Is It Safe To Give Singulair And Claritin At Once To Children?

hi my doctor has said that my granddaughter can have the 4-6 hour Sudefed with her claritan and Singular allergy meds. I wasn't thinking and gave her a 12 hour pill that says not for children under 12. She is 8 and weighs 83 lbs. Will it be a problem by itself and can I give her her singular and Claritan at bedtime. she took it at 5:30pm goes to bed at 8:30.