What oral medications can be used to treat allergic rhinitis?

Oral Medications for Allergic Rhinitis

Second-generation oral antihistamines (such as cetirizine, fexofenadine, loratadine, or desloratadine) are the primary oral medications for allergic rhinitis, though they are less effective than intranasal corticosteroids for moderate-to-severe disease. 1, 2

First-Line Oral Antihistamines

Second-generation oral antihistamines are strongly preferred over first-generation agents because they cause significantly less sedation, performance impairment, and anticholinergic effects (dry mouth, urinary retention). 1

Specific Second-Generation Options:

• Fexofenadine, loratadine, and desloratadine: No sedation at recommended doses 1
• Cetirizine: May cause sedation even at recommended doses 1
• All are effective for rhinorrhea, sneezing, and itching, but have limited objective effect on nasal congestion 1

Efficacy Profile:

• Most effective for: Sneezing, nasal itching, rhinorrhea 1
• Least effective for: Nasal congestion 1
• Additional benefit: Reduces allergic conjunctivitis symptoms 1
• Continuous use is more effective than as-needed dosing for seasonal or perennial allergic rhinitis 1

Leukotriene Receptor Antagonists (Montelukast)

Montelukast is approved for both seasonal and perennial allergic rhinitis and shows no significant efficacy difference compared to oral antihistamines (using loratadine as comparator). 1

When to Consider:

• Patients who also have asthma (approved for both conditions) 1
• Patients who prefer oral medication over intranasal options 3
• However, montelukast is less effective than intranasal corticosteroids 3, 4
• Side effects are minimal 1

Oral Decongestants

Pseudoephedrine or phenylephrine can be added for nasal congestion, though they come with important caveats. 1

Key Considerations:

• Effective for: Reducing nasal congestion in both allergic and nonallergic rhinitis 1
• Side effects: Insomnia, irritability, palpitations, potential blood pressure elevation 1
• Use with caution in: Hypertensive patients (monitor blood pressure), elderly, young children, and those with cardiac arrhythmia, angina, cerebrovascular disease, bladder obstruction, glaucoma, or hyperthyroidism 1

Oral Corticosteroids

A short course (5-7 days) of oral corticosteroids may be appropriate only for very severe nasal symptoms, but this should be discouraged as routine treatment. 1

• Preferred over intramuscular corticosteroids, which should be avoided 1

Critical Treatment Algorithm

For Mild Intermittent or Mild Persistent Allergic Rhinitis:

• Start with: Second-generation oral antihistamine (cetirizine, fexofenadine, desloratadine, loratadine) 2
• Alternative: Intranasal antihistamine (azelastine, olopatadine) 2

For Moderate-to-Severe Persistent Allergic Rhinitis:

• Do NOT start with oral medications alone 2
• Intranasal corticosteroids (alone or combined with intranasal antihistamine) are superior 1, 3, 2, 4
• Adding oral antihistamines to intranasal corticosteroids provides no additional benefit 3, 5

If Nasal Congestion is Prominent:

• Consider adding oral decongestant (pseudoephedrine) to antihistamine 1
• Monitor for cardiovascular side effects 1

Common Pitfalls to Avoid

• Do not use first-generation antihistamines (diphenhydramine, chlorpheniramine) as they cause unperceived performance impairment and sedation 1
• Do not expect oral antihistamines to effectively treat nasal congestion—they have minimal objective effect on this symptom 1
• Do not add oral antihistamines to intranasal corticosteroids expecting better control—evidence shows no benefit 3, 5
• Avoid oral decongestants in children under 6 years due to safety concerns including fatalities from overdose 1
• Do not prescribe oral medications as monotherapy for moderate-to-severe disease—intranasal corticosteroids are significantly more effective 3, 4