Product description: Most people who suffer from allergies have outdoor and indoor allergies. Zyrtec is one of the only medications on the market that treats both. By blocking the action of histamines, the chemical in your body that causes allergies, Zyrtec provides up to 24 hours of relief from: itchy watery eyes, sneezing, runny nose, hives, and postnasal drip.

How to use this product: Follow your doctor's advice. Take Zyrtec exactly as prescribed. The normal suggested dose for adults is one 10 mg tablet daily. If you miss a dose of Zyrtec, take it as soon as you remember. If it's almost time for your next scheduled dose, skip it and continue with your regular dosing schedule.

Side effects: In clinical studies less than 3 percent of patients quit taking Zyrtec as a result of side effects. The most common side effects reported in clinical trials were drowsiness, fatigue, and dry mouth.

If you experience an allergic reaction during your treatment, stop taking Zyrtec and seek medical attention immediately. Symptoms of an allergic reaction include rash, itching, swelling, dizziness, and/or trouble breathing.

Precautions: Before you take Zyrtec, tell your doctor about any medical problems you have. You may require a lower dose or special monitoring during your treatment if you:

Use caution when driving or operating heavy machinery. Zyrtec has been known to cause drowsiness and dizziness in a small percentage of patients (less than 12%). Also, avoid drinking alcohol with Zyrtec. Alcohol increases drowsiness and dizziness.

Drug interactions: Before taking Zyrtec tell your doctor if you are using medicines for anxiety, sleep deprivation, or depression. Types of drugs other than those listed here may also interact with Zyrtec. That's why it's important to talk to your doctor and pharmacist before you begin treatment.