Antitussives: Medications for Cough Suppression
Antitussives are pharmacologic agents designed to suppress cough by inhibiting the cough reflex, used primarily for short-term symptomatic relief when coughing is excessive or interferes with daily activities or sleep. 1
Types of Antitussives
Centrally Acting Antitussives
Opioid antitussives work by acting on the cough center in the brain stem to suppress the cough reflex 1:
- Codeine - FDA-approved for temporary relief of cough due to minor throat and bronchial irritation, also helps loosen phlegm and thin bronchial secretions 2
- Hydrocodone - An opioid analgesic with antitussive properties 3
- Dextromethorphan - A non-sedating opioid derivative that temporarily relieves cough due to minor throat and bronchial irritation, helping patients get to sleep 4, 1
- Pholcodeine - Similar to codeine but with fewer side effects 1, 5
First-generation antihistamines with sedative properties can suppress cough, particularly useful for nocturnal cough 1, 6
Peripherally Acting Antitussives
- Menthol - Suppresses the cough reflex through inhalation, providing acute but short-lived relief 1
- Ipratropium bromide (inhaled) - Can suppress subjective measures of cough in patients with upper respiratory infections or chronic bronchitis 1
Clinical Applications
Acute viral cough - Generally self-limiting and may not require prescription treatment 1:
Chronic cough - Antitussives may be indicated when 1, 5:
- The etiology of cough is unknown (precluding specific therapy)
- Specific therapy requires time to become effective
- Specific therapy will be ineffective (e.g., inoperable lung cancer)
Efficacy and Dosing Considerations
Dextromethorphan shows dose-dependent efficacy with maximum cough reflex suppression at 60mg, though over-the-counter preparations often contain subtherapeutic doses 1
Opioid antitussives like codeine and morphine may require higher doses for effectiveness, which can be associated with significant side effects 5, 8
Efficacy varies by condition - Peripheral and central antitussives can be useful in chronic bronchitis but may have limited efficacy in cough due to upper respiratory infections 1, 9
Side Effects and Precautions
Opioid antitussives can cause drowsiness, nausea, constipation, and physical dependence 8, 10
Sedative antihistamines cause drowsiness, which may be beneficial for nighttime cough but problematic during daytime use 1, 6
Codeine requires bioactivation by CYP2D6 into morphine in the liver, with efficacy related to plasma morphine concentrations - caution is needed particularly in children 10
Clinical Decision Making
For acute cough: Start with non-pharmacological approaches or simple over-the-counter preparations containing dextromethorphan or menthol 1
For persistent cough: Identify and treat the underlying cause when possible before resorting to symptomatic antitussive therapy 1, 9
For nighttime cough: Consider sedating antihistamines or dextromethorphan to improve sleep 1, 4
For severe chronic cough: Reserve higher-potency opioids like morphine for the most severe cases or patients with terminal conditions who may also benefit from analgesic effects 5
Important Considerations
Antitussives provide symptomatic relief but do not treat the underlying cause of cough 1, 7
Suppressant therapy is most effective when used for short-term reduction of coughing 1
Voluntary suppression of cough may be sufficient in some cases to reduce cough frequency 1
The American College of Chest Physicians notes that relatively few drugs are consistently effective as cough suppressants 1