gabapentin NEURONTIN
Class: AED/Alpha-2-delta LigandFDA Indications: Partial Seizures With Or Without Secondary Generalization (adjunctive), Postherpetic Neuralgia
Off-Label Use: Neuropathic Pain, Anxiety, Fibromyalgia, Bipolar Disorder, Alcohol Withdrawal, Alcohol Dependence, Brachioradial Pruritus, Chronic Cough, Diabetic Neuropathy, Hot Flashes, Restless Leg Syndrome, Postoperative Pain (adjunct), Social Anxiety, Uremic Pruritus, Treatment Resistant Bipolar Disorder, Lewy Body Dementia
Prescribing
Forms: 100, 300, 400mg capsule; 600, 800mg tablet; 250 mg/5 mL po solnDose Range: 900-3600 mg/day
Starting: start at 300 mg q.h.s., increasing gradually to 300 mg t.i.d., then higher as tolerated
Precautions
Serious Side Effects: Can exacerbate myoclonus, but the effect is mild and does not require discontinuance of the drugSide Effects: headache, ataxia, tremor, diarrhea, peripheral edema, nystagmus, diplopia, dizziness (17-28%), drowsiness (18-21%), fatigue (11%)
Pharmacodynamics
1° MOA: Binds to the α2δ subunit of presynaptic N and P/Q VGCCs, block the release of excitatory neurotransmitters such as glutamate when neurotransmission is excessivePharmacokinetics
t½: 6 (5-8)° TMAX: 2-3°Substrate of: Renally cleared
Inhibits: ∅ ; Induces: ∅
Active Metabolites: ∅
DDIs
- - caution when prescribing with other CNS depressants; can cause respiratory depression when combined with opioids
- - concomitant treatment with opioids is associated with a substantial increase in the risk of opioid-related death
- - Maalox ↓'s bioavailability by 20%, so have patient take Neurontin at least 2 hours after Maalox
- - ↓'s hydrocodone levels by up to 20% for unknown reasons
Misc
- - surprisingly has no direct GABA-mimetic activity
- - relatively mild side effect profile besides sedation/fatigue
- - few DDIs!
- - ↑'s slow-wave δ sleep
- - apparently no potential for overdose: 1 patient took 49 grams in overdose with no serious sequelae
Special Populations
Category C—Limited Human Data — Animal Data Suggest Risk
RID 1.3-3.8%; Limited Human Data—Probably Compatible
No dosage adjustment necessary
CrCl ≥60 mL/min: 300-1,200 mg tid
CrCl >15-59 mL/min: 200-700 mg tid
CrCl 15 mL/min:100-300 mg qd
CrCl <15 mL/min: ↓ dose in proportion to CrCl based on dose for CrCl of 15mL/min
ESRD requires hemodialysis
Not hepatically metabolized ∴ no dose adjustments required
References
Stahl's Essential Psychopharmacology 4th EdApplied Clinical Pharmacokinetics And Pharmacodynamics Of Psychopharmacological Agents
Foye's Principles Of Medicinal Chemistry
Drugs In Pregnancy And Lactation 11th Ed
Gabapentin, Opioids, And The Risk Of Opioid-related Death: A Population-based Nested Case–control Study
