What is the recommended dosing for Geritussin (dextromethorphan)?

Geritussin (Dextromethorphan) Dosing

The provided evidence does not contain specific dosing information for "Geritussin" as a branded product, but standard dextromethorphan dosing for cough suppression is well-established, with therapeutic efficacy requiring higher doses than typically found in over-the-counter preparations.

Standard Dextromethorphan Dosing

FDA-Approved Dosing (Extended-Release Formulation)

• Adults and children ≥12 years: 10 mL every 12 hours, not to exceed 20 mL in 24 hours 1
• Children 6 to <12 years: 5 mL every 12 hours, not to exceed 10 mL in 24 hours 1
• Children 4 to <6 years: 2.5 mL every 12 hours, not to exceed 5 mL in 24 hours 1
• Children <4 years: Do not use 1

Evidence-Based Therapeutic Dosing

For optimal cough suppression, standard over-the-counter doses are often subtherapeutic. 2, 3

• Maximum cough reflex suppression occurs at 60 mg and provides prolonged relief 2, 3, 4
• Standard OTC dosing (15-30 mg) frequently fails to provide adequate symptom control 2, 4
• A dose-response relationship exists, with medium to high doses (0.45-0.94 mg/kg) showing better symptomatic relief than low doses 5

Clinical Application Algorithm

For Acute Viral Cough (First-Line Approach)

1. Start with non-pharmacological measures: Honey and lemon mixtures are as effective as pharmacological treatments for benign viral cough 2, 4
2. If pharmacological treatment needed: Dextromethorphan 30-60 mg provides optimal cough suppression 2, 3
3. For nocturnal cough specifically: Consider first-generation sedating antihistamines 2, 4

For Postinfectious Cough

• First try: Inhaled ipratropium before central antitussives 2
• If ipratropium fails: Consider dextromethorphan as a central acting antitussive 6, 2
• For severe paroxysms: Short-course prednisone 30-40 mg daily may be indicated 6, 2

Critical Safety Considerations

Combination Product Warning

Exercise extreme caution with higher doses of dextromethorphan in combination products containing acetaminophen or other ingredients to avoid inadvertent overdose of these components 2, 3, 4

Abuse Potential

• Doses exceeding 1500 mg/day can induce PCP-like psychosis with delusions, hallucinations, and paranoia 7
• DXM is not detected on standard urine drug screens, making abuse under-recognized 7

Duration of Use

• Reassess if cough persists beyond 14 days to evaluate for alternative diagnoses 2
• Cough lasting >3 weeks requires full diagnostic workup rather than continued antitussive therapy 6, 2

Comparison with Codeine

Dextromethorphan is preferred over codeine due to superior safety profile 2

• Codeine has no greater efficacy than dextromethorphan 2, 4
• Codeine carries significantly more adverse effects including drowsiness, nausea, constipation, and physical dependence 2, 4

Common Pitfalls to Avoid

• Do not prescribe subtherapeutic OTC doses (15-30 mg) expecting adequate relief 2, 4
• Do not use for productive cough where secretion clearance is beneficial 2
• Do not continue indefinitely without reassessing the underlying cause 2
• Do not overlook combination product ingredients when prescribing higher therapeutic doses 2, 3, 4