Gabapentin may help relieve pain for Peter James. Additionally, be sure to warn Peter James about the dangers of increasing the amount of acetaminophen he may be taking as he weans himself off oxycodone. Learn more below.
Neuropathic pain like phantom limb pain can be treated with Gabapentin. Peter James does not currently take Gabapentin.
Advantage: no anticholinergic side effects, no hepatic metabolism, no cardiac toxicity.
Disadvantage: slow titration, three times per day dosing, non-linear kinetics.
As Peter James weans himself off oxycodone, he may be tempted to take more acetaminophen. Peter James needs to be warned about the maximum dose for acetaminophen and its associated liver damage risk.
Peter James takes Zolpidem and Oxycodone regularly instead of “as needed.” With that in mind, the following represent recommended changes to Peter James’ medication regimen.
Dr. Kent confers with the pharmacist.
The pharmacist tells Dr. Kent, “My other recommendation is to start some prazosin. When I was talking to his psychologist, I know he had a discussion with the patient about using prazosin, which can help with PTSD induced nightmares.”
Dr. Kent says, “You know, I think that sounds great. I would have normally used it as an anti-hypertensive but if it can help with some of his PTSD, I’d like to hear more about that.”
The pharmacist replies, “Sure. So they found in studies that it kind of helps decrease that CNS hyperexcitability that happens when patients with PTSD are trying to fall asleep. And this may also help with his blood pressure. So we can use one medication for two indications.”
Dr. Kent responds, “That sounds great. I haven’t used it for this particular indication before. How would you normally titrate it in this context?”
The pharmacist answers, “Sure. So we would start him at one milligram at bedtime, and titrate by one milligram a week. And the maximum dose in the trials was around fifteen milligrams. After patients are on five milligrams, then we tend to split the dose. So they would take one of their doses around dinner time, late afternoon, and they take the other dose at bedtime.”
Dr. Kent thanks the pharmacist by saying, “That’s very helpful. I wouldn’t have known how to dose this for that particular indication. So thank you.”
The pharmacist cautions, “One thing that we want to make sure that he is counseled on is the risk of orthostatic hypotension. I know that he’s gonna have some, you know, inclination where he might be a higher fall risk given his amputation. And this does cause orthostatic hypotension.”
“So he’s gonna need to take a few extra minutes getting out of chairs or getting out of bed in the morning just to have some compensation for that.”
Dr. Kent tells the pharmacist, “You know, I made a note about that. We’ll be sure to give him some counseling about that.”
Replace Fluoxetine with Duloxetine
The pharmacist begins by saying, “Right now Peter James is on fluoxetine for PTSD. But looking at his chart, I also saw that he has neuropathic pain. So I’d like to switch him to duloxetine because that will help both his neuropathic pain and there’s literature supporting its use for PTSD.”
Dr. Kent responds, “You know, I saw that as an attractive thing to do, too. So that sounds great to me.”
The pharmacist says, “So I’d start the duloxetine thirty milligrams once a day. And then we’re gonna need to slowly taper his fluoxetine because it has a very long half-life. Right now he’s taking forty milligrams a day. I would decrease it to twenty milligrams once a day for one week. Then ten milligrams once a day for a week. Then ten milligrams every other day for a week. And then I would stop it.”
Dr. Kent replies, “That sounds good. I think he’ll be very receptive to this and we’ll probably go ahead and initiate all three of these adjustments we’ve talked about (so far).”
Begin Polyethylene Glycol
The pharmacist remarks, “I noticed that he doesn’t have a bowel regimen scheduled and that he’s also taking the oxycodone. So I would start him on some polyethylene glycol, seventeen grams once a day mixed in eight ounces of water. (This is) to…try to minimize constipation with the opioids."
Dr. Kent says, “Absolutely. I’ll have the nurse call him regarding that.”
Reduce Oxycodone Dosage
The pharmacist asks, “Do you have any other questions for me, or concerns?”
Dr. Kent replies, “You know, Kate, I think long term another big issue is going to be working down off the relatively high doses of oxycodone that he’s been on. I do think that’s probably going to be a slow process for him. Ultimately that is another issue that we’re going to have to address in his care.”
“I think we probably have enough to work on today. That might be a back burner issue that you and I can tease out in coming visits.”
The pharmacist responds, “That sounds like a good plan to me.”