The most common adverse reactions reported with carbidopa-levodopa have included dyskinesias, such as choreiform, dystonic, and other involuntary movements and nausea.
The following other adverse reactions have been reported with carbidopa-levodopa:
Body as a Whole: Chest pain, asthenia.
Cardiovascular: Cardiac irregularities, hypotension, orthostatic effects including orthostatic hypotension, hypertension, syncope, phlebitis, palpitation.
Gastrointestinal: Dark saliva, gastrointestinal bleeding, development of duodenal ulcer, anorexia, vomiting, diarrhea, constipation, dyspepsia, dry mouth, taste alterations.
Hematologic: Agranulocytosis, hemolytic and non-hemolytic anemia, thrombocytopenia, leukopenia.
Hypersensitivity: Angioedema, urticaria, pruritus, Henoch-Schonlein purpura, bullous lesions (including pemphigus-like reactions).
Musculoskeletal: Back pain, shoulder pain, muscle cramps.
Nervous System/Psychiatric: Psychotic episodes including delusions, hallucinations, and paranoid ideation, neuroleptic malignant syndrome (see WARNINGS), bradykinetic episodes ("on-off' phenomenon), confusion, agitation, dizziness, somnolence, dream abnormalities including nightmares, insomnia, paresthesia, headache, depression with or without development of suicidal tendencies, dementia, increased libido. Convulsions also have occurred; however, a causal relationship with carbidopa-levodopa has not been established.
Respiratory: Dyspnea, upper respiratory infection.
Skin: Rash, increased sweating, alopecia, dark sweat.
Urogenital: Urinary tract infection, urinary frequency, dark urine.
Laboratory Tests: Decreased hemoglobin and hematocrit; abnormalities in alkaline phosphatase, SGOT (AST), SGPT (ALT), lactic dehydrogenase, bilirubin, blood urea nitrogen (BUN), Coombs' test; elevated serum glucose; white blood cells, bacteria, and blood in the urine.
Other adverse reactions that have been reported with levodopa alone and with various carbidopa-levodopa formulations, and may occur with Stalevo® (carbidopa, levodopa and entacapone) are:
Body as a Whole: Abdominal pain and distress, fatigue. Cardiovascular: Myocardial infarction.
Gastrointestinal: Gastrointestinal pain, dysphagia, sialorrhea, flatulence, bruxism, burning sensation of the tongue, heartburn, hiccups.
Metabolic: Edema, weight gain, weight loss.
Musculoskeletal: Leg pain.
Nervous System/Psychiatric: Ataxia, extrapyramidal disorder, failing, anxiety, gait abnormalities, nervousness, decreased mental acuity, memory impairment, disorientation, euphoria, blepharospasm (which may be taken as an early sign of excess dosage; consideration of dosage reduction may be made at this time), trismus, increased tremor, numbness, muscle twitching, activation of latent Horner's syndrome, peripheral neuropathy.
Respiratory: Pharyngeal pain, cough.
Skin: Malignant melanoma (see also CONTRAINDICATIONS), flushing.
Special Senses: Oculogyric crisis, diplopia, blurred vision, dilated pupils.
Urogenital: Urinary retention, urinary incontinence, priapism.
Miscellaneous: Bizarre breathing patterns, faintness, hoarseness, malaise, hot flashes, sense of stimulation.
Laboratory Tests: Decreased white blood cell count and serum potassium; increased serum creatinine and uric acid; protein and glucose in urine.
The most commonly observed adverse events ( > 5%) in the double-blind, placebo-controlled trials of entacapone (N=1003) associated with the use of entacapone alone and not seen at an equivalent frequency among the placebo-treated patients were: dyskinesia/hyperkinesia, nausea, urine discoloration, diarrhea, and abdominal pain.
Approximately 14% of the 603 patients given entacapone in the double-blind, placebo-controlled trials discontinued treatment due to adverse events compared to 9% of the 400 patients who received placebo. The most frequent causes of discontinuation in decreasing order are: psychiatric reasons (2% vs. 1%), diarrhea (2% vs. 0%), dyskinesia/hyperkinesia (2% vs. 1%), nausea (2% vs. 1%), abdominal pain (1% vs. 0%), and aggravation of Parkinson's disease symptoms (1% vs. 1%).
Adverse Event Incidence in Controlled Clinical Studies of Entacapone
Table 5 lists treatment emergent adverse events that occurred in at least 1% of patients treated with entacapone participating in the double-blind, placebo-controlled studies and that were numerically more common in the entacapone group, compared to placebo. In these studies, either entacapone or placebo was added to carbidopa-levodopa (or benserazide-levodopa).
Table 5: Summary of Patients With Adverse Events After Start of Trial Drug Administration At Least 1% in Entacapone Group and > Placebo
| SYSTEM ORGAN CLASS
(n = 603)
% of patients
(n = 400)
% of patients
|SKIN AND APPENDAGES DISORDERS|
|MUSCULOSKELETAL SYSTEM DISORDERS|
|CENTRAL & PERIPHERAL NERVOUS SYSTEM DISORDERS|
|SPECIAL SENSES, OTHER DISORDERS|
|GASTROINTESTINAL SYSTEM DISORDERS|
|Gastrointestinal Disorders NOS||1||0|
|RESPIRATORY SYSTEM DISORDERS|
|PLATELET, BLEEDING & CLOTTING DISORDERS|
|URINARY SYSTEM DISORDERS|
|BODY AS A WHOLE - GENERAL DISORDERS|
|RESISTANCE MECHANISM DISORDERS|
The prescriber should be aware that these figures cannot be used to predict the incidence of adverse events in the course of usual medical practice where patient characteristics and other factors differ from those that prevailed in the clinical studies. Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigations involving different treatments, uses, and investigators. The cited figures do, however, provide the prescriber with some basis for estimating the relative contribution of drug and nondrug factors to the adverse events observed in the population studied.
Effects of Gender and Age on Adverse Reactions
No differences were noted in the rate of adverse events attributable to entacapone alone by age or gender.
Drug Abuse And Dependence
Controlled substance class: Stalevo (carbidopa, levodopa and entacapone) ® (carbidopa, levodopa and entacapone) is not a controlled substance.
Physical and psychological dependence: Stalevo (carbidopa, levodopa and entacapone) ® has not been systematically studied, in animal or humans, for its potential for abuse, tolerance or physical dependence. In premarketing clinical experience, carbidopa-levodopa did not reveal any tendency for a withdrawal syndrome or any drug-seeking behavior. However, there are rare postmarketing reports of abuse and dependence of medications containing levodopa. In general, these reports consist of patients taking increasing doses of medication in order to achieve a euphoric state.