What side effects should I expect from taking cetirizine hydrochloride?

Signs of cetirizine allergy: Difficulty breathing, hives (rash on your body), swelling of the face, lips, tongue, or throat—If you experience any of these symptoms, please call 911 or seek emergency medical help at the nearest emergency room (ER). 

Stop taking cetirizine hydrochloride and call your doctor immediately if you experience any of the following signs:

• Weakness, tremors, malaise
• Insomnia (sleep problems)
• Fast, pounding, or uneven heartbeat
• Confusion, hallucinations
• Hyperactivity, severe restlessness
• Problems with vision
• Unusual change in urine output (from normal to little or no urination)

Common side effects of cetirizine hydrochloride:

• Tiredness, drowsiness, lightheadedness
• Feeling hot, unusually excessive sweating
• Numbness, tingling, “pins and needles,” or burning feeling 
• Lost sense of taste 
• Headache 
• Dry mouth
• Sore throat 
• Upset stomach, nausea, constipation

Less common side effects of cetirizine hydrochloride:

• Acid or sour stomach
• Belching 

Cetirizine Overdose: Seek emergency medical attention or call the local poison control center at 1-800-222-1222 if you think you take too much cetirizine. You can find more information at www.poisonhelp.org/help.

Cetirizine overdose can cause serious symptoms such as extreme drowsiness, agitation, pounding heartbeat, feeling restless then drowsy and malaise, nausea, vomiting, stomach pain, trouble breathing, speaking or swallowing, trouble walking. 

The above list on this site may not include all the possible side effects of cetirizine. Speak to your doctor or pharmacist at your local pharmacy if you have persistent side effects or any side effects that are not listed above. You can also report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088.

Source: FDA