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osmolex er

Pharmaranks rates Osmolex ER 3.6/5 for recall safety — an independent score from its FDA recall history and its manufacturer's record. Osmolex ER (Amantadine Hydrochloride) is an influenza a m2 protein inhibitor used to treat Drug-Induced Dyskinesia, Dystonia, Human Influenza, Parkinson Disease.

Amantadine Hydrochloride · by Supernus Pharms

Available as a generic: Amantadine Hydrochloride

72/100Limited · 1 source

Based on 1 source · Recall-safety score from FDA recall history — this product's own recalls and its manufacturer's record. Not an efficacy or quality rating. methodology →

Rated against independent regulatory sources·Last updated October 7, 2026·How we rate
Verified againstopenFDANIH DailyMedRxClass
~$4.63 /30
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Key facts

Active ingredient
Amantadine Hydrochloride
Form
Tablet, extended release
Strength
Amantadine Hydrochloride EQ 129MG Base · Amantadine Hydrochloride EQ 161MG Base · Amantadine Hydrochloride EQ 193MG Base · Amantadine Hydrochloride EQ 258MG Base
Type
Prescription (Rx)
Brand or generic
Brand-name
Manufacturer
Supernus Pharms
Half-life
about 17 hours (range roughly 10 to 25 hours); across studies it has averaged about 16 hours (range 9 to 31 hours) in healthy adults (how long it stays in your system)
What the pharmacy pays
~$4.63 for 30 — not your price
FDA application
NDA209410
Availability
Discontinued (per FDA)

How long does Amantadine Hydrochloride stay in your body?

The elimination half-life of amantadine hydrochloride is about 17 hours (range roughly 10 to 25 hours); across studies it has averaged about 16 hours (range 9 to 31 hours) in healthy adults — the time it takes the body to clear about half of it. As a rule of thumb, a medicine is mostly gone after roughly 4 to 5 half-lives, though this varies from person to person with age and kidney or liver function. Amantadine is excreted mostly unchanged in urine, so its half-life depends heavily on kidney function and age. In healthy elderly adults (age 60+) the half-life rises to about 29 hours (range 20 to 41 hours) as clearance falls. In renal impairment the elimination half-life increases two- to threefold or more when creatinine clearance is below 40 mL/min/1.73 m2, and averages about 8 days in patients on chronic maintenance hemodialysis (amantadine is removed only negligibly by hemodialysis). The label describes no active metabolite that outlasts the parent: the main metabolite, N-acetylamantadine (acetylamantadine), has an unknown contribution to efficacy or toxicity, and amantadine is not a prodrug. The label does not separate a distinct distribution phase, so the reported value is the terminal/elimination half-life.

This is general information, not medical advice. It doesn’t tell you when a drug test would read negative (tests detect substances for different, often longer, windows) or when it’s safe to take another dose — ask your pharmacist or prescriber. Source: Amantadine Hydrochloride FDA label (DailyMed) — Clinical Pharmacology, Pharmacokinetics.

Drug class

May treat (source: NIH RxClass)

Dosage forms

Tablet, extended release

The forms currently marketed in the U.S., per the FDA National Drug Code Directory.

Ways to save

Ask for the generic

Same active ingredient, far cheaper. Is there a generic? →

Request a 90-day supply

Bulk fills usually lower the per-dose price vs monthly refills.

Use copay cards

Manufacturer copay cards & patient-assistance programs — especially for brand drugs.

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Frequently asked questions

What does Osmolex ER treat?
Osmolex ER (Amantadine Hydrochloride) may be used to treat drug-induced dyskinesia, dystonia, human influenza, parkinson disease, secondary parkinson disease, drug-induced akathisia, based on NIH RxClass drug-classification data (conditions a drug may treat — not a verbatim copy of the FDA-approved label). This is general reference, not medical advice.
How is Osmolex ER rated?
pharmaranks gives Osmolex ER a composite score of 3.6 out of 5, currently based on 1 weighted source (FDA regulatory recall-safety data weighted highest). See our methodology at /how-we-rate.
How much does Osmolex ER cost?
Nobody can tell you what you will pay — your price is set by your insurer's formulary, your deductible and the pharmacy's markup, and none of those are published. What IS published is what the pharmacy paid to acquire it: about $4.63 for 30, per the CMS NADAC survey. Treat that as the floor, not the quote — ask the pharmacist for the cash price as well as your copay, because for cheap generics the cash price often wins.
Is there a coupon or discount for Osmolex ER?
pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Osmolex ER. To pay less, ask your prescriber or pharmacist whether a generic equivalent exists, check the manufacturer's copay/savings card and patient-assistance program, and compare a pharmacy discount card against your insurance copay. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
Who makes Osmolex ER?
Osmolex ER is marketed by Supernus Pharms. You can see Supernus Pharms's full profile, rating, and other products on pharmaranks.
Is Osmolex ER a brand-name or generic drug?
Osmolex ER is a brand-name product with the active ingredient Amantadine Hydrochloride. Lower-cost generic equivalents containing Amantadine Hydrochloride are available — ask your pharmacist.
Is Osmolex ER available over the counter?
No. Osmolex ER is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
What forms does Osmolex ER come in?
Osmolex ER is currently marketed as tablet, extended release, per the FDA's National Drug Code Directory.
What class of drug is Osmolex ER?
Osmolex ER is classified as influenza a m2 protein inhibitor, per the FDA's Established Pharmacologic Class.
Is Osmolex ER FDA-registered?
Osmolex ER is on record with the U.S. FDA under application number NDA209410. You can verify this on its official FDA label.
Has Osmolex ER been recalled by the FDA?
Osmolex ER has no FDA recalls recorded under its own application in the openFDA enforcement database. Its recall-safety score reflects its manufacturer's overall recall record. This is general reference, not medical advice — check the FDA recall database for the latest alerts.
Is Osmolex ER safe?
There's no single safe-or-not verdict. pharmaranks gives Osmolex ER a recall-safety score of 72/100, based on its FDA recall history (no recalls under its own FDA application) — not an efficacy or side-effect rating. Review its FDA-label side effects and warnings before use, and always consult a licensed professional.

Information is sourced from public FDA regulatory data. Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.

What people report to the FDA about AMANTADINE HYDROCHLORIDE

The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 2,173 reports naming AMANTADINE HYDROCHLORIDE — the active ingredient in Osmolex ER, and the FDA flagged 75% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:

  • fall175 reports
  • gait disturbance154 reports
  • fatigue136 reports
  • hallucination134 reports
  • speech disorder120 reports
  • dyskinesia114 reports
  • tremor102 reports
  • constipation99 reports

Read these as a signal, not a rate. A report does not mean AMANTADINE HYDROCHLORIDE caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label.

Source: openFDA drug/event (FAERS), retrieved September 25, 2026.

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