What over-the-counter (OTC) medication is suitable for a patient with hypertension (high blood pressure) to use for a cough?

OTC Cough Medications for Patients with Hypertension

For patients with hypertension, menthol-based cough preparations are the safest first-line OTC option for cough relief, while dextromethorphan can be used as a second-line option with caution regarding dosing and combination products. 1

First-Line Options for Hypertensive Patients

Menthol-Based Products

• Menthol by inhalation effectively suppresses the cough reflex with minimal systemic effects 1
• Available as menthol crystals BPC or proprietary capsules
• Provides acute, short-lived cough suppression with minimal impact on blood pressure
• No significant drug interactions with antihypertensive medications

Simple Non-Pharmacological Options

• Honey and lemon mixtures (as recommended by Thorax guidelines) 1
• Adequate hydration with warm fluids
• These options have no impact on blood pressure control

Second-Line Options

Dextromethorphan

• Can be used with caution in hypertensive patients 1, 2
• Dosing considerations:
  • Standard OTC doses (15-30mg) are likely subtherapeutic
  • Maximum cough suppression occurs at 60mg 1
  • Use single-ingredient products to avoid problematic combinations

Guaifenesin (Expectorant)

• Safe in hypertension as it doesn't affect blood pressure 3
• Works by thinning mucus rather than suppressing cough
• Most effective for productive cough rather than dry cough

Medications to Avoid in Hypertension

First-Generation Antihistamines

• While effective for cough suppression, they can cause drowsiness 1
• May interact with some antihypertensive medications
• Use with caution, especially in elderly hypertensive patients

Combination Cold Products

• Many contain decongestants (pseudoephedrine, phenylephrine) that can raise blood pressure 1, 4
• The ACCP guidelines specifically recommend against using combination cold medications except those with older antihistamine-decongestant combinations 1

Codeine or Pholcodine

• Not recommended due to adverse side effect profile 1
• No greater efficacy than dextromethorphan
• May cause constipation which can indirectly affect blood pressure control

Special Considerations

ACE Inhibitor-Induced Cough

• If the patient is taking an ACE inhibitor, the cough may be medication-related 1, 5
• Occurs in 5-35% of patients on ACE inhibitors 1, 6
• Typically dry and associated with tickling sensation in throat
• More common in women, nonsmokers, and certain ethnic groups 1
• Management options:
  • Switch to an angiotensin receptor blocker (ARB) like losartan or valsartan 5
  • Cough typically resolves within 1-4 weeks after discontinuation 1

Monitoring Blood Pressure

• Monitor blood pressure when starting any new cough medication
• Avoid products containing pseudoephedrine or phenylephrine which can cause hypertensive crisis 7
• If using combination products, check all ingredients carefully

Algorithm for OTC Cough Treatment in Hypertension

1. Determine if cough is ACE inhibitor-related (if patient is on ACE inhibitor)

   • If yes, consult physician about switching to ARB
   • If no, proceed to step 2

2. Try non-pharmacological approaches first:

   • Honey and lemon mixture
   • Adequate hydration
   • Menthol-based products

3. If insufficient relief:

   • For dry cough: Single-ingredient dextromethorphan
   • For productive cough: Guaifenesin

4. Avoid:

   • Products containing decongestants
   • Combination cold products unless ingredients verified as safe
   • Codeine-containing products

By following this approach, patients with hypertension can safely manage their cough symptoms while maintaining blood pressure control.