"The US Food and Drug Administration (FDA) has approved pimavanserin tablets (Nuplazid, Acadia Pharmaceuticals) for the treatment of hallucinations and delusions associated with psychosis in Parkinson's disease (PD).
The following adverse reactions are discussed in more detail in the WARNINGS AND PRECAUTIONS sections of labeling:
- Falling Asleep During Activities of Daily Living and Somnolence [see WARNINGS AND PRECAUTIONS]
- Hypotension/Orthostatic Hypotension and Syncope [see WARNINGS AND PRECAUTIONS]
- Dyskinesia [see WARNINGS AND PRECAUTIONS]
- Depression and suicidality [see WARNINGS AND PRECAUTIONS]
- Hallucinations/Psychotic-Like Behavior [see WARNINGS AND PRECAUTIONS]
- Impulse Control and/or Compulsive Behaviors [see WARNINGS AND PRECAUTIONS]
- Withdrawal-Emergent Hyperpyrexia and Confusion [see WARNINGS AND PRECAUTIONS]
- Diarrhea and Colitis [see WARNINGS AND PRECAUTIONS]
- Rhabdomyolysis [see WARNINGS AND PRECAUTIONS]
- Peptic Ulcer Disease [see WARNINGS AND PRECAUTIONS]
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, the incidence of adverse reactions (number of unique patients experiencing an adverse reaction associated with treatment/total number of patients treated) observed in the clinical trials of a drug cannot be directly compared to the incidence of adverse reactions in the clinical trials of another drug and may not reflect the incidence of adverse reactions observed in clinical practice.
The most commonly observed adverse reactions (incidence at least 3% greater than placebo incidence) in the double-blind, carbidopa-levodopa-placebo-controlled trials of entacapone (N=1,003 patients) associated with the use of carbidopa-levodopa-entacapone alone and not seen at an equivalent frequency among the placebo-treated patients were: dyskinesia, urine discoloration, diarrhea, nausea, hyperkinesia, vomiting, and dry mouth.
The treatment difference incidence for premature study discontinuation for entacapone with levodopa and dopa decarboxylase inhibitor in the double-blind, placebo-controlled trials was 5%. The treatment difference incidence for the most frequent causes of study discontinuation was 2% for diarrhea, and 1% for other specific adverse reactions including psychiatric reasons, dyskinesia/ hyperkinesia, nausea, or abdominal pain.
Adverse Reaction Incidence in Controlled Clinical Studies of Entacapone
Table 2 lists treatment emergent adverse reactions that occurred in at least 1% of patients treated with carbidopa/levodopa and 200 mg of entacapone who participated in the double-blind, placebo-controlled studies, and that were numerically more common in this group than in the carbidopa/levodopa plus placebo group. In these studies, either entacapone or placebo was added to carbidopa/levodopa (or benserazide/levodopa).
Table 2: Summary of Patients With Adverse Reactions
After Start of Trial Drug Administration At Least 1% in Entacapone Group and
Greater Than Placebo
|SYSTEM ORGAN CLASS
|Carbidopa/levodopa plus Entacapone
(n=603) % of patients
|Carbidopa/levodopa plus Placebo
(n=400) % of patients
|SKIN AND APPENDAGES DISORDERS|
|MUSCULOSKELETAL SYSTEM DISORDERS|
|CENTRAL AND PERIPHERAL NERVOUS SYSTEM DISORDERS|
|SPECIAL SENSES, OTHER DISORDERS|
|GASTROINTESTINAL SYSTEM DISORDERS|
|Gastrointestinal Disorders NOS||1||0|
|RESPIRATORY SYSTEM DISORDERS|
|PLATELET, BLEEDING AND CLOTTING DISORDERS|
|URINARY SYSTEM DISORDERS|
|BODY AS A WHOLE-GENERAL DISORDERS|
|RESISTANCE MECHANISM DISORDERS|
The following spontaneous reports of adverse events temporally associated with entacapone or Stalevo have been identified since market introduction and are not listed in Table 2. Because these reactions are reported voluntarily from a population of unknown size, it is not always possible to reliably estimate their frequency or establish causal relationship to entacapone or Stalevo exposure.
Hepatitis with mainly cholestatic features has been reported.
Effects of Gender and Age on Adverse Reactions
No differences were noted in the rate of adverse reactions attributable to entacapone alone by age or gender.
Read the Stalevo (carbidopa, levodopa and entacapone) Side Effects Center for a complete guide to possible side effects
Patients receiving nonselective MAO inhibitors and carbidopa, levodopa and entacapone may be at risk of increased adrenergic tone. Therefore, the use of Stalevo is contraindicated in patients receiving nonselective MAO inhibitors [see CONTRAINDICATIONS].
Drugs Metabolized By Catechol-O-Methyltransferase (COMT)
Drugs known to be metabolized by COMT, such as isoproterenol, epinephrine, norepinephrine, dopamine, dobutamine, alpha-methyldopa, apomorphine, isoetherine, and bitolterol should be administered with caution in patients receiving entacapone regardless of the route of administration (including inhalation), as their interaction may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure [see WARNINGS AND PRECAUTIONS].
Symptomatic postural hypotension has occurred when carbidopa/levodopa was added to the treatment of patients receiving antihypertensive drugs. When starting therapy with Stalevo, dosage adjustment of antihypertensive drug may be required.
There have been reports of adverse reactions, including hypertension and dyskinesia, resulting from the concomitant use of tricyclic antidepressants and carbidopa/levodopa.
Dopamine D2 Receptor Antagonists
Dopamine D2 receptor antagonists (e.g., metoclopramide, phenothiazines, butyrophenones, risperidone) may reduce the therapeutic effects of levodopa.
Isoniazid may reduce the therapeutic effects of levodopa, a dose increase may be necessary.
The beneficial effects of levodopa in Parkinson's disease have been reported to be reversed by phenytoin. Patients taking phenytoin with carbidopa/levodopa should be carefully observed for loss of therapeutic response. Stalevo dosage should be increased as clinically needed in patients receiving phenytoin.
The beneficial effects of levodopa in Parkinson's disease have been reported to be reversed by papaverine. Patients taking papaverine with carbidopa/levodopa should be carefully observed for loss of therapeutic response. Stalevo dosage should be increased as clinically needed in patients receiving papaverine.
Iron salts or multi vitamins containing iron salts should be coadministered with caution. Iron salts can form chelates with levodopa, carbidopa and entacapone and consequently reduce bioavailability of levodopa, carbidopa and entacapone.
Drugs Known To Interfere With Biliary Excretion, Glucuronidation, And Intestinal Beta-glucuronidase
As most entacapone excretion is via the bile, caution should be exercised when drugs known to interfere with biliary excretion, glucuronidation, and intestinal beta-glucuronidase are given concurrently with entacapone. These include probenecid, cholestyramine, and some antibiotics (e.g., erythromycin, rifampicin, ampicillin and chloramphenicol).
Drugs Metabolized via CYP2C9 (e.g., coumadin)
The dosage of Stalevo should be adjusted as clinically needed in patients using other drugs metabolized via CYP2C9. An interaction study in healthy volunteers, entacapone increased the AUC of R-warfarin on average by 18%, and the INR values on average by 13%. Cases of increased INR in patients concomitantly using warfarin have been reported during the post-approval use of entacapone. Thus, monitoring of INR is recommended when Stalevo treatment is initiated for patients receiving warfarin.
Read the Stalevo Drug Interactions Center for a complete guide to possible interactions
Last reviewed on RxList: 2/10/2016
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