Half life of Gabapentin? Can someone tell me what exactly the half life of a medicine means? The?

The half-life of gabapentin is approximately 5 to 7 hours in healthy adults. The half-life in children less than 12 years is reported as 4.7 hours. Half-life can vary greatly depending on renal function and other factors. In people with kidney failure, the half-life can be as long as 132 hours.

Half-life should not be confused with the duration of effect. Gabapentin requires three times daily administration because of its short duration of effect. Gabapentin enacarbil (brand name Horizant) only requires once-daily dosing because it has been formulated to have a longer duration of effect.

What is half-life?

The half-life of a drug is an estimate of the time it takes for the concentration or amount in the body of that drug to be reduced by exactly one half (50%).

After four to five half-lives, 97% of a drug has cleared from the body, and the drug is no longer considered to be having an effect, although, for most drugs, actual noticeable effects would have worn off well before then. This means it will take approximately 25 to 35 hours for one dose of gabapentin to be cleared from the body.

In reality, the half-life of gabapentin varies from person to person, and even sometimes within the same person. The half-life of gabapentin can be affected by the following factors:

• Age (very young/very old)
• Kidney disease
• Interacting medications
• Pre-existing conditions.

See our article Drug Half-life Explained for more general information about half-lives.