Treatment of Post Nasal Drainage in Adults
Start immediately with a first-generation antihistamine/decongestant combination (such as dexbrompheniramine plus sustained-release pseudoephedrine or azatadine plus sustained-release pseudoephedrine) as the most effective evidence-based first-line treatment for post nasal drainage, now termed Upper Airway Cough Syndrome (UACS). 1
Understanding the Condition
Post nasal drainage is the most common cause of chronic cough in adults and represents drainage of secretions from the nose or paranasal sinuses into the pharynx. 1, 2 Importantly, approximately 20% of patients have "silent" post nasal drip with no obvious symptoms of drainage yet still respond to treatment directed at the upper airway. 1, 2 This means you cannot rely on the patient's subjective sensation of drainage to make or exclude this diagnosis.
First-Line Treatment Algorithm
Initial Therapy (Days 1-14)
Prescribe a first-generation antihistamine/decongestant combination for 1-2 weeks. 1 Specific effective combinations include:
- Dexbrompheniramine maleate plus sustained-release pseudoephedrine sulfate 1
- Azatadine maleate plus sustained-release pseudoephedrine sulfate 1
To minimize sedation, start with once-daily dosing at bedtime for a few days before increasing to twice-daily therapy. 1 Most patients will see improvement within days to 2 weeks of initiating therapy. 1
Critical point: First-generation antihistamines are superior to newer non-sedating antihistamines for post nasal drainage due to their anticholinergic drying properties. 1 Newer-generation antihistamines are ineffective for non-allergic causes of post nasal drainage. 1, 2
If No Response After 1-2 Weeks
Add intranasal corticosteroids (fluticasone 100-200 mcg daily) for a 1-month trial. 1, 2, 3 Intranasal corticosteroids are effective for both allergic and non-allergic rhinitis-related post nasal drainage. 1 The FDA label indicates that maximum effect may take several days, with some symptom decrease occurring as soon as 12 hours after treatment. 3
Alternative for Patients with Contraindications
For patients who cannot tolerate decongestants (hypertension, cardiovascular disease, glaucoma), use ipratropium bromide nasal spray (42 mcg per spray, 2 sprays per nostril 4 times daily) as an alternative. 1 This provides anticholinergic drying effects without systemic cardiovascular side effects. 1
Adjunctive Therapy
Recommend high-volume nasal saline irrigation (150 mL) twice daily. 1 Nasal saline irrigation is more effective than saline spray because irrigation better expels secretions through mechanical removal of mucus, enhanced ciliary activity, and disruption of inflammatory mediators. 1
When to Escalate Treatment
If symptoms persist despite adequate upper airway treatment for 2 weeks, proceed with sequential evaluation for other common causes of chronic symptoms:
- Asthma/non-asthmatic eosinophilic bronchitis - Consider bronchial provocation testing if spirometry is normal 1
- Gastroesophageal reflux disease (GERD) - Initiate empiric therapy with omeprazole 20-40 mg twice daily before meals for at least 8 weeks plus dietary modifications 1
Upper airway cough syndrome, asthma, and GERD together account for approximately 90% of chronic cough cases, and these conditions often coexist. 1 Therefore, maintain all partially effective treatments rather than discontinuing them prematurely. 1
Specific Scenarios
If Allergic Rhinitis is Confirmed
Add intranasal corticosteroids immediately alongside the antihistamine/decongestant combination. 1 A 1-month trial of fluticasone 100-200 mcg daily is recommended. 1, 2 For refractory cases, consider adding intranasal antihistamine (azelastine or olopatadine) to the intranasal corticosteroid. 1
If Purulent Nasal Discharge Persists Beyond 10 Days
Consider acute bacterial sinusitis only if symptoms persist beyond 10 days without improvement, or if there is "double worsening" (initial improvement followed by worsening). 4, 1 Yellowish-green nasal discharge does NOT indicate bacterial infection requiring antibiotics during the first week of symptoms, as purulent discharge is typical of viral infections. 1
If Sinus Imaging Shows Abnormalities
Air-fluid levels on imaging indicate acute bacterial sinusitis requiring antibiotics. 1 However, mucosal thickening less than 8mm is associated with sterile nasal puncture in 100% of cases and does not automatically require antibiotics. 1
Critical Side Effects to Monitor
Common side effects of first-generation antihistamines include dry mouth and transient dizziness. 1, 2 More serious side effects requiring monitoring include:
- Insomnia, urinary retention, jitteriness 1, 2
- Tachycardia and worsening hypertension (monitor blood pressure after initiating decongestant therapy) 1
- Increased intraocular pressure in glaucoma patients 1
Common Pitfalls to Avoid
Never use topical nasal decongestants (oxymetazoline, xylometazoline) for more than 3-5 consecutive days due to the risk of rhinitis medicamentosa (rebound congestion). 1, 2 This is a critical error that worsens the underlying condition.
Do not rely solely on physical examination findings. 1 The absence of cobblestoning or visible secretions does not rule out post nasal drainage, as approximately 20% of patients have completely normal-appearing pharyngeal examination yet still respond to treatment. 1
Do not confuse GERD with post nasal drainage. 1 Both can cause pharyngeal inflammation and throat symptoms; GERD may mimic or coexist with post nasal drainage. If symptoms persist despite adequate upper airway treatment, empiric GERD therapy should be initiated. 1
Expected Timeline
Complete resolution may take several weeks to a few months. 1 If no response after 2 weeks of adequate treatment, proceed with sequential evaluation for other causes rather than continuing ineffective therapy. 1