Which patients should avoid using Halls (menthol cough drops)?

Contraindications and Precautions for Halls Menthol Cough Drops

Patients Who Should Avoid Menthol Cough Drops

Patients taking warfarin or other anticoagulants should avoid menthol cough drops due to documented drug interactions that can significantly decrease INR values and compromise anticoagulation control. 1, 2

Absolute Contraindications

• Patients on warfarin therapy: Menthol has been shown to decrease INR values from therapeutic ranges (2.28-2.68) to subtherapeutic levels (1.45-1.6), requiring substantial warfarin dose adjustments 1, 2

  • The mechanism likely involves menthol's effects on cytochrome P450 isoenzymes, either inducing or inhibiting metabolism of warfarin 1, 2
  • This interaction can persist for weeks with regular use (8-10 drops daily) 2

• Patients taking MAO inhibitors: Over-the-counter preparations containing sympathomimetic compounds should be avoided in patients on MAOIs, and menthol-containing products fall into this category of caution 3

Relative Contraindications and Cautions

• Patients with persistent or chronic cough: Higher menthol consumption is independently associated with worse cough severity (R = 0.21; P = .001), suggesting that excessive use may paradoxically exacerbate rather than relieve cough symptoms 4

  • Significant correlations exist between cough severity and: average menthol dose per drop (R = 0.19; P = .007), number of drops consumed daily (R = 0.2; P = .002), and total daily menthol intake (R = 0.21; P = .001) 4

• Patients with productive cough: Antitussive agents including menthol should be avoided when clearance of secretions is beneficial, as suppressing the cough reflex may impair mucus clearance 5

Clinical Pitfalls to Avoid

Common Prescribing Errors

• Underestimating over-the-counter product use: Patients often fail to report OTC cough drop use, with over 282 million menthol cough drops sold annually in the United States 4

  • Always specifically ask about cough drop use in patients with persistent cough or unexplained INR changes 1, 2

• Assuming menthol is benign: While menthol provides acute but short-lived cough suppression through inhalation, excessive consumption via cough drops may worsen symptoms rather than improve them 5, 4

Monitoring Requirements

• For anticoagulated patients: If menthol cough drops are inadvertently used, monitor INR closely and expect potential need for warfarin dose adjustments of 15-25% 1, 2
  • INR stabilization may take 5 days after discontinuing menthol products 2

Preferred Alternatives

For patients requiring cough suppression who have contraindications to menthol:

• First-line: Simple home remedies like honey and lemon are as effective as pharmacological treatments for benign viral cough 5, 6

• Second-line: Dextromethorphan 30-60 mg provides superior cough suppression with better safety profile than menthol drops 5, 6

  • Maximum cough reflex suppression occurs at 60 mg doses 5, 6

• For nocturnal cough: First-generation sedating antihistamines are particularly suitable due to their sedative properties 5, 6