Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
AMANTADINE vs ACTIQ
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Amantadine is an antiviral and antiparkinsonian agent. Its antiviral mechanism involves inhibition of viral uncoating, thereby blocking influenza A M2 ion channel. In Parkinson's disease, it is thought to increase dopamine release and inhibit its reuptake, and may also have anticholinergic and NMDA receptor antagonist effects.
Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.
Influenza A virus infection (prophylaxis and treatment),Parkinson's disease (symptomatic treatment),Drug-induced extrapyramidal reactions
Management of breakthrough pain in cancer patients aged 16 and older who are already receiving and tolerant to opioid therapy for their underlying persistent cancer pain
100 mg orally twice daily for Parkinson's disease; 100 mg orally twice daily for influenza A prophylaxis/treatment (up to 200 mg/day).
200 mcg transmucosally, titrated upward as needed; initial dose for opioid-tolerant patients is 200 mcg, with additional doses possible after 15 minutes if needed. Maximum 4 doses per episode. At least 4 hours between episodes.
Terminal elimination half-life: 10-14 hours in young adults, up to 24 hours in elderly; prolonged to >24 hours in renal impairment
Terminal half-life 0.83–2 hours (mean 1.3 h) in adults; note that context: transmucosal absorption leads to rapid onset but short duration; half-life is not correlated with clinical effect due to oral transmucosal route and rapid redistribution.
Amantadine is primarily excreted unchanged in urine via glomerular filtration and tubular secretion. It undergoes minimal hepatic metabolism (less than 10%) with no major identified metabolites.
Primarily hepatic via CYP3A4 to inactive metabolites (norfentanyl, despropionylfentanyl, hydroxyfentanyl) and other metabolites; <7% excreted unchanged in urine.
Renal: 90% as unchanged drug via glomerular filtration and tubular secretion; fecal: <10%
Primarily renal as metabolites (about 75% as metabolites, <10% unchanged). Fecal excretion accounts for <9%. Biliary excretion is minor.
60-70% bound, primarily to albumin
Fentanyl is 80–85% bound to plasma proteins (primarily albumin and α1-acid glycoprotein).
Vd: 4-10 L/kg; indicates extensive tissue binding and penetration into brain (CSF: 50-80% of plasma concentration)
Approximately 4 L/kg (range 3–6 L/kg); large Vd indicates extensive tissue distribution and redistribution contributing to short duration.
Oral: 86-90%; IV: 100%
Oral transmucosal: 50% (range 47–54%) relative to IV; variable and enhanced by rapid absorption through buccal mucosa.
Cr Cl 30-50 m L/min: 100 mg once daily; Cr Cl 15-29 m L/min: 100 mg every other day; Cr Cl <15 m L/min or hemodialysis: 200 mg every 7 days.
No specific GFR-based dose adjustment recommended; use with caution in severe renal impairment (Cr Cl < 30 m L/min) and consider dose reduction due to potential accumulation.
No specific Child-Pugh adjustments; use caution in severe hepatic impairment due to potential toxicity.
Child-Pugh Class A/B: No adjustment. Child-Pugh Class C: Reduce initial dose to 100 mcg and titrate slowly; monitor closely for prolonged effects.
Influenza A prophylaxis/treatment: 1-9 years: 5 mg/kg/day (max 150 mg/day) in 2 divided doses; 10-12 years: 100 mg twice daily; 13-16 years: 100 mg twice daily. Parkinson's: not recommended.
Not approved for pediatric use; safety and efficacy not established in patients under 16 years.
Use lower starting dose (100 mg daily) due to age-related renal decline; frequent monitoring for neuropsychiatric effects.
Initiate at 100 mcg transmucosally; titrate slowly due to increased sensitivity and risk of respiratory depression. Monitor for adverse effects.
None.
Risk of respiratory depression, addiction, abuse, and misuse; accidental ingestion can be fatal; concomitant use with benzodiazepines or CNS depressants may cause profound sedation, respiratory depression, coma, and death; not for use in opioid non-tolerant patients; risk of neonatal opioid withdrawal syndrome with prolonged use during pregnancy; serious, life-threatening, or fatal respiratory depression may occur even at recommended doses.
Can cause CNS effects such as confusion, hallucinations, and seizures, especially in elderly or those with renal impairment,May exacerbate psychiatric disorders,Abrupt discontinuation may precipitate parkinsonian crisis or neuroleptic malignant syndrome in patients with Parkinson's disease,Avoid in patients with uncontrolled epilepsy,Renal dose adjustment required
Risk of respiratory depression; addiction, abuse, and misuse; interactions with CNS depressants; serotonin syndrome; adrenal insufficiency; severe hypotension; seizures; withdrawal; use in patients with head injuries, increased intracranial pressure, biliary tract disease, pancreatitis; risk of choking with lozenge; oral mucosal irritation; dental caries; hypokalemia; hyponatremia; use in elderly, cachectic, or debilitated patients.
Hypersensitivity to amantadine or any component,Severe uncontrolled epilepsy,Concomitant use with live attenuated influenza vaccine (since antiviral activity may impair vaccine efficacy)
Significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or without resuscitative equipment; known or suspected paralytic ileus; hypersensitivity to fentanyl or any component; opioid non-tolerant patients; management of acute or postoperative pain including headache/migraine, dental pain, or emergency department use.
No specific food interactions. Avoid alcohol and limit caffeine intake due to potential increased CNS effects. Take with food if gastrointestinal upset occurs.
No significant food interactions. Grapefruit juice may increase fentanyl levels, but specific studies with ACTIQ are lacking. Avoid alcohol, as it may increase sedation and respiratory depression risk.
FDA Pregnancy Category C. First trimester: Associated with cardiovascular malformations (e.g., Ebstein anomaly) in retrospective studies; risk approximately 1-2% absolute. Second and third trimesters: Limited data; theoretical risk of fetal tachyarrhythmia and neurobehavioral effects. Human data insufficient to exclude risk.
FDA Pregnancy Category C. First trimester: limited human data; animal studies show increased resorptions and fetal growth restriction. Second/third trimester: chronic use may cause neonatal opioid withdrawal syndrome; avoid use during labor due to risk of neonatal respiratory depression.
Amantadine is excreted into breast milk with an M/P ratio of approximately 0.5. Limited human data; potential for adverse effects in nursing infants (e.g., irritability, urinary retention). Caution advised; use only if potential benefit outweighs risk.
Excreted in breast milk; M/P ratio not established. Limited data suggest low levels, but risk of infant sedation and respiratory depression. Avoid use while breastfeeding unless potential benefit outweighs risk.
No specific pregnancy-related dosing adjustments established. Pharmacokinetic changes in pregnancy (increased renal clearance) may reduce serum levels; monitor clinical response and consider dose adjustment if efficacy wanes. Maximum dose 200 mg/day.
Due to increased plasma volume and hepatic metabolism in pregnancy, dose requirements may increase; adjust based on clinical response and tolerance. Avoid use during labor and delivery due to risk of neonatal respiratory depression; short-term use preferred.
Amantadine is an antiviral and antiparkinsonian agent with NMDA receptor antagonist properties. For Parkinson's disease, it improves dyskinesias, especially levodopa-induced dyskinesias. For influenza A, it is less effective than neuraminidase inhibitors and resistance is common. Monitor for CNS effects (confusion, hallucinations, nightmares) especially in elderly or renally impaired patients. Dose adjustment required for Cr Cl <50 m L/min. Do not discontinue abruptly in Parkinson's disease due to risk of neuroleptic malignant syndrome.
ACTIQ is a transmucosal immediate-release fentanyl formulation indicated for breakthrough cancer pain in opioid-tolerant patients. Initiate with the lowest strength (200 mcg) and titrate upward. Avoid use in opioid-naive patients due to risk of fatal respiratory depression. Place the unit between cheek and lower gum, not sublingually. Instruct patient not to bite or suck the unit. Monitor for sedation and respiratory depression. Multiple units may be used per episode if needed, but wait at least 4 hours before next episode. Dispose of partially used units by flushing down toilet.
Take exactly as prescribed; do not stop suddenly without consulting your doctor.,Avoid alcohol as it may increase dizziness or confusion.,Report any unusual thoughts, hallucinations, or severe confusion to your healthcare provider immediately.,If you have Parkinson's disease, this medicine helps control symptoms but does not cure it.,If you are taking for influenza, finish the full course even if you feel better.,May cause blurred vision or dizziness; avoid driving or operating machinery until you know how it affects you.,Stay hydrated but avoid excessive caffeine as it may exacerbate side effects.
Only use ACTIQ if you are already taking regular around-the-clock opioid pain medicine and are tolerant to opioids.,Do not use ACTIQ for short-term pain like after surgery, headache, or dental pain.,Place the unit in your cheek pouch, not under your tongue. Do not chew or suck it.,If you need more than 4 units per day, contact your doctor as your dose may need adjustment.,Store ACTIQ in a safe place away from children, as accidental ingestion can be fatal.,Dispose of unused or partially used units by flushing them down the toilet.
"Concurrent administration of naloxegol, a peripherally-acting mu-opioid receptor antagonist, may increase the serum concentration of amantadine, a weak NMDA receptor antagonist and antiviral agent. This interaction is proposed to occur via competitive inhibition of renal tubular secretion mediated by organic cation transporters (OCTs) present in the proximal tubule, leading to reduced amantadine clearance. Clinically, elevated amantadine levels can precipitate dose-related adverse effects including confusion, hallucinations, orthostatic hypotension, and peripheral edema, particularly in elderly patients or those with pre-existing renal impairment."
"Anagrelide is a phosphodiesterase 3 (PDE3) inhibitor with dose-dependent QT interval prolongation risk due to inhibition of the hERG potassium channel. Amantadine, a dopamine agonist and antiviral agent, also has mild QTc-prolonging properties, possibly through direct myocardial ion channel effects. Concomitant use may result in additive QT interval prolongation, increasing the risk of torsade de pointes and other ventricular arrhythmias."
"Amantadine, an antiviral and antiparkinsonian agent with weak NMDA receptor antagonist properties, may reduce the antipsychotic efficacy of mesoridazine, a phenothiazine antipsychotic. This interaction likely occurs via pharmacodynamic opposition, where amantadine's dopaminergic activity counteracts mesoridazine's dopamine receptor blockade in the central nervous system. Clinically, this can lead to worsening of psychotic symptoms or reduced therapeutic response to mesoridazine."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about AMANTADINE vs ACTIQ, answered by our medical review team.
AMANTADINE is a Antiviral / Antiparkinsonian that works by Amantadine is an antiviral and antiparkinsonian agent. Its antiviral mechanism involves inhibition of viral uncoating, thereby blocking influenza A M2 ion channel. In Parkinson's disease, it is thought to increase dopamine release and inhibit its reuptake, and may also have anticholinergic and NMDA receptor antagonist effects.. ACTIQ is a Opioid Analgesic that works by Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between AMANTADINE and ACTIQ depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of AMANTADINE is: 100 mg orally twice daily for Parkinson's disease; 100 mg orally twice daily for influenza A prophylaxis/treatment (up to 200 mg/day).. The standard adult dose of ACTIQ is: 200 mcg transmucosally, titrated upward as needed; initial dose for opioid-tolerant patients is 200 mcg, with additional doses possible after 15 minutes if needed. Maximum 4 doses per episode. At least 4 hours between episodes.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between AMANTADINE and ACTIQ in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. AMANTADINE is classified as Category C. FDA Pregnancy Category C. First trimester: Associated with cardiovascular malformations (e.g., Ebstein anomaly) in retrospective studies; risk approximately 1-2% absolute. Second a. ACTIQ is classified as Category C. FDA Pregnancy Category C. First trimester: limited human data; animal studies show increased resorptions and fetal growth restriction. Second/third trimester: chronic use may cause. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.