What side effects should I be expecting from taking loratadine?

Signs of loratadine 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). 

Call your doctor immediately if you experience any of the following symptoms:

• Severe headache
• Lightheadedness, feeling like you are about to faint
• Fast, uneven heart rate

Common side effects of loratadine:

• Feeling tired or drowsy
• Headache
• Nausea, vomiting 
• Stomach pain
• Being hyperactive or feeling jittery

Loratadine Overdose: Go to the nearest emergency room or call the Poison Help line at 1-800-222-1222. You can find more information at www.poisonhelp.org/help

Symptoms of loratadine overdose include:

• Severe headache
• Drowsiness 
• Somnolence 
• Fast or pounding heartbeat

The above list on this site may not include all the possible side effects of loratadine. 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