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Dextromethorphan and Menthol

Generic name: dextromethorphan/menthol systemic

Brand names: Delsym Cough+ Soothing Action, Robitussin Medi-Soothers Cough DM

Dosage Forms

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

Lozenge, Mouth/Throat:

Delsym Cough Relief: Dextromethorphan hydrobromide 5 mg and menthol 5 mg (16 ea [DSC]) [contains fd&c yellow #10 (quinoline yellow), fd&c yellow #6 (sunset yellow); honey-lemon flavor]

Delsym Cough Relief: Dextromethorphan hydrobromide 5 mg and menthol 5 mg (16 ea [DSC]) [sugar free; contains fd&c red #40; cherry flavor]

Delsym Cough+ Soothing Action: Dextromethorphan hydrobromide 5 mg and menthol 5 mg (16 ea [DSC]) [contains fd&c yellow #10 (quinoline yellow), fd&c yellow #6 (sunset yellow); honey-lemon flavor]

Delsym Cough+ Soothing Action: Dextromethorphan hydrobromide 5 mg and menthol 5 mg (16 ea [DSC]) [sugar free; contains fd&c red #40; cherry flavor]

Robitussin Medi-Soothers: Dextromethorphan hydrobromide 5 mg and menthol 5 mg (4 ea [DSC], 16 ea [DSC])

Pharmacology

Mechanism of Action

Dextromethorphan: 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

Menthol: Local anesthetic and counterirritant to relieve minor sore throat irritation

Use: Labeled Indications

Cough suppressant/sore throat: Temporary relief of sore throat, sore mouth, minor throat irritation, and cough due to minor throat and bronchial irritation as may occur with the common cold.

Contraindications

OTC labeling: When used for self-medication, do not use if you are taking a MAO inhibitor or within 2 weeks after stopping a MAO inhibitor; do not use in children <6 years of age

Dosage and Administration

Dosing: Adult

Cough suppressant/sore throat: Oral: A total of 2 lozenges (dextromethorphan 5 mg/menthol 5 mg per lozenge) dissolved in mouth, 1 immediately after the other. May repeat every 4 hours; maximum: 12 lozenges (dextromethorphan 60 mg/menthol 60 mg) daily

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Cough suppressant/sore throat: Oral:

Children <6 years: Not for OTC use.

Children 6 to <12 years: One lozenge (dextromethorphan 5 mg/menthol 5 mg per lozenge) dissolved in mouth. May repeat every 4 hours; maximum: 6 lozenges (dextromethorphan 30 mg/menthol 30 mg) daily

Children ≥12 years and Adolescents: Refer to adult dosing.

Administration

Allow lozenge to dissolve slowly in the mouth.

Storage

Store between 20°C to 25°C (68°F to 77°F).

Drug Interactions

Abiraterone Acetate: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). 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

Ajmaline: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Asunaprevir: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Consider therapy modification

CloBAZam: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Cobicistat: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

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

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

Dacomitinib: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Management: Avoid concurrent use of dacomitinib with CYP2D6 subtrates that have a narrow therapeutic index. Consider therapy modification

Darunavir: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Imatinib: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Lumefantrine: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Memantine: NMDA Receptor Antagonists may enhance the adverse/toxic effect of Memantine. Monitor therapy

Monoamine Oxidase Inhibitors: May enhance the serotonergic effect of Dextromethorphan. This may cause serotonin syndrome. Avoid combination

Panobinostat: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Parecoxib: May increase the serum concentration of Dextromethorphan. Monitor therapy

Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Peginterferon Alfa-2b may increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Perhexiline: CYP2D6 Substrates (High risk with Inhibitors) may increase the serum concentration of Perhexiline. Perhexiline may increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). 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. Consider therapy modification

QuiNINE: May increase the serum concentration of CYP2D6 Substrates (High risk with Inhibitors). Monitor therapy

Selective Serotonin Reuptake Inhibitors (Strong CYP2D6 Inhibitors): Dextromethorphan may enhance the serotonergic effect of Selective Serotonin Reuptake Inhibitors (Strong CYP2D6 Inhibitors). This could result in serotonin syndrome. Selective Serotonin Reuptake Inhibitors (Strong CYP2D6 Inhibitors) may increase the serum concentration of Dextromethorphan. Management: Consider alternatives to this drug combination. If combined, monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes). Consider therapy modification

Serotonergic Agents (High Risk): Dextromethorphan may enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Exceptions: FLUoxetine; Isocarboxazid; Linezolid; Methylene Blue; Moclobemide; PARoxetine; Phenelzine; Tranylcypromine. Monitor therapy

Tipranavir: May increase the serum concentration of Dextromethorphan. Management: Consider avoiding dextromethorphan in patients taking tipranavir. If combined, monitor closely for increased dextromethorphan effects/toxicities. Consider therapy modification

Adverse Reactions

See Dextromethorphan monograph.

Warnings/Precautions

Concurrent drug therapy issues:

  • Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Other warnings/precautions:

  • Self-medication (OTC use): When used for self-medication (OTC) contact health care provider prior to use if you have a persistent or chronic cough associated with asthma, emphysema or smoking, or if you have cough with excess phlegm; notify healthcare provider if symptoms do not improve within 7 days, irritation, pain or redness persist/worsen, swelling develops, or cough is accompanied by fever, rash or persistent headache.

Special populations:

  • CYP2D6 poor metabolizers: Dextromethorphan is metabolized by hepatic CYP2D6. Poor metabolizers of CYP2D6 may have exaggerated or prolonged effects of dextromethorphan. Increased risk may be seen with concomitant use of potent CYP2D6 inhibitors; use with caution (Abduljalil 2010; Jurica 2012; Sager 2014; Zhou 2009).

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?)
  • 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 health care 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.

Source: Wolters Kluwer Health. Last updated October 18, 2019.