the 100mg pregabalin to 600mg gabapentin is the correct conversion, straight from the original lyrica manufacturer. if you want to use gabapentin to come off, i’d recommend tapering that dose instead of switching then just jumping off.
gabapentin has major diminishing returns in bioavailability and it’s transporters get full quick. when taking a 300mg pill, roughly only 150mg gets absorbed. out of a 600mg pill, only 250mg gets absorbed. at 1200mg only 400mg gets absorbed. gabapentin is best absorbed when taking 300mg every 30 minutes. to maximize your doses and minimize withdrawal, i’d recommend something like this
Day 1-3:
Total 1200mg gabapentin, taking 300mg every 30min starting when you’d take your first pregabalin dose. 300mg for every 50mg of pregab.
(i.e. If you took 100mg pregabalin at 12:00pm, take 300mg gabapentin at 12:00pm, then 300mg again at 12:30pm. If you were taking 200mg pregabalin all at once at 12:00pm, take 300mg gabapentin at 12:00pm, 300mg at 12:30, 300mg at 1:00pm, 300mg at 1:30pm. If taken in 4 different 50mg doses, take 300mg at each dose)
Day 4-7:
Total 900mg gabapentin (equating to 150mg pregab) taking 300mg every 30min when you would start taking your doses, the same schedule as the first couple days, just leaving out the last 300mg.
Days 8-10:
Total 600mg gabapentin (equal to 100mg pregab) taking 300mg every 30min at your starting dose. If you were taking your pregabalin in two separate doses, take 300mg at the first dose, 300mg at the second dose.
Days 11-14:
Total 300mg, taking it at whichever dose you prefer.
Then you’re done! Now, you absolutely could just take 1200mg daily for 2 weeks then hop off. While I’ve never withdrawn from gabapentin, when i missed doses of my Rx pregabalin it felt awful. so, as long winded as i may be, i hope this helps. this schedule should at least mitigate any withdrawal symptoms you may have. if you don’t have dose timings and just kinda took em whenever, just space it out thru the day however feels the most comfortable.
