A fixed-dose combination (FDC) of Gabapentin, a gamma-aminobutyric acid (GABA) analogue anticonvulsant, and Methylcobalamin, the active form of Vitamin B12. This combination is primarily used for the management of neuropathic pain, particularly diabetic peripheral neuropathy, by targeting both the aberrant neuronal signaling and the underlying nerve damage or metabolic deficiency. Gabapentin modulates calcium channels to reduce excitatory neurotransmitter release, while Methylcobalamin promotes nerve regeneration and myelin synthesis.
Adult: Neuropathic Pain: Typically 1 tablet (Gabapentin 300mg + Methylcobalamin 500mcg) three times daily (TDS). Gabapentin dose must be titrated: Start with 300mg once daily, increase to 300mg BD on day 2, then 300mg TDS from day 3 onwards. Maximum Gabapentin dose: 3600 mg/day in divided doses.
Note: Take with or without food. Swallow whole with a glass of water. Do not crush or chew. Maintain consistent timing of doses. If a dose is missed, take it as soon as remembered unless it's close to the next dose. Do not double dose.
Gabapentin binds to the α2δ-1 subunit of voltage-gated calcium channels in the central nervous system, reducing the influx of calcium and subsequent release of excitatory neurotransmitters (e.g., glutamate, substance P). This dampens aberrant neuronal excitability and signal transduction in neuropathic pain pathways. Methylcobalamin acts as a cofactor for methionine synthase, essential for myelin synthesis and nerve regeneration. It also may promote nerve growth factor synthesis and inhibit abnormal nociceptive signaling.
Pregnancy: Gabapentin: Pregnancy Category C (US FDA). Limited human data; potential risk. Use only if benefit outweighs risk. Methylcobalamin: Category A (considered safe). In combination, use is not recommended unless clearly needed. Register with pregnancy registry if used.
Driving: ADVISE NOT TO DRIVE or operate heavy machinery, especially during initial titration and dose adjustments, due to dizziness and somnolence. Effects may be potentiated by alcohol.
| Opioids (e.g., Morphine, Codeine) | Potentiates CNS depression (sedation, respiratory depression, death). | Major |
| Alcohol | Increased CNS depression (drowsiness, dizziness). | Major |
| Antacids (Aluminum, Magnesium hydroxide) | Reduces Gabapentin bioavailability by up to 20%. Administer Gabapentin at least 2 hours after antacid. | Moderate |
| CNS Depressants (Benzodiazepines, Barbiturates) | Additive sedation and dizziness. | Moderate |
| Metformin, Proton Pump Inhibitors (long-term) | May reduce Methylcobalamin absorption, potentially counteracting its benefit in the FDC. | Moderate |
Same composition (Gabapentin (300mg) + Methylcobalamin (500mcg)), different brands: