You should check with your doctor immediately if any of these side effects occur when taking gabapentin:

More common

Clumsiness or unsteadiness

continuous, uncontrolled, back-and-forth, or rolling eye movements

More common in children

Aggressive behavior or other behavior problems

anxiety

concentration problems and change in school performance

crying

depression

false sense of well-being

hyperactivity or increase in body movements

rapidly changing moods

reacting too quickly, too emotional, or overreacting

restlessness

suspiciousness or distrust

  • pain
  • sleep

Less common

Black, tarry stools

chest pain

chills

cough

depression, irritability, or other mood or mental changes

fever

loss of memory

pain or swelling in the arms or legs

painful or difficult urination

shortness of breath

sore throat

sores, ulcers, or white spots on the lips or in the mouth

swollen glands

unusual bleeding or bruising

unusual tiredness or weakness

Incidence not known

Abdominal or stomach pain

blistering, peeling, or loosening of the skin

clay-colored stools

coma

confusion

convulsions

dark urine

decreased urine output

diarrhea

dizziness

fast or irregular heartbeat

headache

increased thirst

itching or skin rash

joint pain

large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs

loss of appetite

muscle ache or pain

nausea

red skin lesions, often with a purple center

red, irritated eyes

unpleasant breath odor

vomiting of blood

yellow eyes or skin