How likely is weight gain on 600 mg pregabalin vs lower doses?

The short version: weight gain on pregabalin is dose-related, and 600 mg is the highest dose studied, so the risk is at the top of the range.

The evidence does not give a separate weight-gain rate for 600 mg. What it shows is that the pivotal trials used doses from 150 to 600 mg, with 600 mg as the ceiling [1]. The fibromyalgia trials tested 300, 450, and 600 mg, and the higher doses produced better pain relief but also more side effects [2]. Weight gain is listed among the common adverse effects, and the 2025 review notes it as a reason people stop the drug [4].

The dose-response pattern is consistent across the studies: more drug, more effect, more harm. The trials that used 600 mg reported it as tolerable but with dizziness and weight gain [1]. A pooled analysis of pain trials included a 600 mg arm and found the adverse event profile similar to lower doses, though peripheral edema was somewhat more common in people taking other pain drugs alongside [3]. That is the closest the evidence gets to a 600 mg-specific safety readout.

What the evidence does not include is a head-to-head weight-gain comparison of 600 mg versus 150 or 300 mg in the same trial. The rates are buried in the overall adverse event counts, not broken out by dose. So the honest answer is that 600 mg sits at the top of the studied range, and weight gain is a known dose-related effect of the drug class, but no retrieved study gives you the exact percentage at that dose.

My call: weight gain is more likely at 600 mg than at lower doses, but the evidence does not quantify the difference. If you are tapering, expect the weight-gain pressure to ease as the dose drops, though the withdrawal risks mean you should do it slowly. Confidence: moderate.