Gabapentin drug interactions

List of drug interactions
Phenytoin Carbamazepine Valproic Acid Phenobarbital Naproxen Hydrocodone Morphine Cimetidine Oral Contraceptive Antacid (Maalox®) Effect of Probenecid

Phenytoin
In a single (400 mg) and multiple dose (400 mg TID) study of Neurontin in epileptic patients (N=8) maintained on phenytoin monotherapy for at least 2 months, gabapentin had no effect on the steady-state trough plasma concentrations of phenytoin and phenytoin had no effect on gabapentin pharmacokinetics.Return to top

Carbamazepine
Steady-state trough plasma carbamazepine and carbamazepine 10, 11 epoxide concentrations were not affected by concomitant gabapentin (400 mg TID; N=12) administration. Likewise, gabapentin pharmacokinetics were unaltered by carbamazepine administration. Return to top

Valproic Acid
The mean steady-state trough serum valproic acid concentrations prior to and during concomitant gabapentin administration (400 mg TID; N=17) were not different and neither were gabapentin pharmacokinetic parameters affected by valproic acid.Return to top

Phenobarbital
Estimates of steady-state pharmacokinetic parameters for phenobarbital or gabapentin (300 mg TID; N=12) are identical whether the drugs are administered alone or together.Return to top

Naproxen
Coadministration (N=18) of naproxen sodium capsules (250 mg) with Neurontin (125 mg) appears to increase the amount of gabapentin absorbed by 12% to 15%. Gabapentin had no effect on naproxen pharmacokinetic parameters. These doses are lower than the therapeutic doses for both drugs. The magnitude of interaction within the recommended dose ranges of either drug is not known.Return to top

Hydrocodone
Coadministration of Neurontin (125 to 500 mg; N=48) decreases hydrocodone (10 mg; N=50) Cmax and AUC values in a dose-dependent manner relative to administration of hydrocodone alone; Cmax and AUC values are 3% to 4% lower, respectively, after administration of 125 mg Neurontin and 21% to 22% lower, respectively, after administration of 500 mg Neurontin. The mechanism for this interaction is unknown. Hydrocodone increases gabapentin AUC values by 14%. The magnitude of interaction at other doses is not known.Return to top

Morphine
A literature article reported that when a 60-mg controlled-release morphine capsule was administered 2 hours prior to a 600-mg Neurontin capsule (N=12), mean gabapentin AUC increased by 44% compared to gabapentin administered without morphine. Morphine pharmacokinetic parameter values were not affected by administration of Neurontin 2 hours after morphine. The magnitude of interaction at other doses is not known.Return to top

Cimetidine
In the presence of cimetidine at 300 mg QID (N=12) the mean apparent oral clearance of gabapentin fell by 14% and creatinine clearance fell by 10%. Thus cimetidine appeared to alter the renal excretion of both gabapentin and creatinine, an endogenous marker of renal function. This small decrease in excretion of gabapentin by cimetidine is not expected to be of clinical importance. The effect of gabapentin on cimetidine was not evaluated. Return to top

Oral Contraceptive
Based on AUC and half-life, multiple-dose pharmacokinetic profiles of norethindrone and ethinyl estradiol following administration of tablets containing 2.5 mg of norethindrone acetate and 50 mcg of ethinyl estradiol were similar with and without coadministration of gabapentin (400 mg TID; N=13). The Cmax of norethindrone was 13% higher when it was coadministered with gabapentin; this interaction is not expected to be of clinical importance.Return to top

Antacid (Maalox®)
Maalox reduced the bioavailability of gabapentin (N=16) by about 20%. This decrease in bioavailability was about 5% when gabapentin was administered 2 hours after Maalox. It is recommended that gabapentin be taken at least 2 hours following Maalox administration.Return to top

Effect of Probenecid
Probenecid is a blocker of renal tubular secretion. Gabapentin pharmacokinetic parameters without and with probenecid were comparable. This indicates that gabapentin does not undergo renal tubular secretion by the pathway that is blocked by probenecid.Return to top

Major Interactions
Darvon, Darvon-N, GHB, levomethadyl acetate, Orlaam, PP-Cap, propoxyphene, propoxyphene hydrochloride, propoxyphene napsylate, sodium oxybate, Xyrem

Moderate Interactions
40 Winks, Abilify, Abilify Discmelt, acetylcarbromal, Actiq, Adapin, Adgan, AHist, Akineton HCl, alcohol, alcohol, ethyl, Aler-Dryl, Aler-Tab, Alfenta, alfentanil, All Day Allergy, Aller-Chlor, Allergia-C, Allerhist-1, Allermax, Alphagan, Alphagan P, alprazolam, alprazolam extended release, Altaryl, Ambien, Ambien CR, amitriptyline, amobarbital, amoxapine, Amrix, Amytal Sodium, Anafranil, Anergan 50, Antiflex, Antinaus 50, APO-Go, APO-Go Pen, Apokyn, apomorphine, apraclonidine ophthalmic, Aquachloral Supprettes, aripiprazole, Artane, Asendin, Astramorph PF, Atarax, Aventyl HCl, Avinza, azatadine, B-Vex, baclofen, Banaril, Banflex, Banophen, Beldin, Belix, Ben-Tann, Benadryl, Benadryl Allergy, Benadryl Child Dye Free, Benadryl Childrens Allergy Fastmelt, Benadryl DF, Benadryl Dye Free Allergy, Benadryl Ultratab, Benahist-10, Benahist-50, Benoject-50, Benzacot, benztropine, Bidhist, biperiden, brimonidine ophthalmic, Bromaphen, bromocriptine, bromodiphenhydramine, brompheniramine, brompheniramine extended release, BroveX, BroveX CT, Buprenex, buprenorphine, Busodium, BuSpar, BuSpar Dividose, busPIRone, butabarbital, butalbital, Butisol Sodium, butorphanol, butorphanol nasal, Bydramine, C.P.M., Calm-Aid, Carbacot, carbamazepine, carbamazepine extended release, Carbatrol, carbetapentane, carbinoxamine, carbinoxamine extended release, Carbinoxamine PD, Carboxine, carisoprodol, Catapres, Catapres-TTS-1, Catapres-TTS-2, Catapres-TTS-3, Celexa, Cerebyx, Cesamet, cetirizine, Chem Mart Tramadol, Chlo-Amine, Chlor-Al Rel, Chlor-Mal, Chlor-Phen, Chlor-Phenit, Chlor-Trimeton, Chlor-Trimeton Allergy SR, chloral hydrate, chlordiazepoxide, chlormezanone, Chlorphen, chlorphenesin, chlorpheniramine, Chlorpheniramine (Allergy), chlorpheniramine 24 hour extended release, chlorpheniramine extended release, chlorproMAZINE, chlorproMAZINE extended release, ChlorTan, chlorzoxazone, citalopram, clemastine, clomiPRAMINE, clonidine, clonidine topical, Clopine, clorazepate, clorazepate extended release, clozapine, Clozapine Synthon, Clozaril, codeine, codeine phosphate, codeine sulfate, Codimal A, Cogentin, colesevelam, Compazine, Compazine Spansule, Compoz Nighttime Sleep Aid, Compro, Comtan, Contac 12 Hour Allergy, Cophene B, Cordron NR, cyclobenzaprine, cyclobenzaprine extended release, Cylert, Cymbalta, cyproheptadine, Dailyhist-1, Dalgan, Dalmane, Dantrium, Dantrium Intravenous, dantrolene, Dazidox, Dehydrated Alcohol, Demerol HCl, Denzapine, DepoDur, desipramine, desvenlafaxine, Desyrel, Desyrel Dividose, dexbrompheniramine, dexmedetomidine, dezocine, Di-Phen, dihydrocodeine, Dilantin, Dilantin Infatabs, Dilantin Kapseals, Dilantin-125, Dilaudid, Dilaudid-5, Dilaudid-HP, Dimetane, Dimetane Extentab, Dimetapp Allergy, Dimetapp Allergy Liquigel, Diphedryl, Diphen, Diphen AF, Diphen Cough, Diphenadryl, Diphendryl, Diphenhist, diphenhydrAMINE, diphenhydrAMINE citrate, diphenhydrAMINE tannate, Diphenmax, Diphenydramine Quick Melt, Diphenyl, Diphenylin, Diprivan, Diskets, Dolophine, Doloral, Doloral Sirop, Doral, doxepin, doxepin topical, doxylamine, DPH, Dromadol SR, Dromadol XL, dronabinol, duloxetine, Duraclon, Duragesic, Duragesic-100, Duragesic-12, Duragesic-25, Duragesic-50, Duragesic-75, Duramorph PF, Dytan, Dytuss, Ed Chlor-Tan, Ed ChlorPed, Effexor, Effexor XR, Efidac-24 Chlorpheniramine, Elavil, Endep, Endocodone, entacapone, Epitol, Equanil, Equetro, escitalopram, Eskalith, Eskalith-CR, estazolam, eszopiclone, ETH-Oxydose, ethanol, Ethyl Alcohol, Eze D.S., FazaClo, fentanyl, fentanyl topical, Fentora, Fexmid, flavoxate, Flexeril, Flexoject, Flexon, fluoxetine, fluoxetine extended release, fluphenazine, fluphenazine decanoate, fluphenazine enanthate, fluphenazine hydrochloride, flurazepam, fluvoxamine, fluvoxamine extended release, fosphenytoin, Genahist, GenRx Tramadol, Geodon, halazepam, Halcion, Haldol, Haldol Decanoate, haloperidol, haloperidol decanoate, Histaject, Histex CT, Histex I/E, Histex PD, Histex Pd 12, Hydramine, Hydramine Compound, Hydramine Cough Syrup, hydrocodone, Hydromorph Contin, hydromorphone, hydromorphone extended release, Hydrostat IR, hydrOXYzine, hydrOXYzine hydrochloride, hydrOXYzine pamoate, hypericum perforatum, Hyrexin, Hyzine, imipramine, imipramine pamoate, Infumorph, Invega, Ionsys, Iopidine, isocarboxazid, J-Tan, J-Tan PD, Kadian, Kemadrin, Ketalar, ketamine, Larapam SR, Largon, Lariam, Levo-Dromoran, levocetirizine, levorphanol, LEVRIX, Lexapro, Librium, Lioresal, Lioresal Intrathecal, lithium, lithium carbonate, lithium carbonate extended release, lithium citrate, Lithobid, Lithonate, Lithotabs, Lodrane 12 Hour, Lodrane 24, Lodrane XR, loxapine, Loxitane, Loxitane C, Loxitane IM, Ludiomil, Lunesta, Luvox, Luvox CR, Lyrica, M-Eslon, M-Oxy, M. O. S., Maolate, maprotiline, Marinol, Marplan, MB-TAB, mefloquine, Mellaril, Mellaril-S, meperidine, meprobamate, Meridia, mesoridazine, metaxalone, methadone, Methadose, methocarbamol, metoclopramide, midazolam, Miltown, Mio-Rel, Mirapex, mirtazapine, Mitran, Moban, molindone, morphine, morphine 24 hour extended release, morphine extended release, Morphine IR, morphine liposomal, Morphine LP Epidural, morphine preservative-free, Morphine Rapi-Ject, Morphitec, MS, MS Contin, MS/S, MSIR, Myolin, nabilone, nalbuphine, Nardil, Nasahist B, Navane, ND-Stat, nefazodone, Nembutal, Nembutal Sodium, Nervine, Neupro, Nightime Sleepaid, Niravam, Norflex, Norflex Injectable, Norpramin, nortriptyline, Nu-Med, Nubain, Numorphan HCl, Nytol Caplet, Nytol Maximum Strength, olanzapine, olopatadine nasal, OMS, Opana, Opana ER, opium, Opium Deodorized, Optimine, Oramorph SR, Orap, Orfro, Ormazine, orphenadrine, orphenadrine extended release, Orphenate, oxazepam, oxycodone, oxycodone extended release, OxyContin, Oxyfast, OxyIR, oxymorphone, oxymorphone extended release, P-Tann, P-Tex, Palgic, paliperidone, Palladone, Palladone SR, Pamelor, Paraflex, Parafon Forte DSC, Paral, paraldehyde, Pardryl, Paregoric, Parlodel, Parnate, paroxetine, paroxetine extended release, paroxetine mesylate, Patanase, Paxarel, Paxil, Paxil CR, PBZ, PBZ-SR, PediaTan, Pediatex, Pediatex 12, Pediox, Pediox-S, pemoline, Pentazine, pentazocine, pentobarbital, Percolone, pergolide, Periactin, Permax, Permitil, perphenazine, Pexeva, Phenadoz, Phenazine 50, phenelzine, Phenergan, Phenergan Fortis, Phenoject-50, Phenytek, phenytoin, phenytoin extended release, Phenytoin Sodium, Prompt, pimozide, pramipexole, Precedex, pregabalin, Prialt, Pristiq, Pro-Med, prochlorperazine, prochlorperazine extended release, Procot, procyclidine, Prolixin, Prolixin Decanoate, Prolixin Enanthate, Promacot, promazine, promethazine, Promethegan, Prop-A-Tane, propiomazine, propofol, Prorex, Prosom, protriptyline, Prozac, Prozac Weekly, Prudoxin, Q-Dryl, Q-Dryl A/F, QDALL AR, quazepam, Quenalin, quetiapine, quetiapine extended release, Rapiflux, Reglan, Relaxazone, Remeron, Remeron SolTab, remifentanil, Remular, Remular-S, Repreve, Requip, ReQuip Follow on Pack, Requip Starter Kit, ReQuip Starter Pack, Rescudose, Restoril, Rezine, Ridramin, Risperdal, Risperdal Consta, Risperdal M-Tab, risperidone, RMS, Robaxin, Robaxin-750, Rohist, ropinirole, rotigotine, Roxanol, Roxanol 100, Roxanol-T, Roxicodone, Roxicodone Intensol, Sarafem, Scot-Tussin Allergy Relief Formula, secobarbital, Seconal Sodium, Selfemra, Serax, Serentil, Seroquel, Seroquel XR, sertraline, Serzone, sibutramine, Siladryl, Siladryl DAS, Siladyl SA, Silphen Cough, Siltane, Simply Sleep, Sinequan, Skelaxin, Skelex, Sleep Tab II, Sleep Tabs, Sleep-ettes, Sleep-Eze-3, Sleepinal, solotuss, Soma, Sominex, Sominex Maximum Strength Caplet, Somnicaps, Somnote, Sonata, Sparine, St. John's wort, Stadol, Stadol NS, Statex, Stelazine, Strifon Fort, Sublimaze, Subutex, Sufenta, sufentanil, Surmontil, Talwin Lactate, Tanacof-XR, TanaHist-PD, Tasmar, Tavist, Tavist Allergy, Tavist-1, Tegretol, Tegretol XR, Temaril, temazepam, Terry White Chemists Tramadol, thalidomide, Thalomid, Theraflu Thin Strips Multi Symptom, thioridazine, thiothixene, Thorazine, Ticon, Tigan, tizanidine, Tofranil, Tofranil-PM, tolcapone, Total Allergy, traMADOL, traMADOL extended release, Tramahexal, Tramahexal SR, Tramake, Tramake Insts, Tramal, Tramal SR, Tramedo, Trancopal, Tranxene SD, Tranxene T-Tab, tranylcypromine, traZODONE, Triaminic Allergy, Triaminic Thin Strips Cough & Runny Nose, triazolam, trifluoperazine, triflupromazine, Trihexane, trihexyphenidyl, Trilafon, trimeprazine, trimethobenzamide, trimipramine, tripelennamine, Tripohist, triprolidine, triprolidine extended release, Trux-adryl, Tusstat, Twilite, Ultiva, Ultram, Ultram ER, Uni-Tann, Unisom, Unisom Sleepgels Maximum Strength, Uprima, Urispas, V-Gan-25, V-Gan-50, Valu-Dryl, Vanadom, Vanatrip, VaZol, venlafaxine, venlafaxine extended release, Versed, Vistacon, Vistacot, Vistaject-50, Vistaril, Vistaril IM, Vistazine, Vistazine 50, Vivactil, Wal-finate, Welchol, Xanax, Xanax XR, Xyzal, XYZALL, zaleplon, Zamadol, Zamadol 24hr, Zamadol Melt, Zamadol SR, Zanaflex, Zaponex, ziconotide, ziprasidone, Zoloft, zolpidem, zolpidem extended release, Zonalon, Zydol, Zydol SR, Zydol XL, Zymine, Zymine XR, Zyprexa, Zyprexa Zydis, Zyrtec, Zyrtec Hives

Minor Interactions
Acid Relief, Aloh-Gel, Alternagel, Alu-Cap, Alu-Tab, aluminum hydroxide, Amphojel, cimetidine, Concentrated Phillips Milk of Magnesia, Dewees Carminative, Dialume, dihydroxyaluminum sodium carbonate, evening primrose, Evening Primrose Oil, Ex-Lax Milk of Magnesia, felbamate, Felbatol, gingko, gingko biloba, ginkgo, ginkgo biloba, Losospan, Lowsium, Mag-200, Mag-Carb, Mag-Ox 400, magaldrate, MagGel, magnesium carbonate, magnesium hydroxide, magnesium oxide, magnesium trisilicate, Maoson, Mg hydroxide, Mg oxide, Milk of Magnesia, Phillips Milk of Magnesia, Phillips' Cramp-free, Primrose Oil, Ri-Mag, Riopan, Ron Acid, Tagamet, Tagamet HB, Uro-Mag