Is it dangerous to take tricyclic antidepressants and antihistamines together?

I'm currently taking Norpramin (Desipramine), which is an anticholinergic medication for depression and anxiety and Benadryl for my allergies. Both drugs are anticholnergic medications, in which taking a certain amount can be dangerous, so it's easy to overdose. I'm on a low dose of Norpramine. How dangerous is it for me to take Benadryl along with it?