Roberta asked
Can I take Zyrtec and Claritin together?
Answer
Zyrtec (cetirizine) and Claritin (loratadine) are both second-generation antihistamines approved for the treatment of seasonal allergic rhinitis and chronic urticaria (a type of skin rash). They should not be taken together. Not only will combined use increase the risk of side effects such as constipation and sedation, there likely won't be any additional benefit when it comes to allergy symptom reduction.
Zyrtec and Claritin work the same way, by blocking the binding of histamine to H1 (histamine-1) receptors. By blocking the binding of histamine, it prevents allergic symptoms from occurring.
Both Zyrtec and Claritin bind fairly strongly to their respective receptors and taking both at the same generally does not result in increased receptor binding (as either Claritin or Zyrtec will be bound). Therefore, taking both is not therapeutically beneficial. You will most likely only have additive adverse reactions, which include:
- Sedation
- Constipation
- Dry eyes
- Dry mouth
- Cardiac problems (uncommon)
Both Zyrtec and Claritin may be taken with or without food and may be taken in the morning or in the evening. Each dose lasts around 24 hours.
