Gabapentin Dosage Calculator
Calculate gabapentin dosage for postherpetic neuralgia, epilepsy, anxiety, restless leg syndrome, and sleep. Find starting dose, titration schedule, and maintenance range with renal adjustment.
About This Calculator
Our Gabapentin Dosage Calculator helps patients, caregivers, and healthcare professionals determine the appropriate starting dose, titration schedule, and maintenance range for gabapentin based on the specific indication and patient characteristics. Whether you are being treated for postherpetic neuralgia (nerve pain after shingles), epilepsy (partial onset seizures), anxiety disorders, restless leg syndrome, or sleep disturbances, this tool provides evidence-based dosing guidance aligned with FDA-approved labeling and clinical practice guidelines.
The calculator uses dosing protocols from the FDA-approved prescribing information and the Drugs.com clinical database. For adults, dosing varies by indication: postherpetic neuralgia follows a 3-day titration (300 mg on day 1, 600 mg on day 2, then 900 mg/day in 3 divided doses), while epilepsy starts at 900 mg/day in 3 divided doses. For pediatric patients aged 3-12 years, weight-based dosing applies: 10-15 mg/kg/day starting dose, with age-specific maintenance targets (40 mg/kg/day for ages 3-4, 25-35 mg/kg/day for ages 5-12). The calculator also incorporates renal dose adjustment based on creatinine clearance (CrCl), since gabapentin is primarily excreted by the kidneys.
Important Medical Disclaimer
This calculator provides informational dosing estimates based on published guidelines. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider before starting, stopping, or changing any medication. Dosage adjustments should be made by a qualified medical professional who is familiar with your complete medical history.
Frequently Asked Questions
What is gabapentin used for?
Gabapentin is used for postherpetic neuralgia (nerve pain after shingles), epilepsy (partial seizures), and off-label for anxiety, restless leg syndrome, sleep disorders, fibromyalgia, and chronic pain. It works by inhibiting excitatory neurotransmitters in the brain.
What is the starting dose of gabapentin for adults?
The starting dose depends on the indication. For postherpetic neuralgia, start at 300 mg once on day 1, 300 mg twice on day 2, then 300 mg three times on day 3. For epilepsy, start at 300 mg three times daily (900 mg/day). For sleep or anxiety, start at 300 mg once daily and increase gradually.
What is the maximum dose of gabapentin?
For postherpetic neuralgia, the maximum dose is 1800 mg/day. For epilepsy, doses up to 3600 mg/day have been used. For restless leg syndrome and sleep, the maximum is 600 mg/day. Pediatric maximum is 50 mg/kg/day. Always consult a doctor before exceeding recommended doses.
How should gabapentin be taken?
Gabapentin can be taken with or without food. For postherpetic neuralgia and epilepsy, it is usually taken 3 times a day with doses no more than 12 hours apart. For restless leg syndrome, take 600 mg once daily with food at about 5 PM. For sleep, take it before bedtime. Swallow capsules whole with water.
Does gabapentin need renal dose adjustment?
Yes, gabapentin is primarily excreted by the kidneys and requires dose adjustment in renal impairment. For CrCl 30-59 mL/min, reduce to 400-1400 mg/day. For CrCl 15-29 mL/min, reduce to 200-700 mg/day. For CrCl below 15 mL/min, reduce to 100-300 mg/day. Always consult a nephrologist for dosing guidance.
What is the gabapentin dosage for children?
For children aged 3-12 years with epilepsy, the starting dose is 10-15 mg/kg/day divided into 3 doses. The maintenance dose for ages 3-4 is 40 mg/kg/day, and for ages 5-12 is 25-35 mg/kg/day. The maximum dose is 50 mg/kg/day. Gabapentin is not typically recommended for children under 3 years.
Is gabapentin a controlled substance?
Gabapentin is not classified as a narcotic or controlled substance at the federal level in the US, though some states have reclassified it. It works differently from GABA despite its name. It does not cause dependence on its own, but may be misused with other drugs. Always use under medical supervision.
What are the common side effects of gabapentin?
Common side effects include drowsiness, dizziness, memory loss, loss of motor control, and double vision. The most common side effect is drowsiness. Serious side effects include respiratory depression (especially with opioids or alcohol), suicidal thoughts, and severe allergic reactions. Seek medical attention for any serious side effects.