### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
Hi, I am a 59-year-old male with Guillain-Barre Syndrome who is suffering from extreme, constant pain.  I am currently taking Percocet 10-325 four times a day, however this is not helping.  The main problem I am encountering is the both the strength of the medication and duration that the medication lasts for.  I have spoken to my doctor about this problem, and he gave me a choice of several other pain relief medications that I can try.  They are Oxycodone, Oxycontin supplemented with Percocet, and MS Contin.  I am wondering which of these medications would have the longest duration of pain relief, while at the same time delivering a stronger effect than the Percocet I am currently taking.  As an aside, I have had both Percocet 10-325 and Oxycodone 10 available to me at the same time due to a prescription mix up.  When these two medications were taken together, they alleviated my pain completely for more than the 6 hour time period that the dose was supposed to perform for, and allowed me to take regular Percocet 10-325 for the rest of the day without any significant increase in pain.  However, this solution in and of itself has not been something that has worked as well as I hoping it would work.My question is, of the options I have been offered, keeping in mind they are the only ones available to me at this given time, I need to know not only which would be the most efficient and longest lasting, but also, mot probably the safest.I would also like to add that during two recent visits to the hospital, each of which lasted one week, I was given 4 mg of morphine every 6 hours with no ill effects whatsoever.Thank you for any advice you can offer.

### output:

Hi, Thank you for posting your query. It is unfortunate that you are suffering from severe pain, following Guillain Barre syn Chat Doctor. I see many patients with GBS and about half of them have severe neuropathic pain. Most of them get better with pregabalin and gabapentin. So, I would suggest you try one of these, if you have not taken them earlier. Otherwise, percent is fine. Please get back if you require any additional information. Best wishes,