Chapter 21: Drugs for Parkinson's Disease

A nurse is teaching a group of nurses about Parkinson's medications. The nurse is correct to state that one side effect associated with pramipexole [Mirapex] that is less likely to occur with other dopamine agonists is: a.sleep attacks. b.dizziness. c.hallucinations. d.dyskinesias

ANS: A A few patients taking pramipexole have experienced sleep attacks, or an overwhelming and irresistible sleepiness that comes on without warning. Dizziness, hallucinations, and dyskinesias are listed as side effects of pramipexole and other dopamine agonists.

A nurse is discussing motor symptoms with a patient with Parkinson's disease who has been taking levodopa/carbidopa [Sinemet] for 9 months and who is now having regular tics. Which statement by the patient indicates understanding of this symptom? a."I may need to try a lower dose of Sinemet to reduce my tics." b."My provider may order clozapine to treat these tics." c."These tics are an indication that my dose of Sinemet is too low." d."This means I will have to have surgery to stop the symptoms."

ANS: A Levodopa can cause movement disorders, generally within the first year of therapy. If they occur, a lower dose of levodopa may be required to alleviate them. Clozapine is an antipsychotic used to treat levodopa-induced psychoses. Movement disorders generally occur as the dose of levodopa increases. Surgery is a last option for treating movement disorders, after amantadine fails.

A nurse provides teaching for a patient who is newly diagnosed with Parkinson's disease. Which statement by the patient indicates understanding of the drug therapy for this disease? a."A levodopa/carbidopa combination is used to improve motor function." b."There are several drugs available to treat dyskinesias." c."When 'off' times occur, I may need to increase my dose of levodopa." d."With adequate drug therapy, the disease progression may be slowed."

ANS: A Levodopa combined with carbidopa is the initial drug of choice to treat motor symptoms. Amantadine is the only drug recommended to treat dyskinesias. Entacapone and rasagiline are used to treat abrupt loss of effect, or "off" times. Drug therapy does not slow the progression of the disease.

A 25-year-old patient has been newly diagnosed with Parkinson's disease, and the prescriber is considering using pramipexole [Mirapex]. Before beginning therapy with this drug, the nurse will ask the patient about: a.any history of alcohol abuse or compulsive behaviors. b.any previous history of hypertension. c.difficulty falling asleep or staying asleep. d.whether any family members have experienced psychoses.

ANS: A Pramipexole has been associated with impulse control disorders, and this risk increases in patients with a history of alcohol abuse or compulsive behaviors. Pramipexole increases the risk of hypotension and sleep attacks, so a history of hypertension or insomnia would not be cautionary. Unlike with levodopa, the risk of psychoses is not increased.

A patient with Parkinson's disease is taking levodopa/carbidopa [Sinemet] and reports occasional periods of loss of drug effect lasting from minutes to several hours. The nurse questions the patient further and discovers that these episodes occur at different times related to the medication administration. The nurse will contact the provider to discuss: a.administering a catechol-O-methyltransferase (COMT) inhibitor, such as entacapone. b.adding the DA-releasing agent amantadine to the regimen. c.giving a direct-acting dopamine agonist. d.shortening the dosing interval of levodopa/carbidopa

ANS: A This patient is describing abrupt loss of effect, or the "off" phenomenon, which is treated with entacapone or another COMT inhibitor. Amantadine is used to treat dyskinesias. A direct-acting dopamine agonist is useful for gradual loss of effect, which occurs at the end of the dosing interval as the dose is wearing off. Shortening the dosing interval does not help with abrupt loss of effect.

A nursing student wants to know how carbidopa can be effective for treating Parkinson's disease if it prevents the conversion of levodopa to dopamine. The nurse explains that carbidopa: a.can be taken with high-protein meals. b.does not cross the blood-brain barrier. c.has dopamine-like effects of its own. d.reduces abrupt loss of effect.

ANS: B Carbidopa inhibits decarboxylation of levodopa in the intestine and peripheral tissues, leading to more levodopa in the CNS. Carbidopa cannot cross the blood-brain barrier, so it does not have this action in the CNS. Carbidopa is not given with high-protein meals. Carbidopa does not have dopamine-like effects. Carbidopa does not affect abrupt loss of effect.

The nurse provides teaching for a patient who will begin taking rotigotine [Neupro] to treat Parkinson's disease. What will the nurse include in teaching? a."If you develop nausea and vomiting, you should stop taking the medication." b."If you need to stop this drug, your provider will order a gradual withdrawal." c."You will start this drug regimen with a higher than usual loading dose." d."You will take this medication by mouth with food."

ANS: B Rotigotine is a nonergot dopamine agonist, which is given by starting with a 2-mg dose that is increased by 2 mg each week until the lowest effective dose is reached. It should not be stopped abruptly but should be decreased by 2 mg per week until tapered off. It undergoes extensive first-pass metabolism, so it is not given orally and is currently available as a transdermal patch

A patient with Parkinson's disease is taking levodopa/carbidopa [Sinemet] along with amantadine [Symmetrel] 400 mg/day to treat dyskinesias. The patient reports having increased dyskinesias several months after beginning the amantadine. The nurse will contact the provider to discuss which action? a.Increasing the dose of amantadine [Symmetrel] b.Interrupting treatment with amantadine for several weeks c.Ordering renal function tests d.Ordering another anticholinergic medication

ANS: B When amantadine is added to therapy to treat dyskinesias associated with levodopa, it often loses effectiveness after several months. If the effects diminish, they can be restored by either increasing the dosage or by interrupting treatment for several weeks. The maximum dosage of amantadine is 400 mg/day, so it is incorrect to increase the dose. Altered renal function would result in drug toxicity, not ineffectiveness of the drug. It is not necessary to order another drug until determining whether the effectiveness can be restored.

A patient has taken levodopa [Dopar] for Parkinson's disease for 2 weeks but reports no improvement in the symptoms. Which response by the nurse is correct? a."Another agent will be needed to manage your symptoms." b."Double the dose to see whether an effect occurs." c."It may take several months for a response to occur." d."The prescriber may need to change your drug regimen."

ANS: C A full therapeutic response with levodopa may take several months to develop. Until the true effect of the dose is seen, it is not necessary to change to another drug, increase the dose, or change the drug regimen

A patient newly diagnosed with Parkinson's disease has been taking levodopa/carbidopa [Sinemet] for several weeks and complains of nausea and vomiting. The nurse tells the patient to discuss what with the provider? a.Taking a lower dose on an empty stomach b.Taking an increased dose along with a high-protein snack c.Taking a lower dose with a low-protein snack d.Taking dopamine in addition to levodopa/carbidopa

ANS: C Because levodopa activates the chemoreceptive trigger zone (CTZ) of the medulla, causing nausea and vomiting (N/V), the patient may need to take a lower dose temporarily until tolerance develops. A meal helps slow absorption to minimize this side effect. A high protein intake contributes to abrupt loss of effect, so meals should be low in protein. Taking a dose on an empty stomach increases absorption and also N/V. An increased dose with a high-protein snack increases N/V and also abrupt loss of effect. Dopamine increases N/V, because it activates the CTZ of the medulla.

A patient with Parkinson's disease is taking levodopa/carbidopa [Sinemet]. The prescriber orders bromocriptine [Parlodel] to treat dyskinesias. The nurse notes that the patient is agitated, and the patient reports having frequent nightmares. The nurse will contact the provider to discuss: a.adding an antipsychotic medication. b.changing from bromocriptine to cabergoline [Dostinex]. c.reducing the dose of bromocriptine. d.reducing the dose of levodopa/carbidopa.

ANS: C Bromocriptine is used to treat levodopa-induced dyskinesias and has dose-dependent psychologic side effects. The nurse should suggest reducing the dose of this drug to minimize these side effects. Adding an antipsychotic medication is not indicated. Cabergoline is not approved for this use. Reducing the dose of levodopa/carbidopa is not indicated.

A patient who has begun taking levodopa/carbidopa [Sinemet] reports feeling lightheaded and dizzy, especially when standing up from a sitting position. What will the nurse recommend? a.An alpha-adrenergic antagonist medication b.Discussing amantadine with the prescriber c.Increasing salt and water intake d.Taking a drug holiday

ANS: C Postural hypotension is common early in treatment and can be reduced by increasing the intake of salt and water. An alpha-adrenergic agonist, not an antagonist, can help. Amantadine is used to treat levodopa-induced dyskinesias. Drug holidays are used when adverse effects increase with long-term use of levodopa; the drug holiday allows beneficial effects to be achieved with lower doses, which reduces the incidence of side effects.

A nursing student wants to know why a patient who has been taking levodopa [Dopar] for years will now receive levodopa/carbidopa [Sinemet]. The nurse explains the reasons that levodopa as a single agent is no longer available. Which statement by the student indicates a need for further education? a."Carbidopa increases the availability of levodopa in the central nervous system." b."Carbidopa reduces the incidence of nausea and vomiting." c."Combination products reduce peripheral cardiovascular side effects." d."Combination products cause fewer dyskinesias and decreased psychosis."

ANS: D Adding carbidopa to levodopa does not reduce the incidence of dyskinesias or psychosis. In fact, carbidopa can increase the intensity and the speed of onset of these effects. Carbidopa inhibits decarboxylation of levodopa in the intestine and peripheral tissues, leading to more levodopa in the CNS. Carbidopa cannot cross the blood-brain barrier, so it does not have this action in the CNS. Peripheral side effects are reduced, including nausea, vomiting, and cardiovascular effects.

A patient has been diagnosed with Parkinson's disease (PD) and begins treatment with levodopa/carbidopa [Sinemet]. After several months of therapy, the patient reports no change in symptoms. The nurse will expect the provider to: a.add a dopamine agonist. b.discuss the "on-off" phenomenon. c.increase the dose of Sinemet. d.re-evaluate the diagnosis

ANS: D Patients beginning therapy with levodopa/carbidopa should expect therapeutic effects to occur after several months of treatment. Levodopa is so effective that a diagnosis of PD should be questioned if the patient fails to respond in this time frame. Adding a dopamine agonist is not indicated. The "on-off" phenomenon occurs when therapeutic effects are present. Increasing the dose of levodopa/carbidopa is not indicated.

A patient who is newly diagnosed with Parkinson's disease is prescribed levodopa [Dopar]. The patient asks the nurse about drugs to prevent disease progression. What will the nurse tell this patient? a."Levodopa may prevent disease progression in higher doses and is safe to use for this purpose." b."MAO-B inhibitors and dopamine agonists have both shown neuroprotective effects in human studies." c."Vitamin E has been shown to delay neuron degeneration and may be used as adjunctive therapy." d."While some drugs show promise, there are no studies that have proven a neuroprotective effect."

ANS: D To date, there is no definitive proof that any drug can protect dopaminergic neurons from progressive degeneration. Levodopa has shown neuroprotective effects, but studies have demonstrated toxic effects in the doses required for this purpose. MAO-B inhibitors have shown benefits, but only in animal studies. Vitamin E was once theorized to offer this protection, but recent studies have provided good evidence that this is not the case.

A hospitalized patient with Parkinson's disease who is receiving apomorphine to treat "off" episodes develops nausea and vomiting. The nurse will discuss the use of which medication with the patient's provider? a.Levodopa [Dopar] b.Ondansetron [Zofran] c.Prochlorperazine [Compazine] d.Trimethobenzamide [Tigan]

ANS: D Trimethobenzamide can be used as an antiemetic in patients treated with apomorphine. Serotonin receptor agonists (eg, ondansetron) and dopamine receptor antagonists (eg, prochlorperazine) cannot be used, because they increase the risk of serious postural hypotension. Levodopa only increases nausea and vomiting.