It would help to know the name of the other drug.
The short answer to your question is that they all can potentiate each other. In other words, dependency of one may be due to the others. The clinical effectiveness of one may be lessened or heightened by the others. The data is not clear but does indicate interaction amongst the drugs you have listed.
Ambien is not FDA approved for long term use. A doctor can do this using "off labeled" needs.
Why the Topamax? --> Seizures? Cluster headaches? Migraines? Chronic pain syndrome? This drug may not be needed.
For pregnancy :Topamax does cause cancer & birth defects in animals & is not recommended in humans. Lexapro is also not recommended but the human is literature is limited. The dose is suggested should be tapered in the 3rd trimester & rebolused post delivery for high risk of post-partum depression. Ambien did not cause any effects in animals but humans born to mothers taking sedatives can be addicted themselves.
As for breast feeding all of these drugs are not recommended.
Realize the literature on this is limited since it is unethical to trial on humans. So most of this is post marketing experience.
8 yrs for depression 5yrs for a sleep disorder these are long time intervals for these without any significant porgress?? You may be in for some problems that are unpleasant to talk about. I would suggest marriage counseling or a program called relationship rich done in Dallas Texas. http://www.relationshiprich.com/ excellent discovery process. be careful getting married is easy getting out of it is not.
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