Antiparkinson Drugs

Antiparkinson Drugs

Levodopa/Carbidopa (Sinemet)
(L-Dopa; Larodopa, Dopar)

Levodopa is decarboxylated to dopamine in both and peripheral tissues. By adding Carbidopa a peripheral decarboxylase inhibitor=More levodopa enters the brain and is converted into DA in brain
Short half-life 3 or more doses
Short Term-N/V (Phenergan), ortho HypoTN, palpitation, arrhythmias, CNS changes (compulsive behaviors), Sleep Attacks, Blepharospams, dyskinesia
Long Term—End dose phenomena, On-Off phenomena, 2nd levodopa failure

DIET HIGH IN PROTEIN OR VIT B-6; cardiac stimulants, anti-HTN drugs; HTN crisis with MAOIs; ↓seizure threshold; ↑ICP in glaucoma pt DIET HIGH IN PROTEIN OR VIT B-6; cardiac stimulants, anti-HTN drugs; HTN crisis with MAOIs; ↓seizure threshold; ↑ICP in glaucoma pt
Pramipexole (Mirapex)
Ropinirole (Requip)
Apomorphine (Apokyn)

Requip—Restless leg syndrome
Direct agonist for dopamine receptors in EPS; non-ergot dopamine agonist at dopamine receptorsN, somnolence, BLE edema, postural HypoTN, confusion, (do not use old dementia pt), impulse control disorder; hallucinations, confusion, dyskinesia, nightmares, drowsiness, Sleep AttacksPsychiatric illness can ↑ mental condition
Serious cardiac problems esp. in pts with HTx of MI, PVD
Bromocriptine is an Ergot derivate that can ↑ pulm &retroperitoneal fibrosis (severe)
Requip: non-ergotamine derivative with ↓ cardiac, pulm, GI (SEs) but→↑ psychosis,(compulsive behavior)
Apokyn: treat episode of immobility; Drug is give SQ, causes severe emesis give Trimethobenzamide (tigan) bc Zofran can cause HypoTN and ↓LOC
Hypersexuality and increased erection can occur
Tolcapone (Tasmar)
Entacapone (Comtan)

Comtan is derived from the enzyme Catechol-o-methyltransferase = peripheral breakdown of levodopa. It inhibits the breakdown of DA in the peripheral =↑DA level
Inhibition of COMT leads to ↓ concentration of a by-product (3-O-methyldopa) that competes with levodopa for active transport into the CNS with the use of Carbidopa
This agent prolongs the dopamine that you will have available
N/V/D, postural hypoTN, dyskinesia, hallucinations, sleep disordersTolcapone (Tasmar) has been associated with hepatotoxicity (hepatic monitor 2X per mt for 1st 6 mt) TAKEN OFF MARKET Add on agent bc not supplying any DA

Has a short half-life and must be taken with each dose of levodopa
MAO-B Inhibitors
Selegiline (Eldepryl)
Rasagiline (Azilect)

A selective inhibitors of MAO-B enzyme(which metabolizes DA) → ↑ DA levels in the brain as a result ↑efficacy of levodopa when given togetherNausea, ortho hypoTN, insomnia
Exceeding 10mg/day can cause severe HTN “cheese effect”
Meperdine(Demerol) and Fluoxetine (Prozac) are CI
Other ODTs—Dilaudid, methadone, Propoxyphene (Darvon), tramadol
Metabolizes to an amphetamine—give in AM
Benzotropine (Cogentin)
Trihexyphenidyl (Artane)
Procyclidine (Kemadrin)
Biperiden (Akineton
↓the excitatory effects of acetylcholine(central)↔better balance between DA and Acetylcholine—reduced tremors and muscle rigidityDry mouth, constipation, urinary retention, Anti SLUDGE; Mydriatic effect= ↑glaucoma
CNS—impaired memory, confusion, hallucination
Strict dose adjustmt in old bc of anticholinergic effects
Glaucoma, stenosing peptic ulcer, BPH or bladder neck obstruction, Achalasia, myasthenia gravis, megacolonDDI: Amantadine (Symmetrel), other anticholinergic , MAOIs, Digoxin, Haloperidol, Levodopa (↓levodopa activity from ↓GI motility)
Phenothiazine (↑antichol effects)
Glutamate Antagonist
Amantadine (Symmetrel)↑DA from neurons (antagonist) , may also block reuptake of DA, block cholinergic activity (anticholinergic activity)drowsiness, confusion most common; N, dizzy, confusion, some anticholinergic SE; Potential Psychosis in old; ↓seizure threshold; ankle edema Livedo reticularis of the legs w/wo cardiac failure (purple rash)Anticholinergic may have an additive effect on mental function Sudden withdraw can cause ↑ Parkinson symptoms or neuroleptic malignant syndrome (acute delirium)

Monitor Liver FXN