26
Treatment
Medications for treatment of medication-induced
parkinsonism
a
Genric name
Trade name
Amantadine
Symmetrel
Benztropine mesylate
Cogentin
Typical use Parkinsonism Acute dystonia,
parkinsonism
Mechanism of action Uncompetitive NMDA
receptor antagonist
(weak)
Muscarinic antagonist
Available formulations
(mg, unless otherwise
noted)
Tablet: 100
Tablet, extended release:
129, 193, 258
Capsule: 100
Capsule, liquid filled:
100
Capsule, extended
release: 68.5, 137
Oral syrup: 50/5 mL
Tablet: 0.5, 1, 2
Solution, injection: 1/mL
(2 mL)
Typical dose range
(mg/day)
Immediate release
tablet or capsule:
100–300
Extended release tablet:
129–322
Tablet: 0.5–6.0
Solution, injection: 1–2
Bioavailability 86%–94% 29%
Time to peak level
(hours)
Immediate release: 2–4
Extended release: 7.5–12
Oral: 7
IM: minutes
Protein binding 67% 95%
Metabolism Primarily renal Hepatic
Metabolic enzymes/
transporters
Substrate of organic
cation transporter 2
Substrate of CYP2D6
(minor)
Metabolites Multiple; unknown
activity
Not known
Elimination half-life
(hours)
16–17 7
Excretion Urine 85% unchanged;
0.6% fecal
Urine
Hepatic impairment No dose adjustments
noted in labeling
No dose adjustments
noted in labeling
