01 Section
Orange 400 mg is the mid capsule on a Neurontin strip
400 mg daylight card
Orange 400 mg Neurontin capsules are the middle labelled shell, not a starter and not the scored 600 mg or 800 mg tablets. Pfizer's capsule line is 100 mg white, 300 mg yellow, and 400 mg orange. A first week of postherpetic neuralgia often begins at 300 mg and only later lands on 400 mg three times a day.
Cash talk that names 'gabapentin' without the milligrams is useless at the window. Sixty capsules of 400 mg is a twice-daily month if that is the written rhythm; ninety is the coupon-board count many sites publish. Ask the pharmacist to price the count on the script, not the board that happens to be on the screen.
Regular use changes the last visit. The US label tells clinicians to taper over a minimum of one week when the drug is stopped or swapped. People who treat this like a weekend pain tablet and then skip a day after months of three-times dosing are the ones who write to the shelf about rebound pain and, in epilepsy, more seizures.
Half-life of 5 to 7 hours when kidneys work is why three-times-daily dosing exists. A once-daily 400 mg habit copied from a sleep aid is not Neurontin therapy. Peak levels arrive about 2 to 3 hours after a dose in the pediatric PK work; adults follow the same early-afternoon peak if the morning capsule was taken on time.
02 Section
Creatinine clearance writes the daily total
| Creatinine clearance (mL/min) | Total daily range | Example 400 mg pattern |
|---|---|---|
| 60 or higher | 900 to 3600 mg | 400 mg three times daily is listed |
| >30 to 59 | 400 to 1400 mg | 400 mg twice daily is listed |
| >15 to 29 | 200 to 700 mg | 400 mg once daily is listed |
| 15 | 100 to 300 mg | Use 100 mg shells, not 400 mg |
Renal clearance tracks creatinine clearance. The elimination half-life stays in the 5-to-7-hour band when kidneys work and stretches to about 52 hours when creatinine clearance falls below 30 mL/min. Anuric adults sat near 132 hours on nondialysis days in the label study; dialysis cut the apparent half-life to 3.8 hours.
Hepatic impairment studies were never run because the drug is not metabolized. That is a clearance fact, not a license to ignore liver disease for other reasons on the same chart.
Elderly plasma clearance falls with the same creatinine-clearance line. A 400 mg three-times-daily habit copied from a 40-year-old onto an 82-year-old with a creatinine of 1.8 mg/dL is how people arrive unsteady and over-sedated.
Hemodialysis pulls gabapentin off. Anuric adults in the label study had an apparent half-life near 132 hours on nondialysis days and 3.8 hours during dialysis. A supplemental post-dialysis dose is on the table. Skipping that dose because 'the capsule is only 400 mg' is how Monday seizures or Monday pain return after a weekend session.
03 Section
Sixty orange capsules versus the ninety-count board
GoodRx capsule board
400 mg x 90
$103.87 / $17.56Average retail, then coupon print, September 2026.
This page lock
400 mg x 60
Ask for sixtyA twice-daily month at the Bellis 400 mg lock. Not the ninety-count board.
Generic gabapentin 400 mg capsules, sixty count, the Bellis mid-capsule lock, marked September 2026. GoodRx's capsule table lists 400 mg x 90 at $103.87 average retail and $17.56 with a coupon. Ask the window to price sixty if that is the prescribed count. GoodRx stays in this caption. Each link is that pharmacy only. Bellis does not dispense. Prescription required. Taper; do not drop the dose on a webpage.
Fred Meyer, Jewel-Osco, Winn-Dixie, and Albertsons are the four official pharmacy pages on this Copenhagen note. Each href opens that chain only. GoodRx stays in the caption under the compare block, never as a store link.
Published coupon boards often price 400 mg by ninety. This page locks sixty, which is a twice-daily month if that is what was prescribed. If the script says three times daily, say so at the window and have them price ninety or the actual written count.
Brand Neurontin and generic gabapentin are not the same cash line. Strength alone also fails: 100 mg and 300 mg capsules, plus 600 mg and 800 mg tablets, are other NDCs. Horizant and Gralise are other products entirely.
Oral contraceptives were studied with gabapentin 400 mg three times a day. Norethindrone and ethinyl estradiol AUC and half-life stayed similar. A 13 percent rise in norethindrone Cmax was not judged clinically important. That is not a reason to skip a pregnancy plan conversation in epilepsy care.
04 Section
Climbing toward 400 mg three times a day
Adults 12 and older with partial-onset seizures start at 300 mg three times daily on the epilepsy line and may be titrated to 600 mg three times daily. A 400 mg three-times-daily pattern (1200 mg a day) sits in the middle of the renal table for creatinine clearance of 60 mL/min or higher.
Spacing matters more than people admit. The longest gap between doses should not exceed 12 hours. A 400 mg capsule at breakfast and nothing until the next afternoon is not three-times-daily therapy. It is two forgotten doses and a complaint that 'the capsules do nothing.'
Bioavailability falls as the daily total rises: about 60 percent at 900 mg a day, 47 percent at 1200, 34 percent at 2400, 33 percent at 3600, and 27 percent at 4800 mg a day, each given in three divided doses. Pushing past 1800 mg for PHN therefore buys less drug than the milligram arithmetic suggests.
Food only nudges absorption (about a 14 percent rise in AUC and Cmax). Aluminum-magnesium antacids cut mean bioavailability by about 20 percent. The label wants the capsule at least two hours after that antacid. Plasma level monitoring is not required to 'optimize' Neurontin.
05 Section
Breathing slows when an opioid is already on board
Cross-checks before a 400 mg refill
- Opioid or other CNS depressant: monitor breathing and sedation
- Underlying lung disease: same watch, even without an opioid
- Antacid with aluminum or magnesium: separate by at least 2 hours
- Abrupt stop after regular use: taper at least 1 week
Serious, life-threatening, or fatal respiratory depression is in the warnings when gabapentin is combined with CNS depressants, including opioids, or given to someone with underlying respiratory impairment. Morphine, hydrocodone, oxycodone, and buprenorphine are named in the postmarketing file.
Start low and watch if the combination is unavoidable. Somnolence, dizziness, and driving impairment stand on their own even without an opioid. The label tells people not to drive until they know how the capsule hits them.
Suicidal thoughts and behavior are a class warning for antiepileptic drugs. DRESS, anaphylaxis, and angioedema are stop-and-evaluate events. Pediatric patients aged 3 to 12 also have a neuropsychiatric reaction list that parents should hear before the first school-week dose.
Overdose reports include double vision, tremor, slurred speech, drowsiness, and diarrhea. Fatal respiratory depression has occurred with gabapentin overdose alone and with other CNS depressants. A 400 mg capsule is not harmless in a handful.
06 Section
The GABA name is a historical accident
Structurally related to gamma-aminobutyric acid does not mean the capsule works as a GABA-A or GABA-B agonist. DailyMed is blunt: gabapentin has no effect on GABA binding, uptake, or degradation. The designer name stuck. The receptor story did not.
High-affinity binding at the alpha-2-delta subunit of voltage-activated calcium channels is the in-vitro finding the label actually cites. How that binding becomes pain relief or fewer partial seizures is still listed as unknown. That gap is not a reason to invent a GABA-receptor lecture for patients.
Affinity is also lacking at benzodiazepine, mu, delta, and kappa opioid, and cannabinoid-1 sites. Misuse reports in the postmarketing file still exist, mostly in people already using several drugs. The abuse potential was not scored in a dedicated human study. Watch for self-escalation anyway.
Protein binding is negligible and the capsule is not metabolized. That pair is why hepatic impairment studies were skipped and why drug-level 'optimization' is not a Neurontin habit. The molecule leaves in the urine. If the urine output or the creatinine clearance is the weak line, the daily total is the line you change.
07 Section
Shingles pain and add-on seizures are the two US jobs
Postherpetic neuralgia in adults is one labelled job. Adjunctive treatment of partial-onset seizures, with or without secondary generalization, in people aged 3 years and older is the other. Those two lines are the whole US indication set for immediate-release gabapentin.
Diabetic neuropathy, fibromyalgia, and restless legs get written every week in clinic. They are not Neurontin indications. Gabapentin enacarbil sold as Horizant carries restless-legs language. Immediate-release 400 mg capsules do not inherit that sentence.
Three add-on epilepsy trials in 705 people aged 12 and older, plus one pediatric trial in 247 children aged 3 to 12, are the seizure evidence the label summarizes. Enrolled patients still had at least four partial seizures a month on one or more antiepileptic drugs. The primary read was a 50 percent or greater drop in seizure frequency.
Nerve-pain starts are slower than people hope. The PHN schedule on the label is 300 mg on day one, 600 mg on day two as 300 mg twice daily, then 900 mg on day three as 300 mg three times daily, with room to climb toward 1800 mg a day. A 400 mg capsule is a later rung on that ladder, not day one.
Children aged 3 to 11 start by weight, 10 to 15 mg/kg/day in three divided doses, then climb toward 40 mg/kg/day at ages 3 to 4 or 25 to 35 mg/kg/day at ages 5 to 11. An adult 400 mg capsule is the wrong starter for that arithmetic. The oral solution exists for a reason.
08 Section
Horizant and Gralise are other bottles
Gralise is once-daily extended-release gabapentin labelled only for postherpetic neuralgia. Horizant is gabapentin enacarbil, a prodrug, labelled for restless legs and for PHN. Neither is interchangeable milligram-for-milligram with a 400 mg immediate-release capsule.
Scoring a 600 mg or 800 mg Neurontin tablet is a different fill from opening a 400 mg capsule. Oral solution at 250 mg per 5 mL exists for people who cannot swallow shells. Mixing those products in one monthly count is how cash quotes go wrong.
Pregabalin is a related alpha-2-delta ligand with its own label, schedule, and renal table. It is not a 400 mg gabapentin substitute. PDE5 notes on this shelf (tadalafil, sildenafil, vardenafil) do not share a mechanism with Neurontin and are not a workaround for nerve pain.
Approval year for gabapentin in the US is 1993. The capsule colours on the originator line (white 100, yellow 300, orange 400) still help people who grew up on Neurontin names. Generic shells may not keep those colours. Read the milligrams, not the dye.
09 Section
Coming off after weeks, not after a skipped weekend
Minimum one week is the US discontinuation language when Neurontin is stopped or another anticonvulsant is added. UK product information for 400 mg hard capsules is stricter at higher totals and can stretch the step-down to weeks. Either way, a cold stop after regular use is a clinical error.
Seizure frequency can rise if an epilepsy patient stops abruptly. People on the drug for nerve pain more often describe insomnia, anxiety, sweating, and a return of the original burning. Those symptoms are why the taper is part of the same visit that names the 400 mg cost.
A written decrement belongs on the same slip as the last refill. Ingrid's method is Lift the lock, Note the label, Peer-pass the draft, Shelf the note. The shelf does not replace the prescriber who knows the seizure calendar or the shingles scar.
UK 400 mg capsule information can stretch the step-down past one week when the daily total is high (a three-week floor is mentioned around 3600 mg/day). US Neurontin still prints the one-week minimum. Use the longer calendar if the dose was high or the course was long. Do not treat the US floor as a race.
10 Section
Pack the creatinine and the written step-down
Bring three things to the window: the 400 mg capsule strength, the actual count (sixty, ninety, or whatever was written), and the last creatinine clearance or eGFR. Without those, a coupon number is a guess about someone else's bottle.
School or shift work that cannot tolerate the first week's dizziness is a reason to start the climb on a quieter calendar, not a reason to swallow 400 mg three times on day one. The PHN ladder begins at 300 mg for a reason. A first Monday on a night shift is a poor titration day.
Write the taper on the same visit that starts a stop. If an opioid or a night sedative is already on the list, say so before the new capsule is added. Mail a chart question to [email protected] if the published note and the script disagree; we still will not dispense.
Driving waits until the person knows how 400 mg hits them. Somnolence and dizziness are labelled, not optional small print. A first week of three-times-daily capsules is a poor week to sign a long motorway shift or to climb a ladder at work.