Can loratadine (Claritin) and fexofenadine (Allegra) be taken together for allergic rhinitis?

Do Not Combine Loratadine and Fexofenadine for Allergic Rhinitis

You should not take loratadine (Claritin) and fexofenadine (Allegra) together—there is no evidence supporting benefit from combining two oral antihistamines, and doing so only increases cost and potential side effects without improving symptom control.

Why This Combination Makes No Sense

Both loratadine and fexofenadine are second-generation oral H1-antihistamines that work through the same mechanism—blocking histamine receptors 1. Taking them together provides no additive benefit because:

• They target the same receptor pathway: Once H1 receptors are blocked by one antihistamine, adding another provides no additional blockade
• No guideline recommends this approach: The 2008 AAAAI/ACAAI practice parameters extensively discuss combination therapies but never suggest combining two oral antihistamines 1
• Research shows comparable efficacy: Studies directly comparing fexofenadine and loratadine show they have similar effectiveness, with no rationale for combining them 2, 3

What You Should Do Instead

If One Antihistamine Isn't Working:

Switch to a different antihistamine rather than adding a second one. Research shows that patients who don't respond to one antihistamine may respond to another 3. Among second-generation antihistamines:

• Fexofenadine and loratadine are non-sedating at recommended doses 1
• Fexofenadine may be slightly more effective for eye symptoms and nasal congestion compared to loratadine 2
• If switching doesn't help, the problem isn't the antihistamine choice—you need a different medication class

If Symptoms Remain Inadequately Controlled:

Step up to intranasal corticosteroids (INCS), which are the most effective monotherapy for allergic rhinitis 1, 4. The evidence hierarchy is clear:

1. First-line for moderate-to-severe symptoms: Intranasal corticosteroids alone (fluticasone, mometasone, etc.) 4, 5
2. For mild symptoms: Oral antihistamine monotherapy is reasonable 1
3. For rapid onset needs: Consider adding intranasal antihistamine (azelastine) to INCS for moderate-to-severe disease 4, 5

Evidence-Based Combination Approaches:

If monotherapy with an oral antihistamine fails, guidelines support these combinations—but never two oral antihistamines 1:

• INCS + intranasal antihistamine: May provide faster onset than INCS alone, particularly useful for moderate-to-severe seasonal allergic rhinitis 4, 5
• Oral antihistamine + oral decongestant (pseudoephedrine): More effective for nasal congestion than antihistamine alone 1
• INCS alone is generally preferred over INCS + oral antihistamine: The 2017 US practice parameters strongly recommend INCS monotherapy rather than combination with oral antihistamine for initial treatment 4

Important Caveats

Adding an oral antihistamine to intranasal corticosteroids provides minimal additional benefit 6. A well-designed study showed that mometasone furoate nasal spray plus loratadine was no more effective than mometasone alone 6. The guideline evidence notes that "supporting studies are limited and many studies are unsupportive of additive benefit of adding an antihistamine to an intranasal steroid" 1.

Both fexofenadine and loratadine are non-sedating at recommended doses 1, so sedation is not a reason to prefer one over the other or combine them.

The Bottom Line Algorithm

1. Start with one oral antihistamine (loratadine OR fexofenadine, not both)
2. If inadequate response after 1-2 weeks: Switch to the other antihistamine OR step up to intranasal corticosteroid
3. For moderate-to-severe symptoms from the start: Begin with intranasal corticosteroid monotherapy 4
4. If INCS alone insufficient: Add intranasal antihistamine (not oral) for faster/better control 4, 5
5. Never combine two oral antihistamines—no evidence supports this approach