Are severe leg cramps a side effect of Neurontin?

Another cause of muscle cramping and pain could be low potassium, and there are many many drugs that can cause this, so you may want to try eating some high in potassium foods while you are waiting to get in with your doctor. Some foods high in potassium inclue bananas, potatoes, rice, orange juice, and there are a good bit more that you can look up. Low potassium can cause the pain described, hospitilization as well as death if untreated, so it is something to take a bit seriously, and is usually the last thing people thing of.
Hope it helps,
Amy

Yes, unfortunately the severe side effects of Neurontin (Gabapentin) is: numbness of an arm or leg; one-sided weakness; swelling of the hands, legs, or feet.

Read more: https://www.drugs.com/sfx/neurontin-side-effects.html#ixzz0usuKJJrB

In about 8.3% people the swelling or fluid retention in the legs, feet, arms, or hands, has been reported which could lead to cramps.

You need to seek medical attention, please talk to your doctor/pharmacist who prescribed the med., hope the info helps, with best wishes!