Brief Answer:
An hour before you are planning to go to bed

Detailed Answer:
Welcome to Healthcaremagic.
Hi, I am Dr Anshul Varshney , I have read your query in detail , I understand your concern.
Endep contains Amitryptilline, which is a Tri-cyclic Anti depressant and is found to be useful in cases of back pain and neuropathic pain.
Now, this is not a sleeping pill but it usually causes sedation. Since you have been on Lyrica, that also causes severe sedation, you might not get much sedation from Endep.
In my opinion you should take Endep an hour before you go to bed, so that it gets on it's peak effect when you are trying to sleep.
Still, if you don't get a good sleep using it, write back to me in morning, and we will discuss the further course of action.
This is my personal opinion based on details available here. If you still have any other query, you may please ask me.
Stay Healthy.
Dr Anshul Varshney , MD

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