... literature in Gabapentin says its half life is 5-7 hours..so does that mean that half the medication is out of your system in that amount of time? So it would be completely out by 14 hours? I'm taking a dose just at morning and night and trying to figure out if 12 hours is too far to space it apart. Thanks
This question has also been asked and answered here: What is the half-life of a drug?
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.
The half life is how long it takes for half the drug to be out of your body. Five times that is how long it takes to be totally gone. For example if you took 200 mg. In five hrs there would be 100 left. At the end of another 5 hrs there would be 50 left, etc. Therefore it would take 25 hrs. To be totally gone.
See Also: Drug Half Life Explained
- Gabapentin Information for Consumers
- Gabapentin Information for Healthcare Professionals (includes dosage details)
- Side Effects of Gabapentin (detailed)
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