primarily in urine as metabolites
Dosage
Oral:
Children:
<4 years: Not for OTC use
4-6 years (syrup): 2.5-7.5 mg every 4-8 hours; extended release is 15 mg twice daily (maximum: 30 mg/24 hours)
6-12 years: 5-10 mg every 4 hours or 15 mg every 6-8 hours; extended release is 30 mg twice daily (maximum: 60 mg/24 hours)
Children >12 years and Adults: 10-20 mg every 4 hours or 30 mg every 6-8 hours; extended release: 60 mg twice daily; maximum: 120 mg/day
Test Interactions
False-positive phencyclidine (PCP), opiates, opioids and heroin urine drug screen
Dietary Considerations
Some products may contain sodium.
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Effects on Mental Status
May cause drowsiness or depression
Mental Health: Effects on Psychiatric Treatment
Use with MAO inhibitors may cause hypertensive crisis; avoid combination
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Capsule, extended release, oral, as sulfate: 10 mg
Capsule, liquid filled, oral, as hydrobromide:
Robafen Cough: 15 mg
Robitussin® CoughGels™ Long-Acting: 15 mg [DSC]
Robitussin® Lingering Cold Long-Acting CoughGels®: 15 mg [contains coconut oil]
Liquid, oral, as hydrobromide: 15 mg/5 mL (120 mL)
Creo-Terpin®: 10 mg/15 mL (120 mL) [contains ethanol 25%, tartrazine]
Scot-Tussin® Diabetes: 10 mg/5 mL (118 mL) [ethanol free, gluten free, sugar free; contains propylene glycol; cherry-strawberry flavor]
Vicks® 44® Cough Relief: 10 mg/5 mL (120 mL) [contains ethanol, propylene glycol, sodium 28 mg/15 mL, sodium benzoate]
Vicks® Nature Fusion™ Cough: 30 mg/30 mL (240 mL) [dye free, ethanol free, gluten free; contains sodium 36 mg/30 mL; honey flavor]
Lozenge, oral, as hydrobromide:
Hold® DM: 5 mg (10s) [cherry flavor]
Hold® DM: 5 mg (10s) [original flavor]
Trocal®: 7.5 mg (50s [DSC], 300s [DSC]) [cherry flavor]
Solution, oral, as hydrobromide:
PediaCare® Children's Long-Acting Cough: 7.5 mg/5 mL (118 mL) [ethanol free; contains sodium 15 mg/5 mL, sodium benzoate; grape flavor]
Vicks® DayQuil® Cough: 15 mg/15 mL (177 mL, 295 mL) [ethanol free; contains propylene glycol, sodium 15 mg/15 mL; citrus flavor]
Strip, orally disintegrating, oral, as hydrobromide:
Triaminic Thin Strips® Children's Long Acting Cough: 7.5 mg (14s, 16s) [contains ethanol; cherry flavor; equivalent to dextromethorphan 5.5 mg]
Suspension, extended release, oral:
Delsym®: Dextromethorphan polistirex [equivalent to dextromethorphan hydrobromide] 30 mg/5 mL (89 mL, 148 mL) [ethanol free; contains propylene glycol, sodium 7 mg/5 mL; grape flavor]
Delsym®: Dextromethorphan polistirex [equivalent to dextromethorphan hydrobromide] 30 mg/5 mL (89 mL, 148 mL) [ethanol free; contains propylene glycol, sodium 7 mg/5 mL; orange flavor]
Syrup, oral, as hydrobromide:
Creomulsion® Adult Formula: 20 mg/15 mL (120 mL) [ethanol free; contains sodium benzoate]
Creomulsion® for Children: 5 mg/5 mL (120 mL) [ethanol free; contains sodium benzoate; cherry flavor]
Father John's®: 10 mg/5 mL (118 mL, 236 mL) [ethanol free]
Robitussin® Children's Cough Long-Acting: 7.5 mg/5 mL (118 mL) [ethanol free; contains propylene glycol, sodium 5 mg/5 mL, sodium benzoate; fruit-punch flavor]
Robitussin® Cough Long Acting: 15 mg/5 mL (240 mL [DSC]) [contains ethanol, sodium benzoate]
Robitussin® Lingering Cold Long-Acting Cough: 15 mg/5 mL (118 mL) [contains ethanol 1.4%, menthol, sodium benzoate]
Silphen-DM: 10 mg/5 mL (120 mL) [strawberry flavor]
Triaminic® Children's Cough Long Acting: 7.5 mg/5 mL (118 mL) [contains benzoic acid, propylene glycol, sodium 7 mg/5 mL]
Tablet, oral, as hydrobromide:
Nycoff: 15 mg
References
Moeller KE, Lee KC, and Kissack JC, “Urine Drug Screening: Practical Guide for Clinicians,” Mayo Clin Proc, 2008, 83(1):66-76.
Schier J, “Avoid Unfavorable Consequences: Dextromethorphan Can Bring About a False-Positive Phencyclidine Urine Drug Screen,” J Emerg Med, 2000, 18(3):379-81.
Schwartz AR, Pizon AF, and Brooks DE, “Dextromethorphan-Induced Serotonin Syndrome,” Clin Toxicol (Phila), 2008, 46(8):771-3.
Siu A and Drachtman R, “Dextromethorphan: A Review of N-methyl-D-aspartate Receptor Antagonist in the Management of Pain,” CNS Drug Rev, 2007, 13(1):96-106.
International Brand Names
Lexi-Comp.com
Last full review/revision February 2012
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