You should not take Alavert if:

You are allergic to loratadine or to desloratadine (Clarinex). 
Ask a doctor or pharmacist if it is safe for you to take this medicine if you have:

• kidney disease; 
  Ask a doctor or pharmacist if it is safe for you to take this medicine if you have:

   

  • kidney disease;
  • liver disease.

  You should not take this medication if you are allergic to loratadine or to desloratadine (Clarinex).

  FDA pregnancy category B: This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Loratadine can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
  
  Loratadine disintegrating tablets (Claritin Reditab, Alavert) may contain phenylalanine. Talk to your doctor before using this form of loratadine if you have phenylketonuria (PKU).
  Do not give this medication to a child younger than 6 years old without the advice of a doctor.

All medicines may cause side effects, but many people have no, or minor, side effects.

Check with your doctor if any of these most common side effects persist or become bothersome:

• fast or uneven heart rate;
• feeling like you might pass out;
• jaundice (yellowing of your skin or eyes);
• seizures (convulsions).

Call your doctor at once if you noticed these serious side effects. Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects may include:

• headache;
• skin rash;
• nervousness;
• nosebleed;
• feeling tired or drowsy;
• eye redness, blurred vision;
• stomach pain, diarrhea;
• dry mouth, sore throat hoarseness.