Can I take 2 tablets of extra strength 24-hour cetirizine hydrochloride instead of 1?

Yes, you can take 2 tablets of extra-strength cetirizine hydrochloride 24h instead of 1. However, it is recommended not to exceed a total of 10mg per day for over-the-counter medication and up to 20mg per day with a prescription. It is important to be cautious of possible side effects like headaches and drowsiness, which could increase with higher doses. If your allergy symptoms persist, it is advisable to consult a pharmacist or doctor for more effective solutions tailored to your specific symptoms.