What is the initial dosage of gabapentin (Neurontin) to start therapy?

From the Guidelines

The recommended starting dosage of gabapentin is 100-300 mg at bedtime or 100-300 mg three times daily, with a gradual increase by 100-300 mg every 1-7 days as tolerated. This dosage is based on the study published in the Mayo Clinic Proceedings 1, which provides guidelines for the pharmacological management of neuropathic pain. The study suggests that the dosage of gabapentin should be increased gradually to minimize side effects and to allow the patient to tolerate the medication.

The dosage of gabapentin may need to be adjusted based on the patient's response and tolerability, with a maximum dosage of 3600 mg daily divided into three doses 1. It is also important to consider the patient's renal function when adjusting the dosage, as gabapentin is excreted by the kidneys. For elderly patients or those with kidney impairment, lower starting doses and slower titration are recommended.

Some key points to consider when starting gabapentin include:

• Starting with a low dose and gradually increasing as needed and tolerated
• Taking the medication with food to improve absorption and reduce stomach upset
• Maintaining consistent blood levels by taking the medication at evenly spaced intervals throughout the day
• Gradually reducing the dosage under medical supervision if it needs to be stopped, to avoid withdrawal symptoms.

It's worth noting that the study published in the Journal of the National Comprehensive Cancer Network 1 also supports the use of gabapentin for the management of neuropathic pain, and provides similar guidelines for the starting dosage and titration of the medication. However, the study published in the Mayo Clinic Proceedings 1 is more comprehensive and provides more detailed guidelines for the management of neuropathic pain.

From the FDA Drug Label

In adults with postherpetic neuralgia, gabapentin may be initiated on Day 1 as a single 300 mg dose, on Day 2 as 600 mg/day (300 mg two times a day), and on Day 3 as 900 mg/day (300 mg three times a day). The starting dose is 300 mg three times a day. The starting dose range is 10 mg/kg/day to 15 mg/kg/day, given in three divided doses

The recommended starting dosage of gabapentin is:

• 300 mg on Day 1 for postherpetic neuralgia
• 300 mg three times a day for epilepsy with partial onset seizures in patients 12 years of age and above
• 10 mg/kg/day to 15 mg/kg/day in three divided doses for pediatric patients age 3 to 11 years 2

From the Research

Dosage of Gabapentin

• The dosage of gabapentin to start with is not explicitly stated in the provided studies, but it is mentioned that most studies used oral gabapentin or gabapentin encarbil at doses of 1200 mg or more daily in different neuropathic pain conditions 3.
• Gabapentin at doses of 1800 mg to 3600 mg daily (1200 mg to 3600 mg gabapentin encarbil) can provide good levels of pain relief to some people with postherpetic neuralgia and peripheral diabetic neuropathy 3.
• There is no firm evidence to answer the important pragmatic questions about which patients should have which drug, and in which order the drugs should be used, including the dosage of gabapentin 4.

Efficacy and Safety of Gabapentin

• Gabapentin is effective in treating neuropathic pain, particularly in postherpetic neuralgia and painful diabetic neuropathy, with a number needed to treat for an additional beneficial outcome (NNT) of 4 to 10 3, 4.
• Gabapentin is associated with a high risk of adverse events, including dizziness, somnolence, peripheral oedema, and gait disturbance, and a significant number of participants experience at least one adverse event 3, 5.
• The safety aspects of gabapentin are important to consider, particularly in non-epilepsy indications such as neuropathic pain and psychiatry, where it is increasingly used 5.

Comparison with Other Antiepileptic Drugs

• Gabapentin and pregabalin are the only antiepileptic drugs with reasonably good evidence for efficacy in neuropathic pain, particularly in painful diabetic neuropathy and postherpetic neuralgia 4.
• Pregabalin may afford better tolerability and lower pill burden compared to gabapentin, although there is no significant difference in meaningful pain reduction between the two drugs 6.