Pharmacology II Exam II - Chapter 15 Parkinson's Drugs

What is the primary problem with Parkinson's?

Insufficient dopamine (inhibitory CNS neurotransmitter).

ropinorole (Requip) drug interactions

Interacts with warfarin/Coumadin - if taken together you can end up with toxic levels of ropinorole (Requip).

What happens when levodopa is no longer effective by itself?

Levadopa is then formulated with carbidopa to decrease the amount of drug needed for effect. The combo drug is called sinemet.

Levodopa drug interactions:

May interact with antipsychotics, non-selective MAOIs, and benzodiazepines.

benztropine (Cogentin) nursing considerations

Monitor for anticholinergic side effects. Use with caution in hot weather - may cause hyperthermia

ropinorole (Requip)

More specific for D2 dopamine receptors. Delays the need for levodopa.

tolcapone (Tasmar) nursing considerations

Must monitor liver functions. Can cause urine to darken. Do not take with non-selective MAOI's.

Does dopamine cross the blood brain barrier?

No.

2. What is a dopamine mimicking drug?

Non-dopamine drugs that act like dopamine at the receptor sites. (non-dopamine receptor agonists)

selegiline (Eldepryl)

PO

bromocriptine

Parlodel

entacapone (Comtan)

Peripherally acting COMT inhibitor. Inhibits the breakdown of levodopa, leaving more active drug.

tolcapone (Tasmar)

Peripherally and centrally acting COMT inhibitor. Not usually given due to severe liver side effects.

3. Drugs that increase the release of dopamine:

Presynaptic dopamine release enhancer. Must still have dopamine producing cells. amandatine (Symmetrel)

ropinorole

Requip

4. Drugs that selectively inhibit breakdown of dopamine

Selective MAOB inhibitors. Will not affect your heart the same way non-selective MAOB inhibitors will.

benztropine (Cogentin) dose forms

Tablets or injectable

Nursing considerations for dopamine replacement drugs (levodopa) are:

Taken multiple times a day (3-4x) May take 3-4 weeks for effects Increase fluids and fiber (prevent constipation) Limit amount of high protein foods Take 30 minutes prior to meal

selegiline (Emsam)

Transdermal

What is sinemet?

Combo drug levodopa with carbidopa added to it.

What is 1st line dopamine replacement drug?

levadopa

Nonergot drugs

ropinorole (Requip)

What is 2nd line dopamine replacement drug?

sinemet

What are the 6 classifications of drugs that treat Parkinson's?

1. Dopamine replacement drugs 2. Dopamine mimicking drug 3. Drugs that increase release of dopamine 4. Drugs that inhibit the breakdown of dopamine 5. Drugs that inhibit COMT breakdown of catacholamines 6. Drugs that block Acetylcholine (excitatory CNS neurotransmitter) effects from imbalance

resigiline (Azilect) levels for MAOB selectivity:

< 10 mg

resigiline (Azilect) levels for MAOB non-selectivity:

> 10 mg

What can happen with ongoing use of levadopa?

A "drug holiday" may be needed. Another anti-Parkinson's drug can be used during this time off.

5. Drugs that inhibit COMT breakdown of catacholamines:

COMT inhibitors "capone" entacapone (Comtan) Tolcapone (Tasmar)

benztropine (Cogentin)

Anticholinergic drug that treats the s/s of Parkinson's Dries everything up and slows everything down Increase fluids and fibers

6. Drugs that block the effect of Acetylcholine

Anticholinergics benztropine (Cogentin)

amandatine (Symmetrel)

Antiviral drug used to control Parkinson's symptoms

bromocriptine (Parlodel) warnings

Causes vasoconstriction - do NOT use in patients with PVD (venous or arterial disease)

What are the S/E of dopamine replacement drugs (levodopa)?

Both central and peripheral including: mydriasis (dilated pupils), HTN, anxiety, nausea, vomiting, hallucinations, sedation.

selegiline (Zelapar)

Buccal

amandatine (Symmetrel) s/e

Dizziness, insomnia, nausea

tolcapone (Tasmar) contraindications

Do not give in patient with liver disease. Must monitor liver functions.

bromocriptine (Parlodel) nursing considerations

Do not take with food. Causes vasoconstriction - monitor HR, BP

entacapone (Comtan) nursing considerations:

Do not take with non-selective MAOI's Take with food. May darken urine.

Why is entacapone (Comtan) used with levodopa?

Draws out therapeutic effects of levodopa. Decreases on-off effect.

What is COMT?

Enzyme that degrades catecholamines (dopamine, epinephrine and norepinephrine).

Non-dopamine receptor agonists:

Ergot derivatives - bromocriptine (Parlodel) Nonergot drugs - ropinorole (Requip)

Why should dopamine replacement drugs (levodopa) be taken 30 minutes prior to meal?

Food may interfere with levodopa uptake in the brain.

tolcapone (Tasmar) severe adverse effect

Fulminating hepatic necrosis (acute liver failure where there was not liver failure before)

bromocriptine (Parlodel) indications

Used for "off" periods of levodopa in treatment of Parkinson's. Also used as adjunct antidiabetic to lower blood sugar

resigiline (Azilect)

Used to reduce needed dose of levodopa

benztropine (Cogentin) mechanism of action

Will dry up secretions - otherwise not usually given.

What happens if you give levodopa with non-selective MAOI's?

Will have a hypertensive crisis.

Ergot derivatives

bromocriptine (Parlodel)