Sinemet Side Effects

Generic name: carbidopa/levodopa

Please note - some side effects for Sinemet may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Sinemet - for the consumer

Sinemet

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Sinemet:

Confusion; constipation; diarrhea; dizziness; drowsiness; dry mouth; headache; increased sweating; loss of appetite; nausea; taste changes; trouble sleeping; upset stomach; urinary tract infection; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry stools; blood in vomit; chest pain; confusion; depression; fast or irregular heartbeat; fever; hallucinations; mental or mood changes; muscle pain or unusual stiffness; severe abdominal pain; severe lightheadedness or fainting; sore throat; thoughts of suicide; unexplained fever or sweating; unusual bruising or bleeding; unusual or painful movements or spasms of the face, eyelids, mouth, tongue, arms, hands, or legs; vision changes (blurred/double vision); yellowing of the skin or eyes.

Sinemet CR Sustained-Release Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Sinemet CR Sustained-Release Tablets:

Confusion; constipation; diarrhea; dizziness; drowsiness; dry mouth; headache; increased sweating; loss of appetite; nausea; taste changes; trouble sleeping; upset stomach; urinary tract infection; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry stools; blood in vomit; chest pain; confusion; depression; fast or irregular heartbeat; fever; hallucinations; mental or mood changes; muscle pain or unusual stiffness; severe abdominal pain; severe lightheadedness or fainting; sore throat; thoughts of suicide; unexplained fever or sweating; unusual bruising or bleeding; unusual or painful movements or spasms of the face, eyelids, mouth, tongue, arms, hands, or legs; vision changes (blurred/double vision); yellowing of the skin or eyes.

For the professional

Sinemet

The most common adverse reactions reported with Sinemet have included dyskinesias, such as choreiform, dystonic, and other involuntary movements and nausea.

The following other adverse reactions have been reported with Sinemet:

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, 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, pathological gambling, increased libido including hypersexuality, impulse control symptoms. Convulsions also have occurred; however, a causal relationship with Sinemet 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 Sinemet 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, 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.

By body system

General side effects

Although the optimal timing of the initiation of levodopa therapy is controversial, some investigators have suggested that early treatment of parkinsonism with levodopa delays disease progression and decreases mortality.

Adverse effects attributable to levodopa occur frequently regardless of whether carbidopa is taken concomitantly or not. In contrast, carbidopa is fairly well tolerated and is rarely reported to cause adverse effects. Carbidopa may reduce the incidence of vomiting, nausea and anorexia in patients treated with levodopa. Carbidopa, however, does not alter the frequency of central adverse effects.

Nervous system side effects

Nervous system effects occur in as many as 50% of treated patients on long-term therapy and include involuntary movements and mental status changes most frequently. The types of involuntary movements due to levodopa have been characterized as choreiform, dystonic and dyskinetic. Fluctuations in motor function occur frequently and often increase as the duration of therapy increases.

Choreiform movements due to levodopa therapy may occur in as many as 80% of patients treated for one year and frequently involve facial grimacing, exaggerated chewing and twisting and protrusion of the tongue.

Several types of motor fluctuations may occur and result in "bradykinetic episodes". Some motor fluctuations are related to the timing of dosage administration. For example, patients may experience "peak of the dose dyskinesia" and a wearing-off effect called "end of the dose akinesia". The "wearing-off" may result in early morning dystonia. Such motor fluctuations may be managed by increasing the frequency of dose administration and decreasing the dose administered (or possibly by use of extended release formulations) to achieve a smoother therapeutic effect.

Other motor fluctuations are not related to the timing of dose administration. Such fluctuations are characterized by sudden loss of levodopa effect which may last for minutes to hours and result in akinesia followed by a sudden return of levodopa effect. These "on-off" fluctuations may occur many times per day. "On-off" fluctuations may respond to more frequent dose administration.

Finally, akinesia paridoxica is a sudden episode of akinesia which occurs as patients begin to walk. Akinesia paridoxica frequently results in falls and often responds to levodopa dose reductions.

Other adverse nervous system effects due to levodopa include myoclonus, sleep disturbances (including insomnia, daytime somnolence, altered dreams and episodic nocturnal myoclonus), Meige's syndrome (blepharospasm-oromandibular dystonia) and ocular dyskinesia. In addition, the orofacial movements induced by levodopa have occasionally been reported to cause severe dental erosion.

Some investigators have suggested that levodopa may cause brain dysfunction and may have negative effects on cognitive performance.

Levodopa "drug holidays" have been proposed by some investigators as potentially beneficial (perhaps by causing dopamine receptor resensitization). However, the therapeutic value of these drug holidays is controversial.

Gastrointestinal side effects

Gastrointestinal side effects including nausea and vomiting are the most common adverse gastrointestinal effects of levodopa. Anorexia and, rarely, gastrointestinal hemorrhage have been reported.

Exacerbation of preexisting ulcer disease with severe upper gastrointestinal bleeding has been reported.

Psychiatric side effects

Psychiatric effects include hallucinations (particularly visual hallucinations), psychosis, confusion, anxiety, mania, hypomania, depression, rapid mood cycling, nightmares, and hypersexuality.

Some authors have suggested that clozapine may be useful in the management of levodopa-induced psychotic symptoms.

Other investigators have suggested that levodopa may induce alterations in the noradrenergic systems of the CNS which may lead to panic attacks.

Other side effects

Fever, altered consciousness, autonomic dysfunction and muscle rigidity are the hallmarks of the neuroleptic malignant syndrome. The neuroleptic malignant syndrome (NMS) is associated with a case fatality rate of about 20%. If withdrawal of dopaminergic therapy is suspected as the cause of NMS, dopaminergic therapy should be restarted. If a neuroleptic agent is suspected as the cause, the neuroleptic agent should be immediately discontinued. For patients with NMS suspected to be due to neuroleptic therapy, consideration should be given to dantrolene (or bromocriptine) administration. Intensive monitoring and supportive care are indicated for all patients with NMS.

Sudden discontinuation or rapid tapering of levodopa therapy may result in acute worsening of parkinsonism or, less frequently, in a syndrome resembling the neuroleptic malignant syndrome. Cases of psychologic levodopa addiction have also been reported rarely.

Cardiovascular side effects

Some authors have reported marked hemodynamic and clinical improvements in patients with congestive heart failure treated with oral levodopa. However, at least one author has reported marked hemodynamic deterioration following such treatment.

Cardiovascular effects include hypotension and syncope. Arrhythmias have also been reported rarely.

Dermatologic side effects

Dermatologic side effects including a number of cases of malignant melanoma have been reported in patients taking levodopa for Parkinson's Disease. Additionally, several cases of maculopapular skin rashes have been reported in patients taking levodopa-containing drugs.

Despite reports of melanoma occurring in levodopa-treated patients, some authors have suggested that a causal association is tenuous and other authors have suggested that levodopa may have an antitumor effect on melanoma. Nevertheless, the manufacturers of levodopa-containing drugs report that either the history of melanoma or the presence of suspicious skin lesions is a contraindication for the use of levodopa-containing drugs.

One author has suggested that some rashes reported in association with levodopa therapy may be related to the presence of a yellow dye in Sinemet 25/100.

Immunologic side effects

Immunologic side effects including rare lupus-like syndrome have been suggested by some authors.

Hematologic side effects

Hematologic side effects including severe hemolytic and nonhemolytic anemias have been reported rarely.

Respiratory side effects

Respiratory dyskinesias (occasionally of life-threatening severity) have been reported.

Hepatic side effects

Hepatic effects including asterixis (without abnormalities of liver function tests) have been reported rarely. The manufacturer of levodopa-containing products report that abnormal liver function tests may occur.

Endocrine side effects

Endocrine side effects including elevated urinary vanillylmandelic acid levels during levodopa therapy have occasionally let to confusion concerning the diagnosis of pheochromocytoma.

Renal side effects

Renal side effects including Hypokalemia and hyponatremia have been reported. Chronic administration of levodopa may also slightly but significantly increase BUN without changes in the glomerular filtration rate.

Hypersensitivity side effects

Hypersensitivity, type III, adverse effects have been reported in a 68-year-old man with Parkinson's after the use of carbidopa-levodopa, which manifested as purpura of the limbs, vasculitis and glomerulonephritis. The diagnosis of Henoch-Schonlein syndrome was confirmed after drug rechallenge.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date, and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This information does not endorse drugs, diagnose patients, or recommend therapy. This drug information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug of drug combination is safe, effective, or appropriate for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of information provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.