Neurontin (Gabapentin)

Neurontin (gabapentin) is used to treat several neurological conditions that involve abnormal nerve signaling.

• Partial seizures: reduces seizure frequency in patients with focal epilepsy.
• Postherpetic neuralgia: alleviates persistent pain following shingles infection.
• Neuropathic pain: diminishes pain intensity in diabetic peripheral neuropathy and other chronic nerve pain states.
• Restless legs syndrome: lessens uncomfortable sensations and urges to move the legs, improving sleep quality.

• Gabapentin binds selectively to the α2δ subunit of voltage‑gated calcium channels in central nervous system neurons. This binding reduces calcium influx during depolarization, thereby decreasing the release of excitatory neurotransmitters such as glutamate, norepinephrine, and substance P. The overall effect dampens neuronal hyper‑excitability, which underlies its anticonvulsant and analgesic properties.

Gabapentin may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Dizziness: sensation of light‑headedness or unsteadiness.
• Somnolence: increased sleepiness or fatigue.
• Peripheral edema: swelling of the lower extremities.
• Weight gain: gradual increase in body weight.
• Visual disturbances: blurred vision or double vision.
• Dry mouth: reduced salivation.

Serious or Rare Side Effects

• Suicidal ideation: emergence of thoughts of self‑harm.
• Severe allergic reactions: including Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Respiratory depression: especially when combined with other CNS depressants.
• Angioedema: rapid swelling of face, lips, or throat.
• Blood dyscrasias: such as agranulocytosis or thrombocytopenia.
• Rhabdomyolysis: muscle breakdown leading to elevated CK levels.

Before initiating gabapentin therapy, several safety considerations should be reviewed.

• Renal impairment: dose adjustment may be required in patients with reduced kidney function.
• Central nervous system depression: avoid activities requiring alertness until individual response is known.
• Pregnancy: safety category is unknown; weigh potential benefits against risks.
• Suicidality risk: monitor patients for mood changes or emergent suicidal thoughts.
• Abrupt discontinuation: taper gradually to reduce risk of withdrawal seizures.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, and protect from moisture.

Gabapentin interacts with several drug classes; awareness helps prevent adverse outcomes.

Major Interactions (Avoid)

• Antacids containing aluminum or magnesium: reduce gabapentin absorption; separate dosing by at least 2 hours.
• CNS depressants (e.g., benzodiazepines, barbiturates): may cause excessive sedation or respiratory depression.
• Opioids: combined use increases risk of profound CNS depression and respiratory compromise.
• Alcohol: potentiates sedative effects and impairs coordination.

Moderate Interactions (Monitor Closely)

• NSAIDs: concurrent use may heighten risk of renal impairment.
• ACE inhibitors or ARBs: monitor renal function and electrolytes.
• Diuretics: may exacerbate peripheral edema.
• Carbamazepine: can lower gabapentin plasma concentrations, reducing efficacy.