What are Loratadine and Allegra?
Loratadine and Allegra are both popular over-the-counter (OTC) medications used to treat allergy symptoms such as sneezing, itching, watery eyes, and runny nose. They belong to a class of drugs known as second-generation H1-receptor antagonists, or antihistamines.
How Do They Work?
As second-generation antihistamines, both loratadine and Allegra work by blocking the effects of histamine, a chemical released by the body during an allergic reaction. By blocking histamine from binding to H1 receptors, they prevent or reduce the allergic response. A key feature of these newer antihistamines is that they are less likely to cause significant drowsiness compared to older, first-generation antihistamines (like Benadryl). They primarily target peripheral H1 receptors rather than crossing the blood-brain barrier.
Key Differences
While they function similarly, there can be subtle differences in how individuals respond to each medication, such as speed of onset or specific side effects. Some studies have suggested differences in potency or onset, but generally, they are considered to be in the same therapeutic class. Allegra (fexofenadine) has been noted for a potentially faster onset of action in some studies, while loratadine's active metabolite, desloratadine, may contribute to its effects over a slightly longer timeframe.
Why You Shouldn't Take Them Together
The primary reason for avoiding the combination of loratadine and Allegra is the lack of added therapeutic benefit coupled with a heightened risk of adverse effects. Since both drugs work in a similar way to block histamine, taking a double dose by combining them does not typically lead to better allergy symptom relief.
Increased Risk of Side Effects
Doubling up on oral antihistamines increases the overall load of the drug in your system. This can lead to synergistic effects, where the combined impact of the medications on your body is greater than the sum of their individual effects. While second-generation antihistamines are considered non-drowsy, high doses can still induce sleepiness, especially in sensitive individuals. Other potential side effects that may worsen when combining include:
- Dry mouth and dry eyes
- Headache
- Dizziness
- Rapid heart rate
- Gastrointestinal agitation
In rare and severe cases of overdose, particularly if other medications are involved, more serious complications can occur, such as cardiac arrest or seizures.
What if You Accidentally Take Both?
If you have accidentally taken both medications on the same day, it's generally recommended to skip the next scheduled dose as a precaution and monitor for any unusual symptoms. If you experience any severe side effects, seek immediate medical attention. For non-severe symptoms like mild drowsiness or dry mouth, waiting out the effect is often sufficient, but always consult a healthcare provider for personalized advice.
Comparison Table: Loratadine vs. Allegra
| Feature | Loratadine (Claritin) | Fexofenadine (Allegra) |
|---|---|---|
| Drug Class | Second-Generation Antihistamine | Second-Generation Antihistamine |
| Mechanism | Blocks H1 receptors, primarily metabolized to active desloratadine | Blocks H1 receptors, undergoes minimal metabolism |
| Onset of Action | Typically takes longer to reach peak effect than Allegra | Generally has a faster onset of action |
| Duration of Action | 24-hour relief | 24-hour relief |
| Drowsiness | Not typically sedating at recommended doses | Non-sedating at recommended doses |
| Potential Drug Interactions | Interacts with erythromycin, ketoconazole, and cimetidine | Interacts with certain fruit juices and antacids |
| Combination | Not recommended to combine with other oral antihistamines | Not recommended to combine with other oral antihistamines |
What to Do Instead of Combining Medications
If you find that your current oral antihistamine is not providing adequate relief, combining it with another oral antihistamine is not the solution. Here are some safer, more effective strategies to consider:
- Switch to a different single oral antihistamine. If one second-generation antihistamine is not working, your body may respond differently to another. Trying a different one like cetirizine (Zyrtec) or switching from loratadine to Allegra may provide better results.
- Add a different class of medication. Combining an oral antihistamine with a different type of allergy treatment, such as a nasal steroid spray like fluticasone (Flonase), can be highly effective. Nasal sprays and eye drops work locally to relieve specific symptoms and can be safely combined with oral medication.
- Consider combination products. Some products like Claritin-D or Allegra-D contain both an antihistamine and a decongestant (like pseudoephedrine), which can help with severe congestion. Always read the label carefully to ensure you are not double-dosing on any active ingredient.
- Consult a healthcare provider. For persistent or severe allergies, consulting a doctor or allergist is the best approach. They can help identify your specific triggers and recommend the most effective and safest treatment plan, which may include prescription medications or other therapies.
Conclusion
In short, while it may be tempting to try and boost allergy relief by combining loratadine and Allegra, it is not a safe or effective strategy. Both medications are designed to provide 24-hour relief by performing the same function in the body. Taking them together simply increases the risk of side effects like drowsiness and dry mouth without offering any added benefit. For optimal safety and symptom control, stick to one daily oral antihistamine. If your current medication isn't working, consider exploring other single-treatment options or adding a different class of allergy product, but always consult with a pharmacist or doctor to determine the best course of action.
