 [ Symptoms ] can u take allegra d while taking z pack doctor says i have bronchitis he gave me a z pack can not sleep cus of drainage possible allergies [ Disease ] the d in allegra d is a decongestant that cause drainage especially if you take it near bedtime the antihistamine component in allegra is fine at bedtime so you may want to consider losing the d at bedtime a z pack azithromycin is compatible with this medication