Comparative Pharmacology
Head-to-head clinical analysis: AMANTADINE versus SYMADINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: AMANTADINE versus SYMADINE.
AMANTADINE vs SYMADINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
SYMADINE (amantadine) is a tricyclic amine that inhibits influenza A virus replication by blocking the viral M2 ion channel, which prevents uncoating of viral RNA. It also increases dopamine release and inhibits dopamine reuptake in the CNS, providing antiparkinsonian effects.
100 mg orally twice daily for Parkinson's disease; 100 mg orally twice daily for influenza A prophylaxis/treatment (up to 200 mg/day).
100 mg orally every 12 hours; immediate-release formulation.
None Documented
None Documented
Clinical Note
moderateAmantadine + Haloperidol
"The therapeutic efficacy of Haloperidol can be decreased when used in combination with Amantadine."
Clinical Note
moderateAmantadine + Mifepristone
"Amantadine may increase the QTc-prolonging activities of Mifepristone."
Clinical Note
moderateAmantadine + Promazine
"The therapeutic efficacy of Promazine can be decreased when used in combination with Amantadine."
Clinical Note
moderateAmantadine + Chlorpromazine
Terminal elimination half-life: 10-14 hours in young adults, up to 24 hours in elderly; prolonged to >24 hours in renal impairment
The terminal elimination half-life is approximately 24 hours in patients with normal renal function. In patients with renal impairment (CrCl <50 mL/min), the half-life is significantly prolonged, requiring dose adjustment. The long half-life allows for once-daily dosing.
Renal: 90% as unchanged drug via glomerular filtration and tubular secretion; fecal: <10%
Renal elimination of unchanged drug accounts for approximately 90% of the administered dose. Biliary/fecal excretion is minimal (<5%).
Category C
Category C
Antiviral / Antiparkinsonian
Antiviral and Antiparkinsonian
"The therapeutic efficacy of Chlorpromazine can be decreased when used in combination with Amantadine."