Changed from Pregabalin to Gabapentin

Hi, I have gained 4.5 stone in 4 years from being on Mirtazapine, Quetiapine and Pregabalin. I have managed to get off Mirtazapine and Quetiapine but still on 500mg Pregabalin over 2 doses. In an effort to shift weight, I have switched from Pregabalin to Gabapentin. 900mg over 3 doses. I feel awful. Depressed, tearful, nauseous and hopeless. How long should I wait to gauge how I am doing on Gabapentin? I am very worried and don't want to go back to being suicidal. Any advice appreciated. GP not much help. I know more than she does.
Thanks

Quote:

---

Originally Posted by Greycylinder

In an effort to shift weight, I have switched from Pregabalin to Gabapentin. 900mg over 3 doses. I feel awful. Depressed, tearful, nauseous and hopeless.

---

I'm not surprised as 900 mg gabapentin is well short of an equivalent dose to 500mg pregabalin. Not only is the dose likely to be ineffective, but there are probably some withdrawal symptoms too.

At low doses 50mg pregabalin would be about equal to 300mg gabapentin, however, gabapentin bioavailability drops rapidly as the dose increases. At 100mg about 80% of the med makes it into the bloodstream, but at 1,600mg only 27% does. So it is impossible to specify how much gabapentin you'd need to take to equal 500mg pregabalin, but it's almost certainly a lot more than 900mg. I think 2,100mg/day would likely to be the minimum starting point in finding the optimum dose and my guess is you'll need 2,700-3,000mg/day. I'm also not sure that switching to gabapentin will help that much in reversing weight gain, particularly at high doses.

Quote:

---

How long should I wait to gauge how I am doing on Gabapentin?

---

Gabapentin usually begins working quickly, within a day or two, but it's going to take you a while to find the optimum dose. Frankly, I think the better option is to stay on pregabalin and to tackle the weight gain by other means such as exercise (which is also great for anxiety and depression) and diet changes.

Quote:

---

I am very worried and don't want to go back to being suicidal.

---

Were you generally doing okay without mirtazapine and quetiapine until the current problems from switching between pregabalin and gabapentin?

Thank you so much for replying. Yes, I was a lot better on Pregabalin. I still had bad days but they had specific causes. I have booked a call with my GP this afternoon to discuss best options. This makes sense to me now. I haven't had a night's sleep since I started the Gabapentin either so I feel terrible. Thanks again.

Spoke to a different GP and I am back on Pregabalin. Will have to rethink the weight problem.