Should You Stop Desloratadine?
No, you should not stop desloratadine—the dry mouth is almost certainly caused by the pseudoephedrine in Nurofen Cold and Flu, not the desloratadine. The pseudoephedrine is the culprit and should be discontinued if the dry mouth is bothersome, while desloratadine can be safely continued for your allergic symptoms.
Understanding the Source of Dry Mouth
Dry mouth is a well-established side effect of pseudoephedrine (the decongestant component), not desloratadine. 1
- Pseudoephedrine causes dry mouth through its α-adrenergic agonist effects, which can produce anticholinergic-like side effects including dry nasal membranes, dry mouth, insomnia, irritability, and palpitations 1
- In controlled studies of first-generation antihistamine/decongestant combinations, dry mouth was specifically more common in the drug group, attributed to the decongestant component 1
- Desloratadine at recommended doses (5mg once daily) does not cause sedation and has minimal anticholinergic effects compared to first-generation antihistamines 1
Desloratadine's Safety Profile
Desloratadine is one of the safest second-generation antihistamines with an excellent tolerability profile:
- Fexofenadine, loratadine, and desloratadine do not cause sedation at recommended doses 1
- The most common side effects of desloratadine in clinical trials were sore throat, dry mouth (minimal), muscle pain, tiredness, sleepiness, and menstrual pain—but the overall incidence of adverse events was not significantly different from placebo 2, 3, 4
- In postmarketing surveillance of 77,880 subjects, only 0.37% reported any adverse events, with fatigue (0.07%), headache (0.07%), dry mouth (0.04%), and nausea (0.03%) being most common 3
- Tolerability was rated as excellent/good by 99.1% of investigators and 98.5% of subjects 3
Clinical Decision Algorithm
Here's what you should do:
Stop the Nurofen Cold and Flu (pseudoephedrine) if dry mouth is bothersome—this is the source of your symptom 1
Continue desloratadine 5mg once daily for your allergic rhinitis symptoms (sneezing, runny nose, itching) 2, 5, 6
If nasal congestion is your primary concern, consider these alternatives to pseudoephedrine:
- Intranasal corticosteroids are the most effective medication class for all symptoms of allergic rhinitis, including nasal congestion, and should be your first choice 1
- Topical nasal decongestants (oxymetazoline) for short-term use (≤3 days maximum) to avoid rhinitis medicamentosa 1, 7
- Intranasal antihistamines (azelastine) have clinically significant effects on nasal congestion and can be used as first-line treatment 1
If you need both antihistamine and decongestant effects, desloratadine combined with pseudoephedrine is effective, but you must weigh the benefit against the dry mouth side effect 8
Important Caveats About Pseudoephedrine
Be aware of additional concerns with pseudoephedrine:
- It can cause insomnia, difficulty with urination (especially in older men), jitteriness, tachycardia or palpitations, and worsening of hypertension 1
- Elevation of blood pressure occurs rarely in normotensive patients but occasionally in those with controlled hypertension—hypertensive patients should be monitored 1, 7
- Pseudoephedrine should be used with caution in patients with cardiac arrhythmia, angina pectoris, cerebrovascular disease, hypertension, bladder neck obstruction, glaucoma, or hyperthyroidism 1
Why Desloratadine is Worth Continuing
Desloratadine offers specific advantages beyond simple antihistamine effects:
- It has decongestant activity that has been corroborated in several studies—comparable to pseudoephedrine in one trial 5, 6
- It demonstrates anti-inflammatory effects that may benefit patients with coexisting asthma, reducing asthma symptoms and β2-agonist use 5, 4
- It has rapid onset of effect with sustained efficacy throughout a 24-hour dosage interval 5, 4
- It can be administered without regard to food intake and has negligible potential for drug interactions 5, 4