Amantadine Hydrochloride 50 mg/5mL Solution, 473 mL
Other active recalls for Amantadine Hydrochloride (different manufacturers) — 1 · tap to view
🆔 Identity & classification
Where does this data come from?
🏷️ RxNorm drug class
This medicine belongs to the Influenza A M2 Protein Inhibitor class.
Where does this data come from?
🏭 Manufacturer & labeler
Where does this data come from?
🩺 Clinical
Amantadine is used to treat the symptoms of Parkinson's disease (PD; a disorder of the nervous system that causes difficulties with movement, muscle control, and balance) and other similar conditions. It is also used to control movement problems that are a side effect of certain medications used to treat Parkinson's disease. Amantadine extended-release capsules (Gocovri®) are used along with the combination of levodopa and carbidopa (Rytary®, Sinemet®) to treat ''off'' episodes (times of difficulty moving, walking, and speaking that may happen when other medications wear off) in people with Pa...
Read the full MedlinePlus article ↗- Amantadine only works against influenza A — it won't help with influenza B, COVID-19, colds, or stomach bugs. And it works best for the flu when you start it early in the illness....
- Can I take amantadine to treat a regular flu or a stomach bug?
- The ones that matter most are hallucinations (seeing or hearing things that aren't there), significant dizziness — especially when you stand up — and any vision changes like sudden...
- I take amantadine for Parkinson's — what side effects should I actually watch for?
Patient education
Supplement & herbal interactions
Where does this data come from?
Ask a licensed pharmacist directly — free, answered by our team.
💊 What it looks like
Where does this data come from?
🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
-
UNII 8SKN0B0MIM
Benzoic acid is a naturally occurring organic acid used as a preservative in medicines and foods. It helps prevent bacterial and fungal growth to extend shelf life and maintain product stability.
-
UNII 2968PHW8QP
A weak organic acid derived from citrus fruits or made through fermentation. It works as a buffer to control pH, a preservative to extend shelf life, and a flavoring agent in medications.
-
UNII 8KW3E207O2
A liquid sweetener made from sorbitol, a sugar alcohol derived from glucose. It sweetens the medicine and also acts as a humectant to help retain moisture and improve texture in liquid formulations.
-
UNII 96K6UQ3ZD4
Sucralose is a synthetic sweetener made from sugar. It's added to medicines to improve taste without adding calories, helping make bitter or unpleasant-tasting drugs easier to take.
-
UNII 059QF0KO0R
Water is a liquid solvent that dissolves and mixes ingredients together in liquid medicines, syrups, and injections. It helps distribute the active drug evenly throughout the product.
5 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
Are inactive ingredients the same for every manufacturer?
Why might an inactive ingredient be missing?
Can inactive ingredients matter?
💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $0.049 | $23.27 / 473 ml |
| Medicaid paysCMS SDUD · 12 mo | $0.0740 | $35.00 / 473 ml |
| Medicare drug plans payPart D · Q2 2026 | $0.0714 | $33.77 / 473 ml |
Where does this data come from?
🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Amantadine 50 mg/5mL 00116-4010-16 | Xttrium | 473 ml | $0.049 | AA | Availability likely | — |
| Amantadine Hydrochloride 50 mg/5mLthis 39328-0530-16 | Patrin | 473 ml | $0.049 | AA | Availability likely | — |
| Amantadine Hydrochloride 50 mg/5mL 62135-0010-47 | Chartwell | 473 ml | $0.049 | AA | Availability likely | — |
| Amantadine Hydrochloride 50 mg/5mL 00121-0646-10 | PAI | 10 cups | — | AA | FDA listed | — |
| Amantadine Hydrochloride 50 mg/5mL 17856-0646-01 | ATLANTIC | 72 cups | — | AA | FDA listed | — |
| Amantadine 50 mg/5mL 50268-0036-14 | AvPAK | 10 cups | — | AA | FDA listed | — |
| Amantadine Hydrochloride 50 mg/5mL 55154-9444-05 | Cardinal | 5 cups | — | AA | FDA listed | — |
| Amantadine Hydrochloride 50 mg/5mL 60687-0797-56 | American | 10 cups | — | AA | FDA listed | — |
| Amantadine Hydrochloride 50 mg/5mL 61037-0484-03 | BAJAJ | 473 ml | — | — | FDA listed | — |
| Amantadine Hydrochloride 100 mg/10mL 62135-0011-24 | Chartwell | 10 cups | — | AA | FDA listed | — |
| Amantadine Hydrochloride 100 mg/10mL 68999-0011-24 | Chartwell | 10 cups | — | AA | FDA listed | — |
Where does this data come from?
⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
Where does this data come from?
🗺️ Medicaid utilization & spend
💊 Medicaid utilization by pack size
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
Where does this data come from?
📦 Packaging — all sizes for this product
| Package NDC | Description | Per unit | Per pack | Marketing start | Status |
|---|---|---|---|---|---|
| 39328-0530-10 | 10 TRAY in 1 CASE (39328-530-10) / 10 CUP, UNIT-DOSE in 1 TRAY / 10 mL in 1 CUP, UNIT-DOSE (39328-530-01) | — | — | 2023-08-11 | Active |
| 39328-0530-16 You're viewing this | 473 mL in 1 BOTTLE, PLASTIC (39328-530-16) | $0.0492 / mL | $23.28 | 2023-08-11 | Active |
| 39328-0530-99 | 10 TRAY in 1 CASE (39328-530-99) / 10 CUP, UNIT-DOSE in 1 TRAY / 10 mL in 1 CUP, UNIT-DOSE (39328-530-10) | — | — | 2024-05-08 | Active |
In Medicaid, this is the most-dispensed pack of this product — about 100% of fills over the last four reported quarters. See all packs ↓
Pack size FAQ
What quantity is in NDC 39328-0530-16?
What NDC number is used to bill for this package of Amantadine Hydrochloride 50 mg/5mL Solution?
Prices are the latest CMS NADAC pharmacy acquisition cost per NDC; per-pack figures are per-unit × pack quantity, shown only when the pack is denominated in the same measure NADAC prices.
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
INDICATIONS AND USAGE Amantadine Hydrochloride Oral Solution USP is indicated for the prophylaxis and treatment of signs and symptoms of infection caused by various strains of influenza A virus. Amantadine Hydrochloride Oral Solution USP is also indicated in the treatment of parkinsonism and drug-induced extrapyramidal reactions. Influenza A Prophylaxis Amantadine Hydrochloride Oral Solution USP is indicated for chemoprophylaxis against signs and symptoms of influenza A virus infection.
Because Amantadine Hydrochloride Oral Solution USP does not completely prevent the host immune response to influenza A infection, individuals who take this drug may still develop immune responses to natural disease or vaccination and may be protected when later exposed to antigenically related viruses. Following vaccination during an influenza A outbreak, Amantadine Hydrochloride Oral Solution USP prophylaxis should be considered for the 2- to 4-week time period required to develop an antibody response. Influenza A Treatment Amantadine Hydrochloride Oral Solution USP is also indicated in the treatment of uncomplicated respiratory tract illness caused by influenza A virus strains especially when administered early in the course of illness.
There are no well-controlled clinical studies demonstrating that treatment with Amantadine Hydrochloride Oral Solution USP will avoid the development of influenza A virus pneumonitis or other complications in high risk patients. There is no clinical evidence indicating that Amantadine Hydrochloride Oral Solution USP is effective in the prophylaxis or treatment of viral respiratory tract illnesses other than those caused by influenza A v irus strains. The following points should be considered before initiating treatment or prophylaxis with Amantadine Hydrochloride Oral Solution USP: Amantadine Hydrochloride Oral Solution USP is not a substitute for early vaccination on an annual basis as recommended by the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices.
Influenza viruses change over time. Emergence of resistance mutations could decrease drug effectiveness. Other factors (for example, changes in viral virulence) might also diminish clinical benefit of antiviral drugs.
Prescribers should consider available information on influenza drug susceptibility patterns and treatment effects when deciding whether to use Amantadine Hydrochloride Oral Solution USP. Parkinson's Disease/Syndrome Amantadine Hydrochloride Oral Solution USP is indicated in the treatment of idiopathic Parkinson's disease (Paralysis Agitans), postencephalitic parkinsonism, and symptomatic parkinsonism which may follow injury to the nervous system by carbon monoxide intoxication. It is indicated in those elderly patients believed to develop parkinsonism in association with cerebral arteriosclerosis.
In the treatment of Parkinson's disease, Amantadine Hydrochloride Oral Solution USP is less effective than levodopa,(-)-3-(3,4dihydroxyphenyl)-L-alanine, and its efficacy in comparison with the anticholinergic antiparkinson drugs has not yet been established. Drug-Induced Extrapyramidal Reactions Amantadine Hydrochloride Oral Solution USP is indicated in the treatment of drug-induced extrapyramidal reactions. Although anticholinergic-type side effects have been noted with Amantadine Hydrochloride Oral Solution USP when used in patients with drug-induced extrapyramidal reactions, there is a lower incidence of these side effects than that observed with the anticholinergic antiparkinson drugs.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION The dose of Amantadine Hydrochloride Oral Solution USP (Amantadine Hydrochloride, USP) may need reduction in patients with congestive heart failure, peripheral edema, orthostatic hypotension, or impaired renal function (see Dosage for Impaired Renal Function ). Dosage for Prophylaxis and Treatment of Uncomplicated Influenza A Virus Illness Adult The adult daily dosage of Amantadine Hydrochloride Oral Solution USP is 200 mg; two 100 mg tablets (or four teaspoonfuls of syrup) as a single daily dose.
The daily dosage may be split into one tablet of 100 mg (or two teaspoonfuls of syrup) twice a day. If central nervous system effects develop in once-a-day dosage, a split dosage schedule may reduce such complaints. In persons 65 years of age or older, the daily dosage of Amantadine Hydrochloride Oral Solution USP is 100 mg.
A 100 mg daily dose has also been shown in experimental challenge studies to be effective as prophylaxis in healthy adults who are not at high risk for influenza-related complications. However, it has not been demonstrated that a 100 mg daily dose is as effective as a 200 mg daily dose for prophylaxis, nor has the 100 mg daily dose been studied in the treatment of acute influenza illness. In recent clinical trials, the incidence of central nervous system (CNS) side effects associated with the 100 mg daily dose was at or near the level of placebo.
The 100 mg dose is recommended for persons who have demonstrated intolerance to 200 mg of Amantadine Hydrochloride Oral Solution USP daily because of CNS or other toxicities. Pediatric Patients 1 yr.-9 yrs. of age The total daily dose should be calculated on the basis of 2 to 4 mg/lb/day (4.4 to 8.8 mg/kg/day), but not to exceed 150 mg per day. 9 yrs.-12 yrs. of age The total daily dose is 200 mg given as one tablet of 100 mg (or two teaspoonfuls of syrup) twice a day.
The 100 mg daily dose has not been studied in this pediatric population. Therefore, there are no data which demonstrate that this dose is as effective as or is safer than the 200 mg daily dose in this patient population. Prophylactic dosing should be started in anticipation of an influenza A outbreak and before or after contact with individuals with influenza A virus respiratory tract illness.
Amantadine Hydrochloride Oral Solution USP should be continued daily for at least 10 days following a known exposure. If Amantadine Hydrochloride Oral Solution USP is used chemoprophylactically in conjunction with inactivated influenza A virus vaccine until protective antibody responses develop, then it should be administered for 2 to 4 weeks after the vaccine has been given. When inactivated influenza A virus vaccine is unavailable or contraindicated, Amantadine Hydrochloride Oral Solution USP should be administered for the duration of known influenza A in the community because of repeated and unknown exposure.
Treatment of influenza A virus illness should be started as soon as possible, preferably within 24 to 48 hours after onset of signs and symptoms, and should be continued for 24 to 48 hours after the disappearance of signs and symptoms. Dosage for Parkinsonism Adult The usual dose of Amantadine Hydrochloride Oral Solution USP is 100 mg twice a day when used alone. Amantadine Hydrochloride Oral Solution USP has an onset of action usually within 48 hours.
The initial dose of Amantadine Hydrochloride Oral Solution USP is 100 mg daily for patients with serious associated medical illnesses or who are receiving high doses of other antiparkinson drugs. After one to several weeks at 100 mg once daily, the dose may be increased to 100 mg twice daily, if necessary. Occasionally, patients whose responses are not optimal with Amantadine Hydrochloride Oral Solution USP at 200 mg daily may benefit from an increase up to 400 mg daily in divided doses.
However, such patients should be supervised closely by their physicians. Patients initially deriving benefit from Amantadine Hydrochloride Oral Soluti…
⛔ Contraindications ▾
CONTRAINDICATIONS Amantadine Hydrochloride Oral Solution USP is contraindicated in patients with known hypersensitivity to amantadine hydrochloride or to any of the other ingredients in Amantadine Hydrochloride Oral Solution USP.
⚠️ Warnings ▾
WARNINGS Deaths Deaths have been reported from overdose with Amantadine Hydrochloride Oral Solution USP. The lowest reported acute lethal dose was 1 gram. Acute toxicity may be attributable to the anticholinergic effects of amantadine.
Drug overdose has resulted in cardiac, respiratory, renal or central nervous system toxicity. Cardiac dysfunction includes arrhythmia, tachycardia and hypertension (see OVERDOSAGE ). Deaths due to drug accumulation (overdosage) have been reported in patients with renal impairment, who were prescribed higher than recommended doses of Amantadine Hydrochloride for their level of renal function (see DOSAGE AND ADMINISTRATION; Dosage of Impaired Renal Function and OVERDOSAGE ).
Suicide Attempts Suicide attempts, some of which have been fatal, have been reported in patients treated with Amantadine Hydrochloride Oral Solution USP, many of whom received short courses for influenza treatment or prophylaxis. The incidence of suicide attempts is not known and the pathophysiologic mechanism is not understood. Suicide attempts and suicidal ideation have been reported in patients with and without prior history of psychiatric illness.
Amantadine Hydrochloride Oral Solution USP can exacerbate mental problems in patients with a history of psychiatric disorders or substance abuse. Patients who attempt suicide may exhibit abnormal mental states which include disorientation, confusion, depression, personality changes, agitation, aggressive behavior, hallucinations, paranoia, other psychotic reactions, and somnolence or insomnia. Because of the possibility of serious adverse effects, caution should be observed when prescribing Amantadine Hydrochloride Oral Solution USP to patients being treated with drugs having CNS effects, or for whom the potential risks outweigh the benefit of treatment.
CNS Effects Patients with a history of epilepsy or other "seizures" should be observed closely for possible increased seizure activity. Patients receiving Amantadine Hydrochloride Oral Solution USP who note central nervous system effects or blurring of vision should be cautioned against driving or working in situations where alertness and adequate motor coordination are important. Other Patients with a history of congestive heart failure or peripheral edema should be followed closely as there are patients who developed congestive heart failure while receiving Amantadine Hydrochloride Oral Solution USP.
Patients with Parkinson's disease improving on Amantadine Hydrochloride Oral Solution USP should resume normal activities gradually and cautiously, consistent with other medical considerations, such as the presence of osteoporosis or phlebothrombosis. Because Amantadine Hydrochloride Oral Solution USP has anticholinergic effects and may cause mydriasis, it should not be given to patients with untreated angle closure glaucoma.
🤒 Adverse Reactions ▾
ADVERSE REACTIONS To report SUSPECTED ADVERSE REACTIONS contact FDA at 1-800-FDA-1088 or go to www.fda.gov/medwatch. The adverse reactions reported most frequently at the recommended dose of Amantadine Hydrochloride Oral Solution USP (5-10%) are: nausea, dizziness (lightheadedness), and insomnia. Less frequently (1-5%) reported adverse reactions are: depression, anxiety and irritability, hallucinations, confusion, anorexia, dry mouth, constipation, ataxia, livedo reticularis, peripheral edema, orthostatic hypotension, headache, somnolence, nervousness, dream abnormality, agitation, dry nose, diarrhea and fatigue.
Infrequently (0.1-1%) occurring adverse reactions are: congestive heart failure, psychosis, urinary retention, dyspnea, skin rash, vomiting, weakness, slurred speech, euphoria, thinking abnormality, amnesia, hyperkinesia, hypertension, decreased libido, and visual disturbance, including punctate subepithelial or other corneal opacity, corneal edema, decreased visual acuity, sensitivity to light, and optic nerve palsy. Rare (less than 0.1%) occurring adverse reactions are: instances of convulsion, leukopenia, neutropenia, eczematoid dermatitis, oculogyric episodes, suicidal attempt, suicide, and suicidal ideation (see WARNINGS ).
Other adverse reactions reported during postmarketing experience with Amantadine Hydrochloride Oral Solution USP usage include: Nervous System/Psychiatric coma, stupor, delirium, hypokinesia, hypertonia, delusions, aggressive behavior, paranoid reaction, manic reaction, involuntary muscle contractions, gait abnormalities, paresthesia, EEG changes, and tremor. Abrupt discontinuation may also precipitate delirium, agitation, delusions, hallucinations, paranoid reaction, stupor, anxiety, depression and slurred speech; Cardiovascular cardiac arrest, arrhythmias including malignant arrhythmias, hypotension, and tachycardia; Respiratory acute respiratory failure, pulmonary edema, and tachypnea; Gastrointestinal dysphagia; Hematologic leukocytosis; agranulocytosis Special Senses keratitis and mydriasis; Skin and Appendages pruritus and diaphoresis; Miscellaneous neuroleptic malignant syndrome (see WARNINGS ), allergic reactions including anaphylactic reactions, edema and fever.
Laboratory Test elevated: CPK, BUN, serum creatinine, alkaline phosphatase, LDH, bilirubin, GGT, SGOT, and SGPT.
🔄 Drug Interactions ▾
Drug Interactions Careful observation is required when Amantadine Hydrochloride Oral Solution USP is administered concurrently with central nervous system stimulants. Agents with anticholinergic properties may potentiate the anticholinergic-like side effects of amantadine. Coadministration of thioridazine has been reported to worsen the tremor in elderly patients with Parkinson's disease, however, it is not known if other phenothiazines produce a similar response.
Coadministration of Dyazide (triamterene/hydrochlorothiazide) resulted in a higher plasma amantadine concentration in a 61-year-old man receiving Amantadine Hydrochloride Oral Solution USP (Amantadine Hydrochloride, USP) 100 mg TID for Parkinson's disease.1 It is not known which of the components of Dyazide contributed to the observation or if related drugs produce a similar response. Coadministration of quinine or quinidine with amantadine was shown to reduce the renal clearance of amantadine by about 30%. The concurrent use of Amantadine Hydrochloride Oral Solution USP with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated.
However, because of the potential for interference between these products, LAIV should not be administered within 2 weeks before or 48 hours after administration of Amantadine Hydrochloride Oral Solution USP, unless medically indicated. The concern about possible interference arises from the potential for antiviral drugs to inhibit replication of live vaccine virus. Trivalent inactivated influenza vaccine can be administered at any time relative to use of Amantadine Hydrochloride Oral Solution USP.
🤰 Pregnancy ▾
Pregnancy Category C The effect of amantadine on embryofetal and peri-postnatal development has not been adequately tested, that is, in studies conducted under Good Laboratory Practice (GLP) and according to current recommended methodology. However, in two non-GLP studies in rats in which females were dosed from 5 days prior to mating to Day 6 of gestation or on Days 7-14 of gestation, Amantadine Hydrochloride Oral Solution USP produced increases in embryonic death at an oral dose of 100 mg/kg (or 3 times the maximum recommended human dose on a mg/m2 basis).
In the non-GLP rat study in which females were dosed on Days 7-14 of gestation, there was a marked increase in severe visceral and skeletal malformations at oral doses of 50 and 100 mg/kg (or 1.5 and 3 times, respectively, the maximum recommended human dose on a mg/m2 basis). The no-effect dose for teratogenicity was 37 mg/kg (equal to the maximum recommended human dose on a mg/m2 basis). The safety margins reported may not accurately reflect the risk considering the questionable quality of the study on which they are based.
There are no adequate and well- controlled studies in pregnant women. Human data regarding teratogenicity after maternal use of amantadine is scarce. Tetralogy of Fallot and tibial hemimelia (normal karyotype) occurred in an infant exposed to amantadine during the first trimester of pregnancy (100 mg P.O. for 7 days during the 6th and 7th week of gestation).
Cardiovascular maldevelopment (single ventricle with pulmonary atresia) was associated with maternal exposure to amantadine (100 mg/d) administered during the first 2 weeks of pregnancy. Amantadine Hydrochloride Oral Solution USP should be used during pregnancy only if the potential benefit justifies the potential risk to the embryo or fetus.
🧒 Pediatric Use ▾
Pediatric Use The safety and efficacy of Amantadine Hydrochloride Oral Solution USP in newborn infants and infants below the age of 1 year have not been established.
🆘 Overdosage ▾
OVERDOSAGE Deaths have been reported from overdose with Amantadine Hydrochloride Oral Solution USP. The lowest reported acute lethal dose was 1 gram. Because some patients have attempted suicide by overdosing with amantadine, prescriptions should be written for the smallest quantity consistent with good patient management.
Acute toxicity may be attributable to the anticholinergic effects of amantadine. Drug overdose has resulted in cardiac, respiratory, renal or central nervous system toxicity. Cardiac dysfunction includes arrhythmia, tachycardia and hypertension.
Pulmonary edema and respiratory distress (including adult respiratory distress syndrome - ARDS) have been reported; renal dysfunction including increased BUN, decreased creatinine clearance and renal insufficiency can occur. Central nervous system effects that have been reported include insomnia, anxiety, agitation, aggressive behavior, hypertonia, hyperkinesia, ataxia, gait abnormality, tremor, confusion, disorientation, depersonalization, fear, delirium, hallucinations, psychotic reactions, lethargy, somnolence and coma.
Seizures may be exacerbated in patients with prior history of seizure disorders. Hyperthermia has also been observed in cases where a drug overdose has occurred. There is no specific antidote for an overdose of Amantadine Hydrochloride Oral Solution USP.
However, slowly administered intravenous physostigmine in 1 and 2 mg doses in an adult 2 at 1- to 2-hour intervals and 0.5 mg doses in a child3 at 5- to 10-minute intervals up to a maximum of 2 mg/hour have been reported to be effective in the control of central nervous system toxicity caused by amantadine hydrochloride. For acute overdosing, general supportive measures should be employed along with immediate gastric lavage or induction of emesis. Fluids should be forced, and if necessary, given intravenously.
The pH of the urine has been reported to influence the excretion rate of Amantadine Hydrochloride Oral Solution USP. Since the excretion rate of Amantadine Hydrochloride Oral Solution USP increases rapidly when the urine is acidic, the administration of urine acidifying drugs may increase the elimination of the drug from the body. The blood pressure, pulse, respiration and temperature should be monitored.
The patient should be observed for hyperactivity and convulsions; if required, sedation, and anticonvulsant therapy should be administered. The patient should be observed for the possible development of arrhythmias and hypotension; if required, appropriate antiarrhythmic and antihypotensive therapy should be given. Electrocardiographic monitoring may be required after ingestion, since malignant tachyarrhythmias can appear after overdose.
Care should be exercised when administering adrenergic agents, such as isoproterenol, to patients with an Amantadine Hydrochloride Oral Solution USP overdose, since the dopaminergic activity of Amantadine Hydrochloride Oral Solution USP has been reported to induce malignant arrhythmias. The blood electrolytes, urine pH and urinary output should be monitored. If there is no record of recent voiding, catheterization should be done.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Pharmacodynamics Mechanism of Action Antiviral The mechanism by which amantadine exerts its antiviral activity is not clearly understood. It appears to mainly prevent the release of infectious viral nucleic acid into the host cell by interfering with the function of the transmembrane domain of the viral M2 protein. In certain cases, amantadine is also known to prevent virus assembly during virus replication.
It does not appear to interfere with the immunogenicity of inactivated influenza A virus vaccine. Antiviral Activity Amantadine inhibits the replication of influenza A virus isolates from each of the subtypes, i.e., H1N1, H2N2 and H3N2. It has very little or no activity against influenza B virus isolates.
A quantitative relationship between the in vitro susceptibility of influenza A virus to amantadine and the clinical response to therapy has not been established in man. Sensitivity test results, expressed as the concentration of amantadine required to inhibit by 50% the growth of virus (ED 50 ) in tissue culture vary greatly (from 0.1 μg/mL to 25.0 µg/mL) depending upon the assay protocol used, size of virus inoculum, isolates of influenza A virus strains tested, and the cell type used. Host cells in tissue culture readily tolerated amantadine up to a concentration of 100 µg/mL.
Drug Resistance Influenza A variants with reduced in vitro sensitivity to amantadine have been isolated from epidemic strains in areas where adamantane derivatives are being used. Influenza viruses with reduced in vitro sensitivity have been shown to be transmissible and to cause typical influenza illness. The quantitative relationship between the in vitro sensitivity of influenza A variants to amantadine and the clinical response to therapy has not been established.
Mechanism of Action Parkinson's Disease The mechanism of action of amantadine in the treatment of Parkinson's disease and drug- induced extrapyramidal reactions is not known. Data from earlier animal studies suggest that Amantadine Hydrochloride Oral Solution USP may have direct and indirect effects on dopamine neurons. More recent studies have demonstrated that amantadine is a weak, non-competitive NMDA receptor antagonist (K i = 10µM).
Although amantadine has not been shown to possess direct anticholinergic activity in animal studies, clinically, it exhibits anticholinergic-like side effects such as dry mouth, urinary retention, and constipation. Pharmacokinetics Amantadine Hydrochloride Oral Solution USP is well absorbed orally. Maximum plasma concentrations are directly related to dose for doses up to 200 mg/day.
Doses above 200 mg/day may result in a greater than proportional increase in maximum plasma concentrations. It is primarily excreted unchanged in the urine by glomerular filtration and tubular secretion. Eight metabolites of amantadine have been identified in human urine.
One metabolite, an N-acetylated compound, was quantified in human urine and accounted for 5-15% of the administered dose. Plasma acetylamantadine accounted for up to 80% of the concurrent amantadine plasma concentration in 5 of 12 healthy volunteers following the ingestion of a 200 mg dose of amantadine. Acetylamantadine was not detected in the plasma of the remaining seven volunteers.
The contribution of this metabolite to efficacy or toxicity is not known. There appears to be a relationship between plasma amantadine concentrations and toxicity. As concentration increases, toxicity seems to be more prevalent, however, absolute values of amantadine concentrations associated with adverse effects have not been fully defined.
Amantadine pharmacokinetics were determined in 24 normal adult male volunteers after the oral administration of a single amantadine hydrochloride 100 mg soft gel capsule. The mean ± SD maximum plasma concentration was 0.22 ± 0.03 µg/mL (range: 0.18 to 0.32 µg/mL). The time to peak concentration was 3.3 ± 1.5 hours (range: 1.5 to 8.0 hours).
The apparent oral clear…
🧬 Mechanism of Action ▾
Mechanism of Action Antiviral The mechanism by which amantadine exerts its antiviral activity is not clearly understood. It appears to mainly prevent the release of infectious viral nucleic acid into the host cell by interfering with the function of the transmembrane domain of the viral M2 protein. In certain cases, amantadine is also known to prevent virus assembly during virus replication.
It does not appear to interfere with the immunogenicity of inactivated influenza A virus vaccine.
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED As a clear, colorless to pale yellow liquid [each 5 mL (1 teaspoonful) contains 50 mg amantadine hydrochloride] in: NDC 39328-530-16 16 oz (473 mL) bottles NDC 39328-530-10 10 mL unit dose cup NDC 39328-530-99 Case contains 100 unit dose cups of 10 mL Store at 20°-25°C (68°-77°F), excursions permitted to 15°-30°C (59°-86°F). [See USP Controlled Room Temperature]. Dispense in a tight container as defined in the USP, with a child-resistant closure (as required).
📦 Storage and Handling ▾
Store at 20°-25°C (68°-77°F), excursions permitted to 15°-30°C (59°-86°F). [See USP Controlled Room Temperature]. Dispense in a tight container as defined in the USP, with a child-resistant closure (as required).
📋 Description ▾
DESCRIPTION Amantadine Hydrochloride Oral Solution, USP is designated generically as amantadine hydrochloride and chemically as 1-adamantanamine hydrochloride. Amantadine hydrochloride is a stable white or nearly white crystalline powder, freely soluble in water and soluble in alcohol and in chloroform. Amantadine hydrochloride has pharmacological actions as both an anti-Parkinson and an antiviral drug.
Amantadine Hydrochloride is available as an oral solution. Amantadine Hydrochloride Oral Solution USP contains 50 mg of amantadine hydrochloride per 5 mL and has the following inactive ingredients: natural raspberry flavor, citric acid monohydrate, benzoic acid, purified water, sucralose and sorbitol solution. Chemical Structure
💬 Information for Patients ▾
Information for Patients Patients should be advised of the following information: Blurry vision and/or impaired mental acuity may occur. Gradually increase physical activity as the symptoms of Parkinson's disease improve. Avoid excessive alcohol usage, since it may increase the potential for CNS effects such as dizziness, confusion, lightheadedness and orthostatic hypotension.
Avoid getting up suddenly from a sitting or lying position. If dizziness or lightheadedness occurs, notify physician. Notify physician if mood/mental changes, swelling of extremities, difficulty urinating and/or shortness of breath occur.
Do not take more medication than prescribed because of the risk of overdose. If there is no improvement in a few days, or if medication appears less effective after a few weeks, discuss with a physician. Consult physician before discontinuing medication.
Seek medical attention immediately if it is suspected that an overdose of medication has been taken.