AJ is a female, age 65 years, who comes to the pharmacy counter asking to speak with a pharmacist. You approach the counter, and she hands you a bottle of loratadine. She says she thinks she got the wrong medication because she was expecting a pain pill and she saw in a commercial on TV that loratadine is an over-the-counter allergy medication. 
 
You look at the bottle and it says: loratadine 10 mg 1 qd x 5 day for bone pain.
 
Mystery: Why is was this customer prescribed an allergy medication when she was expecting a pain pill?
 

Solution: Loratadine is being used off-label for the treatment of breast cancer and bone pain for patients receiving chemotherapy and pegfilgrastim during each 5-day cycle of chemotherapy.
 
 
REFERENCE

Kirshner JJ, McDonald MC 3rd, Kruter F, et al. NOLAN: a randomized, phase 2 study to estimate the effect of prophylactic naproxen or loratadine vs no prophylactic treatment on bone pain in patients with early-stage breast cancer receiving chemotherapy and pegfilgrastim. Support Care Cancer. 2018;26(4):1323‐1334. doi:10.1007/s00520-017-3959-2