D%252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cold

# Dextromethorphan/Guaifenesin (D%252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cold) ## Overview Dextromethorphan is a cough suppressant. Guaifenesin is an expectorant that helps loosen mucus. This combination is formulated in various strengths. ## Primary Indications * Temporary relief of cough associated with the common cold. * Temporary relief of chest congestion and thinning of mucus associated with the common cold. ## Adult Dosing Dosing varies significantly based on specific product formulation (e.g., 10 mg/100 mg, 20 mg/200 mg, 30 mg/400 mg). Always refer to the specific product labeling. A common adult dosing regimen for products containing **dextromethorphan 10 mg / guaifenesin 100 mg per 5 mL** is: * **Dextromethorphan:** 10-20 mg orally every 4 hours as needed. Maximum 120 mg/day. * **Guaifenesin:** 100-200 mg orally every 4 hours as needed. Maximum 1200 mg/day. A common adult dosing regimen for products containing **dextromethorphan 20 mg / guaifenesin 200 mg per 10 mL** is: * **Dextromethorphan:** 20 mg orally every 4 hours as needed. Maximum 120 mg/day. * **Guaifenesin:** 200 mg orally every 4 hours as needed. Maximum 1200 mg/day. A common adult dosing regimen for products containing **dextromethorphan 30 mg / guaifenesin 400 mg per 10 mL or tablet** is: * **Dextromethorphan:** 30 mg orally every 6-12 hours as needed. Maximum 120 mg/day. * **Guaifenesin:** 400 mg orally every 4-12 hours as needed. Maximum 2400 mg/day. **Note:** Specific dosing and frequency will depend on the concentration of the product being used. Adhere strictly to the product label. ## Pediatric Dosing Dosing for children varies based on age and the specific product formulation. Always consult the product labeling. **General Pediatric Dosing Guidelines (Consult Specific Product for Age Cutoffs and Exact Doses):** * **Children 6 to <12 years:** Doses are typically half of the adult dose, administered every 4-6 hours as needed. Do not exceed adult maximum daily doses. * **Children <6 years:** Safety and efficacy are generally not established. Use should be at the discretion of a healthcare provider, with extreme caution. Some products may have specific age recommendations (e.g., >4 years). ## Dose Adjustments * **Hepatic Impairment:** Dextromethorphan is metabolized by CYP2D6. Patients with hepatic impairment may have reduced clearance. Caution and potentially reduced dosing may be warranted, though specific guidelines are often lacking for combination products. * **Renal Impairment:** No specific dose adjustments are typically recommended for mild to moderate renal impairment for either component. Severe renal impairment may warrant caution due to potential drug accumulation, but specific guidelines are often lacking. ## Contraindications * Hypersensitivity to dextromethorphan or guaifenesin. * Use within 14 days of MAOI therapy (for dextromethorphan). * Use in patients with respiratory depression (for dextromethorphan). * Use in patients with chronic cough, persistent cough, or cough accompanied by excessive secretions (relative contraindication for dextromethorphan unless otherwise directed by a physician). * Some formulations may have additional contraindications based on excipients. ## Adverse Effects * **Dextromethorphan:** Dizziness, drowsiness, nausea, vomiting, confusion, hallucinations (especially at higher doses). Serotonin syndrome is a risk with concomitant serotonergic agents. Respiratory depression with overdose. * **Guaifenesin:** Nausea, vomiting, dizziness, headache, rash. ## Key Drug Interactions * **Monoamine Oxidase Inhibitors (MAOIs):** Concomitant use with dextromethorphan can lead to a potentially fatal serotonin syndrome (symptoms include agitation, confusion, rapid heart rate, high blood pressure, muscle rigidity, seizures). Avoid use within 14 days of MAOI therapy. * **Serotonergic Agents:** Antidepressants (SSRIs, SNRIs, TCAs), triptans, St. John's Wort, tramadol, etc. Increased risk of serotonin syndrome when used with dextromethorphan. * **CYP2D6 Inhibitors:** Fluoxetine, paroxetine, quinidine, ritonavir can increase dextromethorphan levels, potentially leading to increased adverse effects. * **Alcohol:** May potentiate CNS depressant effects of dextromethorphan. ## Monitoring * Monitor for effectiveness in cough suppression and mucus expectoration. * Monitor for adverse effects, particularly CNS effects (drowsiness, dizziness, confusion) and signs of serotonin syndrome. * Ensure adequate hydration is maintained to support guaifenesin's effectiveness. ## Clinical Pearls * This combination is for symptomatic relief and does not treat the underlying cause of the cough or congestion. * Guaifenesin is most effective when the patient is well-hydrated. Encourage fluid intake. * Be aware of the risk of serotonin syndrome, especially in patients taking other serotonergic medications. * Many over-the-counter cold and flu products contain dextromethorphan or guaifenesin; review all medications to avoid duplication and potential overdose. * Dextromethorphan abuse is a concern; patients may attempt to use higher-than-recommended doses for dissociative effects. *** **Disclaimer:** This information is intended for healthcare professionals. Always consult the most current prescribing information and relevant guidelines for complete details before making any clinical decisions. Product formulations and recommendations can vary.