What happens if you accidentally take 2 claritins (loratadine) (10mg each) in 24 hours when you're supposed to only take one ? anything serious would happen ?

Extra Claritin (loratadine): If you are in generally good health with normal kidney and liver function, and you are not taking other sedating medications, there are not likely to be serious consequences. The worst you might experience would be excessive drowsiness, sedation, etc so don't drive for 24 hours. Also do not consume alcohol or take other medications that are CNS depressants for 48 hours.