Why does claritin (loratadine) make me tired.i took one dose and it made me so sleepy.im 51 year old female.

Antihistamines: Antihistamines cause some people to be tired. They cause different levels of fatigue in different patients. If Claritin (loratadine) makes you drowsy, either take it at night, or try a different antihistamine like Allegra which is known not to cause fatigue in most

Common side effect: Although Claritin (loratadine) may have less drowsiness than other antihistamines, nonetheless this does vary, and seems that you are going to be challenged to tolerate. Other similar products may be less soporific, so work with your doctor to find the best approach.