What is a good cough medicine for an adult with a common cold or allergies, considering potential interactions with pseudophedrine, especially for those with hypertension?

Pseudoephedrine-Containing Combination Products Are Effective for Cough and Congestion

For adults with common cold or allergies, a first-generation antihistamine combined with pseudoephedrine (such as brompheniramine/pseudoephedrine or diphenhydramine/pseudoephedrine) is the most effective evidence-based option for cough relief, particularly when cough is accompanied by nasal congestion. 1 Adding dextromethorphan provides additional cough suppression. 1, 2

Recommended Medication Combinations

First-Line: Antihistamine/Decongestant Combinations

• Brompheniramine (sustained-release) plus pseudoephedrine is specifically recommended by ACCP guidelines for cough due to upper respiratory infections, as it addresses the postnasal drip mechanism that drives most viral URI coughs. 1
• Diphenhydramine 25-50 mg plus pseudoephedrine 60-120 mg every 4-6 hours (maximum 4 doses/24 hours) is an alternative first-generation antihistamine/decongestant combination effective for cold symptoms. 1, 3
• First-generation antihistamines work through their anticholinergic properties, not just histamine blockade, which is why newer non-sedating antihistamines (loratadine, cetirizine) are ineffective for common cold cough. 1, 3

Adding Cough Suppressants

• Dextromethorphan can be added for additional cough suppression in chronic bronchitis, though evidence for acute URI cough is more limited. 1, 2
• Codeine is recommended only for chronic bronchitis, not for URI-related cough. 1

Critical Considerations for Pseudoephedrine Use

Blood Pressure Effects

• Pseudoephedrine causes a modest average increase of 1 mmHg systolic blood pressure and increases heart rate by 2-3 beats/minute in the general population. 4
• Patients with controlled hypertension can generally use pseudoephedrine safely at standard doses with blood pressure monitoring, as therapeutic doses (60 mg four times daily) do not adversely affect blood pressure control in selected hypertensive patients. 4, 5
• Avoid pseudoephedrine entirely in patients with uncontrolled hypertension, severe cardiovascular disease, cerebrovascular disease, hyperthyroidism, closed-angle glaucoma, or bladder neck obstruction. 1, 4, 3

Important Safety Warnings

• Never combine multiple sympathomimetic decongestants (oral plus topical), as this can precipitate hypertensive crisis. 6, 4
• Avoid concurrent caffeine or stimulant medications (including ADHD medications), as these produce additive adverse effects including elevated blood pressure, insomnia, and palpitations. 1, 4, 3

Alternative Options for Hypertensive Patients

Safer Decongestant Alternatives

• Intranasal corticosteroids are the safest first-line option for nasal congestion in hypertensive patients, with no cardiovascular effects. 1, 4
• Topical nasal decongestants (oxymetazoline, xylometazoline) cause primarily local vasoconstriction with minimal systemic absorption, but must be limited to ≤3 days to avoid rhinitis medicamentosa. 1, 4
• Phenylephrine oral formulations are ineffective due to extensive first-pass gut metabolism and should not be substituted for pseudoephedrine. 1, 4

Non-Decongestant Options

• Nasal saline irrigation provides modest benefit for symptom relief without any cardiovascular risk. 1, 4
• Second-generation antihistamines alone (loratadine, cetirizine) are safe in hypertension but ineffective for common cold cough—they work only when significant allergic component exists. 1, 4

Common Pitfalls to Avoid

• Do not use antihistamines in non-allergic patients expecting significant benefit—they primarily help when allergic rhinitis coexists. 1
• Guaifenesin (expectorant) has no proven efficacy for symptomatic relief of acute respiratory infections. 1
• Antibiotics have no role in treating common cold symptoms. 7
• Newer non-sedating antihistamines are ineffective for cold-related cough because they lack the anticholinergic properties needed to reduce secretions. 1, 3

Practical Dosing Algorithm

For normotensive adults or those with controlled hypertension:

• Start with brompheniramine/pseudoephedrine sustained-release combination twice daily, or diphenhydramine 25-50 mg plus pseudoephedrine 60 mg every 4-6 hours. 1, 3
• Add dextromethorphan 10-20 mg every 4-6 hours if cough persists despite antihistamine/decongestant. 2, 8
• Monitor for insomnia, irritability, or palpitations—common side effects requiring dose reduction or discontinuation. 1, 3

For patients with uncontrolled hypertension:

• Use intranasal corticosteroids as primary therapy. 4
• Consider short-term topical decongestant (≤3 days) if severe congestion. 4
• Avoid all oral sympathomimetics entirely. 4