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Promethazine and Dextromethorphan

Pronunciation

(proe METH a zeen & deks troe meth OR fan)

Index Terms

  • Dextromethorphan and Promethazine

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Syrup: Promethazine hydrochloride 6.25 mg and dextromethorphan hydrobromide 15 mg per 5 mL (120 mL, 480 mL)

Pharmacologic Category

  • Antitussive
  • Histamine H1 Antagonist
  • Histamine H1 Antagonist, First Generation
  • Phenothiazine Derivative

Use: Labeled Indications

Temporary relief of coughs and upper respiratory symptoms associated with allergy or the common cold

Contraindications

Hypersensitivity to promethazine, dextromethorphan, or any component of the formulation (cross-reactivity between phenothiazines may occur); treatment of lower respiratory tract symptoms, including asthma

Dosing: Adult

Cough and upper respiratory symptoms: Oral: 5 mL every 4 to 6 hours; maximum: 30 mL in 24 hours

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Cough and upper respiratory symptoms: Oral: Children:

2 to <6 years: 1.25 to 2.5 mL every 4 to 6 hours; maximum: 10 mL in 24 hours

6 to <12 years: 2.5 to 5 mL every 4 to 6 hours; maximum: 20 mL in 24 hours

≥12 years and Adolescents: Refer to adult dosing

Dosing: Renal Impairment

There are no dosage adjustments provided in the manufacturer’s labeling.

Dosing: Hepatic Impairment

Adults: There are no dosage adjustments provided in the manufacturer’s labeling; use with caution (cholestatic jaundice has been reported with use).

Children ≥2 years and Adolescents: The manufacturer recommends to avoid use in pediatric patients with signs and symptoms of hepatic disease (extrapyramidal symptoms caused by promethazine may be confused with CNS signs of hepatic disease).

Dietary Considerations

Increase dietary intake of riboflavin.

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

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

Analgesics (Opioid): May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

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

Antiemetics (5HT3 Antagonists): May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Antipsychotic Agents: Serotonin Modulators may enhance the adverse/toxic effect of Antipsychotic Agents. Specifically, serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotic Agents may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. 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

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

CYP2B6 Inducers (Moderate): May decrease the serum concentration of CYP2B6 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

Dabrafenib: May decrease the serum concentration of CYP2B6 Substrates. Monitor therapy

Dapoxetine: May enhance the adverse/toxic effect of Serotonin Modulators. Avoid combination

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

EPINEPHrine (Nasal): Promethazine may diminish the vasoconstricting effect of EPINEPHrine (Nasal). Monitor therapy

EPINEPHrine (Oral Inhalation): Promethazine may diminish the therapeutic effect of EPINEPHrine (Oral Inhalation). Monitor therapy

Epinephrine (Racemic): Promethazine may diminish the vasoconstricting effect of Epinephrine (Racemic). Management: Monitor for diminished vasoconstrictive effects of racemic epinephrine (e.g., diminished efficacy when used for gingival retraction). This interaction is likely of less concern in patients receiving epinephrine for other purposes (e.g., bronchodilation). Monitor therapy

EPINEPHrine (Systemic): Promethazine may diminish the vasoconstricting effect of EPINEPHrine (Systemic). Management: When vasoconstrictive effects are desired in patients receiving promethazine, consider alternatives to epinephrine. Consider use of norepinephrine or phenylephrine, and avoid epinephrine, when treating hypotension associated with promethazine overdose. Consider therapy modification

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

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

Highest Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Highest Risk QTc-Prolonging Agents. Management: Avoid such combinations when possible. Use should be accompanied by close monitoring for evidence of QT prolongation or other alterations of cardiac rhythm. 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

Lumacaftor: May decrease the serum concentration of CYP2B6 Substrates. Monitor therapy

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

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

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

Metaxalone: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. 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

Methylene Blue: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Avoid combination

Metoclopramide: May enhance the adverse/toxic effect of Promethazine. Avoid combination

MetyroSINE: May enhance the adverse/toxic effect of Promethazine. Monitor therapy

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

MiFEPRIStone: May enhance the QTc-prolonging effect of QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying). Management: Though the drugs listed here have uncertain QT-prolonging effects, they all have some possible association with QT prolongation and should generally be avoided when possible. Consider therapy modification

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

Moderate Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Moderate Risk QTc-Prolonging Agents. 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

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

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

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

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: 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. 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

Serotonin Modulators: May enhance the adverse/toxic effect of other Serotonin Modulators. The development of serotonin syndrome may occur. Exceptions: Nicergoline; Tedizolid. 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

Thiotepa: May increase the serum concentration of CYP2B6 Substrates. Monitor therapy

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

TraMADol: Serotonin Modulators may enhance the adverse/toxic effect of TraMADol. The risk of seizures may be increased. TraMADol may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. 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

See individual agents.

ALERT: U.S. Boxed Warning

Pediatrics:

Do not use in patients younger than 2 years of age because of potential for fatal respiratory depression. Administer with caution to children older than 2 years of age.

Warnings/Precautions

Concerns related to adverse effects:

• Altered cardiac conduction: May alter cardiac conduction (life-threatening arrhythmias have occurred with therapeutic doses of phenothiazines).

• Anticholinergic effects: Phenothiazines may cause anticholinergic effects (constipation, xerostomia, blurred vision, urinary retention); therefore, they should be used with caution in patients with decreased gastrointestinal motility, urinary retention, BPH, xerostomia, or visual problems.

• Extrapyramidal symptoms: May cause extrapyramidal symptoms, including pseudoparkinsonism, acute dystonic reactions, akathisia, and tardive dyskinesia.

• Neuroleptic malignant syndrome (NMS): Use may be associated with NMS; monitor for mental status changes, fever, muscle rigidity and/or autonomic instability.

• Orthostatic hypotension: May cause orthostatic hypotension; use with caution in patients at risk of this effect or in those who would not tolerate transient hypotensive episodes (cerebrovascular disease, cardiovascular disease, hypovolemia, or concurrent medication use which may predispose to hypotension/bradycardia).

• Sedation: May be sedating, use with caution in disorders where CNS depression is a feature; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

• Temperature regulation: Impaired core body temperature regulation may occur; caution with strenuous exercise, heat exposure, dehydration, and concomitant medication possessing anticholinergic effects.

Disease-related concerns:

• Bone marrow suppression: Use with caution in patients with bone marrow suppression; leukopenia and agranulocytosis have been reported.

• Cardiovascular disease: Use with caution in patients with severe cardiovascular disease.

• Glaucoma: Use with caution in patients with narrow-angle glaucoma; condition may be exacerbated by cholinergic blockade. Screening is recommended.

• Hepatic impairment: Use with caution in patients with hepatic impairment; cholestatic jaundice has been reported with promethazine use. Avoid use in pediatric patients with signs and symptoms of hepatic disease (extrapyramidal symptoms caused by promethazine may be confused with CNS signs of hepatic disease).

• Myasthenia gravis: Use with caution in patients with myasthenia gravis; condition may be exacerbated by cholinergic blockade.

• Parkinson disease: Use with caution in patients with Parkinson disease; may have increased risk of tardive dyskinesia.

• Respiratory disease: Use with caution in patients with severe respiratory disease (asthma, COPD, sleep apnea); may lead to potentially fatal respiratory depression.

• Seizures: Use with caution in patients at risk of seizures, including those with a history of seizures, head trauma, brain damage, alcoholism, or concurrent therapy with medications which may lower seizure threshold.

Concurrent drug therapy issues:

• Antiemetic effects: May mask toxicity of other drugs or conditions (eg, intestinal obstruction, Reye's syndrome, brain tumor) due to antiemetic effects.

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

Special populations:

• Pediatric: [U.S. Boxed Warning]: Safety and efficacy of this combination have not been established in children <2 years of age (use of promethazine is contraindicated). In children ≥2 years, use the lowest possible dose; other drugs with respiratory depressant effects should be avoided. Avoid use in children who may have Reye syndrome or hepatic disease as adverse reactions caused by promethazine may be confused with signs of primary disease.

Pregnancy Risk Factor

C

Pregnancy Considerations

Reproduction studies have not been conducted with this combination. Refer to individual monographs.

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, dry mouth, vomiting, or nausea. Have patient report immediately to prescriber signs of infection, bradycardia, difficulty breathing, slow breathing, shallow breathing, noisy breathing, severe dizziness, passing out, severe constipation, urinary retention, loss of strength and energy, abnormal movements, twitching, change in balance, dysphagia, difficulty speaking, hallucinations, mood changes, tinnitus, seizures, bruising, bleeding, vision changes, severe anxiety, insomnia, jaundice, or signs of neuroleptic malignant syndrome (fever, muscle cramps or stiffness, dizziness, very bad headache, confusion, change in thinking, fast heartbeat, abnormal heartbeat, or sweating a lot) (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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