What liquid prescription-strength medications can be given to a patient with a cough, considering their medical history and demographics?

Liquid Prescription-Strength Cough Medications

For prescription-strength liquid cough treatment, dextromethorphan extended-release oral suspension (e.g., Delsym) at 60 mg is the recommended first-line pharmacological option, offering superior efficacy and safety compared to codeine-based alternatives. 1, 2

Preferred Liquid Formulation

Dextromethorphan Polistirex Extended-Release Oral Suspension is available as a prescription-strength liquid formulation that provides 12-hour cough relief. 3

• The optimal dose for maximum cough suppression is 60 mg, which demonstrates a clear dose-response relationship 1, 2
• Standard over-the-counter dosing (30 mg or less) is often subtherapeutic and may not provide adequate relief 1, 2
• This formulation is alcohol-free and comes with a dosing cup 3
• Important caveat: Some preparations contain sodium metabisulfite, which may cause allergic reactions in susceptible individuals 3

Alternative Liquid Options Based on Clinical Scenario

For Productive Cough (When Secretion Clearance is Needed)

Guaifenesin liquid (expectorant) should be prescribed when the goal is to increase cough clearance rather than suppress it. 4

• Available in sugar-free and alcohol-free formulations 4
• Appropriate for bronchitis or conditions where mucus clearance is beneficial 5

For Nocturnal Cough Disrupting Sleep

First-generation antihistamines with sedative properties (e.g., diphenhydramine liquid) can be prescribed when cough primarily disrupts sleep. 1, 2

• The sedative effect is therapeutically valuable for nighttime cough 1, 6
• Particularly useful when cough interferes with patient's daily activities and rest 6

For Postinfectious Cough

Inhaled ipratropium bromide should be tried first before central antitussives for postinfectious cough persisting after acute respiratory infection. 1, 5

• This is the only inhaled anticholinergic recommended for cough suppression in upper respiratory infections 5
• If ipratropium fails and cough severely impacts quality of life, then consider dextromethorphan 1

Critical Dosing Considerations

Dextromethorphan dosing regimen:

• Standard dosing: 10-15 mg three to four times daily 2
• Maximum daily dose: 120 mg 2
• For severe cough requiring maximum suppression: single 60 mg dose 1, 2
• Pitfall to avoid: Check combination products carefully to prevent excessive acetaminophen or other ingredients when prescribing higher doses 2

Medications NOT Recommended

Codeine-containing liquid preparations should be avoided despite their historical use. 1, 2, 5

• Codeine has no greater efficacy than dextromethorphan 1, 7
• Codeine carries significantly more adverse effects including drowsiness, nausea, constipation, and physical dependence 1, 5
• Limited efficacy for acute cough due to upper respiratory infections 5

Promethazine has no established efficacy for cough suppression and should not be prescribed for this indication. 2

Red Flags Requiring Immediate Evaluation (Not Antitussive Treatment)

Do not prescribe cough suppressants if the patient presents with:

• Tachycardia, tachypnea, fever, or abnormal chest examination findings suggesting pneumonia 1
• Hemoptysis or breathlessness 1
• Cough with purulent sputum and malaise indicating serious lung infection 1
• Suspected foreign body inhalation 1

Special Population Considerations

Chronic Kidney Disease patients: No dose adjustment of dextromethorphan is required, as it is primarily metabolized hepatically by CYP2D6, not renally excreted. 2

Duration of Treatment

• Dextromethorphan should be used for short-term symptomatic relief only 2
• If cough persists beyond 3 weeks, discontinue antitussive therapy and perform full diagnostic workup for alternative diagnoses 2
• For postinfectious cough persisting beyond 8 weeks, consider diagnoses other than postinfectious cough 1