From the Guidelines
Codeine alone is generally more effective than codeine combined with caffeine for treating cough. For adults with persistent cough, codeine phosphate at doses of 30-60 mg every 4-6 hours can provide relief by suppressing the cough reflex in the central nervous system, as suggested by the study 1. Caffeine, when combined with codeine, doesn't enhance the antitussive effect and may actually counteract some of codeine's sedative properties, which can be beneficial for nighttime cough relief. However, it's essential to note that codeine carries risks of dependence, respiratory depression, and constipation, and should be used for the shortest duration possible, typically no more than 7 days. Non-opioid alternatives like dextromethorphan should be considered first, especially for children or those with respiratory conditions. The use of codeine is supported by the guidelines 1, which suggest an initial trial with demulcents or simple linctus, followed by pharmacological management using an opiate-derivative titrated to an acceptable side-effect profile.
Some key points to consider when using codeine for cough treatment include:
- The recommended dose of codeine is 30-60 mg every 4-6 hours, as indicated in the study 1.
- Codeine should be used with caution in patients with a history of substance abuse or respiratory depression.
- Non-opioid alternatives like dextromethorphan (10-15 mg every 6-8 hours) should be considered first, especially for children or those with respiratory conditions, as suggested by the guidelines 1.
- The use of local anesthetics, such as nebulized lidocaine, may be considered for patients with intractable cough that has not responded to other approaches, as suggested by the study 1.
It's crucial to weigh the benefits and risks of codeine treatment and consider alternative options, especially in patients with a history of substance abuse or respiratory depression. The guidelines 1 emphasize the importance of a comprehensive assessment and individualized treatment approach for patients with cough associated with lung cancer.
From the Research
Codeine Alone or in Combination with Caffeine for Cough Relief
- Codeine is a centrally acting narcotic opioid approved for use as an antitussive, and it has been widely regarded as the standard cough suppressant against which newer drugs are being evaluated 2.
- Codeine in combination with other medicines has been a mainstay for the effective short-term symptomatic relief of dry or nonproductive cough in clinical practice 2.
- A clinical trial comparing the effectiveness of three cough syrups found that codeine, dextromethorphan, and guaifenesin are equally effective in relieving cough symptoms 3.
- There is no direct evidence comparing codeine alone with codeine in combination with caffeine for cough relief, but a study on oral surgery pain found that the combination of acetaminophen, codeine, and caffeine was slightly better than acetaminophen alone 4.
- Caffeine is sometimes combined with other active ingredients, such as acetaminophen, phenylpropanolamine hydrochloride, guaifenesin, pseudoephedrine hydrochloride, chlorpheniramine maleate, and dextromethorphan hydrobromide, in cough and cold preparations, and a gas chromatographic method has been developed for the simultaneous determination of these ingredients 5.
Pharmacokinetics and Pharmacodynamics
- Codeine is bioactivated by CYP2D6 into morphine in the liver, and its opioid effects are related to plasma morphine concentrations 2.
- Dextromethorphan, another antitussive agent, has a complex metabolism involving sequential O-demethylation and N-demethylation, and its pharmacokinetics and pharmacodynamics can be affected by genotypic variations in enzymes and interactions with other drugs 6.