Magnesium Glycinate and Gabapentin Interaction
There is a clinically significant interaction between magnesium-containing compounds and gabapentin that reduces gabapentin absorption and effectiveness, requiring separation of administration times by at least 2 hours. 1
Mechanism of Interaction
- Magnesium oxide and other magnesium-containing compounds, including magnesium glycinate, interact with gabapentin by reducing its bioavailability through interference with gastrointestinal absorption 1
- This interaction occurs at the level of the gut, where magnesium can bind to or interfere with gabapentin's absorption mechanism 1
- Gabapentin is not metabolized and is eliminated unchanged by the kidneys, meaning the interaction is purely absorption-based rather than metabolic 2
Clinical Management Strategy
Separate administration of magnesium glycinate and gabapentin by at least 2 hours to avoid reduced gabapentin efficacy. 1
- Administer gabapentin first, then wait 2 hours before taking magnesium glycinate, or vice versa 1
- This separation allows gabapentin to be absorbed before magnesium is present in the gastrointestinal tract 1
- Monitor for reduced gabapentin effectiveness if the patient reports taking these medications together, as this may manifest as breakthrough pain or seizures depending on the indication 1
Additional Safety Considerations
- Gabapentin commonly causes somnolence, dizziness, and mental clouding, particularly in older adults 3, 4
- The American Geriatrics Society recommends avoiding concurrent use of opioids with gabapentin due to increased risk of respiratory depression and overdose 5
- Avoid combining gabapentin with benzodiazepines, as this drug-drug interaction can lead to substantial harm including respiratory depression 5
- When using three or more CNS-active agents (including gabapentin, antidepressants, antipsychotics, benzodiazepines, or opioids), there is increased fall risk that requires careful monitoring 5
Dosing Adjustments for Special Populations
- In patients with renal impairment, start gabapentin at the lowest doses (100-200 mg/day) and adjust based on creatinine clearance 3, 4
- For elderly patients, initiate therapy at 100-300 mg at bedtime or 100-300 mg three times daily, with slower titration to minimize adverse effects 4
- Doses in clinical practice are often lower than the 3600 mg/day used in trials, which may lead to suboptimal efficacy 3