Zyrtec is a common over-the-counter antihistamine medication used to relieve allergy symptoms such as runny nose, sneezing, itchy or watery eyes, and itching of the throat or nose. While Zyrtec is generally considered safe for most people, it can still cause side effects in some individuals.

Common Side Effects of Zyrtec

  • Drowsiness: Zyrtec is known for its non-sedating properties, but some people may still experience drowsiness, especially when taking higher doses. It’s generally less sedating than older antihistamines like diphenhydramine.
  • Dry Mouth: Zyrtec can reduce saliva production, leading to a dry or uncomfortable feeling in the mouth.
  • Headache: Some individuals may experience mild to moderate headaches while taking Zyrtec.
  • Stomach Upset: Upset stomach, nausea, or diarrhea can occur in some people, although it is relatively uncommon.
  • Fatigue: While Zyrtec is less likely to cause drowsiness compared to some other antihistamines, it can still lead to fatigue or a feeling of tiredness in some users.
  • Dizziness: Dizziness is another less common side effect of Zyrtec.
  • Sore Throat: Some people may experience a sore or dry throat as a side effect.
  • Rash or Hives: In rare cases, Zyrtec itself can cause allergic reactions, including skin rash or hives. If you develop these symptoms, stop taking the medication and seek medical attention.
  • Difficulty Urinating: Zyrtec can occasionally cause difficulty urinating, especially in people with preexisting urinary problems.
  • Allergic Reactions: While uncommon, severe allergic reactions to Zyrtec can occur. Signs of a severe allergic reaction include difficulty breathing, swelling of the face, lips, tongue, or throat, and hives. Seek immediate medical attention if you experience these symptoms.
Zyrtec Side Effects

What is Zyrtec?

Zyrtec is one of the leading brands of Cetirizine HCI, manufactured and marketed by GSK Pharma Pakistan.

Zyrtec : Available Formulations and Strengths

Presently, Zyrtec is available in Tablets, Chewable Tablets, and Syrup Forms

Zyrtec Tablets : 5mg and 10mg Strengths

Zyrtec Chewable Tablets : 5mg and 10mg Strengths

Zyrtec Syrup : 1mg/ml

What Are The Possible Drug Interactions of Zyrtec?

  1. Alcohol: Combining Zyrtec with alcohol can increase the risk of drowsiness and dizziness. It’s generally best to avoid alcohol while taking Zyrtec.
  2. Central Nervous System Depressants: Other medications or substances that can cause drowsiness or central nervous system depression, such as sedatives, tranquilizers, and sleep aids, may enhance the sedative effects of Zyrtec.
  3. Other Antihistamines: Taking multiple antihistamines at the same time can increase the risk of side effects like drowsiness and dry mouth. It’s generally not recommended to use Zyrtec along with other antihistamines.
  4. CYP3A4 Inhibitors: Certain drugs that inhibit the activity of the enzyme CYP3A4 can increase the concentration of Zyrtec in the body, potentially leading to an increased risk of side effects. Examples of CYP3A4 inhibitors include ketoconazole, erythromycin, and cimetidine.
  5. Kidney Disease: If you have kidney disease, the elimination of Zyrtec from the body may be impaired, and it could potentially accumulate to higher levels. Your doctor may need to adjust your Zyrtec dosage if you have kidney problems.
  6. Diphenhydramine and Other First-Generation Antihistamines: While not a drug interaction in the traditional sense, it’s worth noting that Zyrtec is a second-generation antihistamine, which is generally preferred over first-generation antihistamines like diphenhydramine (Benadryl) because it is less sedating and has a lower risk of side effects. If you’re currently using a first-generation antihistamine, switching to Zyrtec may be advisable for better tolerability.