The most common adverse reactions reported with carbidopa and levodopa therapy have included dyskinesias, such as choreiform, dystonic, and other involuntary movements and nausea.
The following other adverse reactions have been reported with carbidopa and 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 and 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 carbidopa and levodopa tablets 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, falling, 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 crises, 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.