Can gabapentin cause difficulty walking or muscle weakness?

Gabapentin and Movement/Muscle Problems

Yes, gabapentin can cause difficulty walking and various muscle problems, including lack of coordination (ataxia), dizziness, abnormal gait, tremor, and in rare cases, severe myopathy or rhabdomyolysis.

Common Movement-Related Side Effects

The FDA-approved labeling clearly identifies several motor and coordination problems as common adverse effects 1:

• Ataxia (lack of coordination) occurs in 13% of epilepsy patients on gabapentin versus 6% on placebo 1
• Dizziness affects 28% of postherpetic neuralgia patients versus 8% on placebo 1
• Abnormal gait occurs in 2% of patients 1
• Incoordination affects 2% of patients 1
• Tremor occurs in 7% of epilepsy patients versus 3% on placebo 1

The FDA label explicitly warns that "gabapentin tablets can slow your thinking and motor skills" and advises patients not to drive or operate heavy machinery until they know how the medication affects them 1.

Dose-Response Relationship

The risk of falls and fractures increases significantly with higher doses 2:

• At doses ≥2,400 mg/day, the relative risk of falls or fractures is 1.90 (nearly double the baseline risk) 2
• Even at therapeutic doses of 600-2,399 mg/day, there is elevated risk 2
• A large Veterans Affairs study of 571,718 patients found gabapentin increased falls/fractures by 35% overall (incidence rate ratio 1.35) 2

Serious Muscle Complications (Rare but Important)

While uncommon, gabapentin can cause severe muscle problems that require immediate discontinuation:

Rhabdomyolysis and Severe Myopathy

A case report documented an 85-year-old diabetic woman who developed severe myopathy with rhabdomyolysis after just one day of gabapentin 150 mg three times daily 3. Her creatine kinase rose to 3,095 U/L and myoglobin to 17,000 mg/dL, with acute renal failure 3. Complete recovery occurred within 10 days of gabapentin withdrawal 3.

Myokymia (Continuous Muscle Rippling)

A 2021 case report described a patient taking 9,600 mg daily who developed myokymia (involuntary muscle rippling), myoclonus, and painful muscle spasms in all extremities 4. Symptoms improved within 3 days of stopping gabapentin 4.

Gait Disturbance at Low Doses

Even low doses can cause problems, particularly with drug interactions. A case report showed a patient developed lower extremity weakness and gait disturbance on just 200 mg of gabapentin when combined with sodium valproate and flunitrazepam 5. Halving the dose resolved the gait disturbance while maintaining pain relief 5.

Special Populations at Higher Risk

Patients with Myasthenia Gravis

Gabapentin should be used with extreme caution or avoided in myasthenia gravis 6. A case report and animal study demonstrated that gabapentin can unmask or worsen myasthenia gravis, causing ocular, facial, and masticatory weakness 6. In experimental autoimmune myasthenia gravis rats, gabapentin induced abnormal decremental responses on nerve stimulation testing 6.

Elderly Patients

The FDA label notes that "the incidence of adverse reactions increased slightly with increasing age" 1. Given that falls and fractures have more serious consequences in older adults, particular vigilance is warranted in this population 2.

Patients with Comorbidities

While patients with hepatitis C, HIV, or alcohol use disorder had elevated baseline incidence of falls regardless of gabapentin exposure, the medication still contributed additional risk in most other subgroups 2.

Clinical Monitoring Recommendations

Monitor patients specifically for:

• Dizziness and coordination problems, especially during dose titration 1
• New onset weakness or difficulty walking 5, 3
• Muscle pain or spasms that could indicate myopathy 4, 3
• Falls, particularly in elderly patients or those on doses ≥600 mg/day 2

Key pitfall to avoid: The FDA label warns that gabapentin can cause somnolence and dizziness, which "could increase the occurrence of accidental injury, including falls" 1. This risk is often underestimated in clinical practice, but the large VA study confirms it is substantial and dose-dependent 2.

Practical Management

If gait disturbance or muscle problems develop:

1. Consider immediate discontinuation if severe myopathy is suspected (muscle pain with weakness) 3
2. Reduce the dose if symptoms are mild—even halving the dose may resolve gait problems while maintaining efficacy 5
3. Review drug interactions, particularly with other CNS depressants like benzodiazepines or valproate 5
4. Do not abruptly stop without medical supervision, as this can precipitate seizures in epilepsy patients 1

The evidence from both FDA labeling and clinical studies consistently demonstrates that gabapentin carries significant risk for movement disorders and muscle problems, with clear dose-dependent effects that clinicians must actively monitor and manage 1, 2.