Chapter 47: Drug Therapy for Parkinson's Disease and Anticholinergics

akinesia

rigid limbs

Tolcapone (Tasmar)

-COMT inhibitor -purpose is to inhibit the metabolism of levodopa in the bloodstream, increasing plasma concentration and duration of action of the drug ADMINSTRATION: PO -> MAOI's -> hypertensive risk *levodopa ADVERSE EFFECTS -disorientations, confusion, hallucinations, psychosis, dizziness, othostatic hypotension BLACK BOX WARNING: -liver failure CONTRAINDICATION: -renal failure, pregnancy, breastfeeding

Levodopa, Carbidopa and Entacapone (Stalevo)

-reversible and selective inhibitor of COMT -> alters levodopa, allows for more sustained levodopa serum levels, increase concentrations for absorption ADMINISTRATION: PO ADVERSE EFFECTS: GI -> diarrhea, nausea, vomiting, excessive teeth clenching, dry mouth, excess salivation CV -> hypotension, heart attack, stroke, and cardiovascular death CONTRAINDICATIONS: sensitivity, MAOI use, melanoma, pleural effusion

Levodopa/ Carbidopa (Sinemet)

-well established as the most effective drug for the symptomatic treatment of idiopathic Parkinson's disease -levodopa -> metabolized in peripheral tissues, large doses are required to obtain therapeutic levels of dopamine in the brain -carbidopa -> help reduce the levodopa dosage and decrease adverse effects, decrease the peripheral metabolism of Levodopa ADMINSTRATION: PO -cannot be administered with a high-protein diet. avoid alcohol ADVERSE EFFECTS -CNS -> headache and anxiety, hallucinations, dementia and drowsiness -CV -> ectopic beats, tachycardia, agina pain, palpitation, hypotension, vasoconstriction, dyspnea, bradycardia, widening QRS waves -dermatologic effects -> hypersensitivity, anaphylaxis CONTRAINDICATIONS: -drugs can dilate pupils -> narrow-angle glaucoma -activate malignant melanoma -MAOI's, tricyclic antidepressants THERAPEUTIC EFFECTS: observes improvement in mobility, balance, posture, gait, speech, handwriting and self-care ability

Atropine Sulfate

ANTIDOTE FOR CHOLINERGICS anti-cholinergic drug that blocks the effects of acetylcholine at muscarinic cholinergic receptors -crosses the BBB -used to relieve tremors and decrease rigidity -helps with the restoration of cardiac rate and arterial pressure when the vagal response is stimulated -tertiary amine ADVERSE EFFCECTS: -tachycardia (high doses), blurred vision, mydriasis, cycloplegia, photophobia, increased intraocular pressure, paralytic ileus, urinary hesitancy and retention CONTRAINDICATIONS: do not give to people with myansethia gravis, impaired renal or hepatic function OVERDOSE -> presentation of hyperthermia

Dicyclomine hydrochloride (Bentyl)

GI anticholinergic medication -GI smooth muscle relaxant -> blocks the effects of acetylcholine at muscarinic cholinergic receptors -IRRITABLE BOWEL SYNDROME ADMINSTRATION: PO and parenteral -patient has to void before administering ADVERSE EFFECTS: blurred vision, dry mouth, altered taste perception, nausea, vomiting, dysphagia, urinary hesitancy, urinary retention, irritation at injection site CONTRAINIDICATIONS: hypersensitivity, glaucoma, some ulcers, bronchial asthma, urinary bladder neck obstruction, hepatic or renal disease, GI obstruction, myasthenia gravis, prostatic hypertrophy THERAPEUTIC EFFECTS: decrease in abdominal pain

Oxybutynin (Ditropan)

anticholinergic drug that is a urinary antispasmodic, relieves symptoms of urinary incontinence and frequency that accompany an overactive bladder -inhibits effects of acetylcholine at muscarinic receptors ADMINSTRATION: PO, transdermal ADVERSE EFFECTS: drowsiness, dizziness, blurred vision, dry mouth, nausea, urinary hesitancy, decreased sweating CONTRAINDICATIONS: hypersensitivity, pyloric or duodenal ulcer, obstructive intestinal lesions, intestinal atony, megacolon, colitits, obstructive uropathies, glaucoma, cardiovascular instability, urinary retention THERAPEUTIC EFFECTS: decreased urinary incontinence, urgency and frequency

basal ganglia

area in the midbrain that controls smooth voluntary movement

bradykinesia

inability to move

benzotropinemesylate (Cogentin)

centrally acting anticholinergic -drugs help normalize the imbalance of cholinergic and dominergic neurotransmission in the basal ganglia of the brain to reduce rigidity, akinesia and tremor -reduces secondary symptoms of parkinsonism -> excessive salivary secretions and drooling -adjunctive therapy ADMINISTRATION: PO and parenterally *administer with food* ADVERSE EFFECTS: CNS -> disorientation, confusion, hallucinations, memory loss, psychoses, agitation, euphoria, light-headedness, depression giddiness and heaviness of limbs -tachycardia, palpitations, hypotension, orthostatic hypotension, blurred vision, dry mouth, urinary retention, decreased sweating and elevated temperature CONTRAINDICATIONS: -glaucoma -> drug increases intraocular pressure -GI obstruction, myasthenia gravis -Caution -> cardiovascular disorders -> tachycardia, dysrhythmias, hypertension *AVOID OVERHEATING -> drink water frequently* THERAPEUTIC EFFECTS: decreased rigidity and tremor, assess for a decrease in oral secretions

anticholinergic drugs

drug that inhibits the actions of acetylcholine in the brain

antimuscarinic drug

drug that interacts with muscarinic cholinergic receptors in the brain, secretory glands, heart, and smooth muscle to produce an anticholinergic response