Sinemet CR Side Effects Center

Last updated on RxList: 6/3/2021
Sinemet CR Side Effects Center

What Is Sinemet CR?

Sinemet CR (carbidopa-levodopa) Sustained-Release Tablets is a dopamine and antiparkinsonism drug used to treat Parkinson's disease. Sinemet CR is available in generic form.

What Are Side Effects of Sinemet CR?

Common side effects of Sinemet CR include:

  • dizziness,
  • nausea,
  • vomiting,
  • sleep problems (insomnia),
  • strange dreams,
  • headache,
  • dry mouth,
  • loss of appetite,
  • heartburn,
  • diarrhea,
  • constipation,
  • drowsiness,
  • blurred vision,
  • sneezing,
  • stuffy nose,
  • cough,
  • other cold symptoms,
  • muscle pain,
  • numbness or tingly feeling, or
  • skin rash or itching.

Sinemet CR may cause your urine, sweat or saliva to turn red, brown, or black. This is harmless, but your clothes may become discolored. Tell your doctor if you have unlikely but serious side effects of Sinemet CR including:

  • greatly increased eye blinking or twitching,
  • fainting,
  • mental/mood changes (e.g., confusion, depression, hallucinations, thoughts of suicide),
  • unusual strong urges (such as increased gambling, increased sexual urges), or
  • worsening of involuntary movements or spasms.

Dosage for Sinemet CR

Talk to your doctor about your individualized dosage recommendation of Sinemet CR.

What Drugs, Substances, or Supplements Interact with Sinemet CR?

Tetrabenazine, isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, and tranylcypromine may interact with Sinemet CR. Tell your doctor all medications you take. Do not drive, use machinery, or do other activity requiring full alertness after using Sinemet CR. Avoid alcohol consumption while taking Sinemet CR.

Sinemet CR During Pregnancy and Breastfeeding

If you are pregnant only use Sinemet CR if clearly needed. Talk to your doctor before taking Sinemet CR if you are breastfeeding.

Additional Information

Our Sinemet CR (carbidopa-levodopa) Sustained-Release Tablets Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Sinemet CR Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);
  • worsening of tremors (uncontrolled shaking);
  • severe or ongoing vomiting or diarrhea;
  • confusion, hallucinations, unusual changes in mood or behavior;
  • depression or suicidal thoughts; or
  • severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Some people taking carbidopa and levodopa have fallen asleep during normal daytime activities such as working, talking, eating, or driving. Tell your doctor if you have any problems with daytime sleepiness or drowsiness.

You may have increased sexual urges, unusual urges to gamble, or other intense urges while taking this medicine. Talk with your doctor if this occurs.

You may notice that your sweat, urine, or saliva appears dark in color, such as red, brown, or black. This is not a harmful side effect, but it may cause staining of your clothes or bed sheets.

Common side effects may include:

  • jerky or twisting muscle movements;
  • headache, dizziness;
  • low blood pressure (feeling light-headed);
  • sleep problems, strange dreams;
  • dry mouth;
  • muscle contractions; or
  • nausea, vomiting, constipation.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Sinemet CR Professional Information


In controlled clinical trials, patients predominantly with moderate to severe motor fluctuations while on SINEMET were randomized to therapy with either SINEMET or SINEMET CR. The adverse experience frequency profile of SINEMET CR did not differ substantially from that of SINEMET, as shown in Table 1.

Table 1: Clinical Adverse Experiences Occurring in 1% or Greater of Patients

Adverse Experience SINEMET CR
n=491 %
n=524 %
Dyskinesia 16.5 12.2
Nausea 5.5 5.7
Hallucinations 3.9 3.2
Confusion 3.7 2.3
Dizziness 2.9 2.3
Depression 2.2 1.3
Urinary tract infection 2.2 2.3
Headache 2.0 1.9
Dream abnormalities 1.8 0.8
Dystonia 1.8 0.8
Vomiting 1.8 1.9
Upper respiratory infection 1.8 1.0
Dyspnea 1.6 0.4
'On-Off' phenomena 1.6 1.1
Back pain 1.6 0.6
Dry mouth 1.4 1.1
Anorexia 1.2 1.1
Diarrhea 1.2 0.6
Insomnia 1.2 1.0
Orthostatic hypotension 1.0 1.1
Shoulder pain 1.0 0.6
Chest pain 1.0 0.8
Muscle cramps 0.8 1.0
Paresthesia 0.8 1.1
Urinary frequency 0.8 1.1
Dyspepsia 0.6 1.1
Constipation 0.2 1.5

Abnormal laboratory findings occurring at a frequency of 1% or greater in approximately 443 patients who received SINEMET CR and 475 who received SINEMET during controlled clinical trials included: decreased hemoglobin and hematocrit; elevated serum glucose; white blood cells, bacteria and blood in the urine.

The adverse experiences observed in patients in uncontrolled studies were similar to those seen in controlled clinical studies.

Other adverse experiences reported overall in clinical trials in 748 patients treated with SINEMET CR, listed by body system in order of decreasing frequency, include:

Body as a Whole

Asthenia, fatigue, abdominal pain, orthostatic effects.


Palpitation, hypertension, hypotension, myocardial infarction.


Gastrointestinal pain, dysphagia, heartburn.


Weight loss.


Leg pain.

Nervous System/Psychiatric

Chorea, somnolence, falling, anxiety, disorientation, decreased mental acuity, gait abnormalities, extrapyramidal disorder, agitation, nervousness, sleep disorders, memory impairment.


Cough, pharyngeal pain, common cold.



Special Senses

Blurred vision.


Urinary incontinence.

Laboratory Tests

Decreased white blood cell count and serum potassium; increased BUN, serum creatinine and serum LDH; protein and glucose in the urine.

The following adverse experiences have been reported in postmarketing experience with SINEMET CR:


Cardiac irregularities, syncope.


Taste alterations, dark saliva.


Angioedema, urticaria, pruritus, bullous lesions (including pemphigus-like reactions).

Nervous System/Psychiatric

Increased tremor, peripheral neuropathy, psychotic episodes including delusions and paranoid ideation, pathological gambling, increased libido including hypersexuality, impulse control symptoms.


Alopecia, flushing, dark sweat.


Dark urine.

Other adverse reactions that have been reported with levodopa alone and with various carbidopa levodopa formulations and may occur with SINEMET CR are:




Gastrointestinal bleeding, development of duodenal ulcer, sialorrhea, bruxism, hiccups, flatulence, burning sensation of tongue.


Hemolytic and non-hemolytic anemia, thrombocytopenia, leukopenia, agranulocytosis.


Henoch-Schönlein purpura.


Weight gain, edema.

Nervous System/Psychiatric

Ataxia, depression with suicidal tendencies, dementia, euphoria, convulsions (however, a causal relationship has not been established); bradykinetic episodes, numbness, muscle twitching, blepharospasm (which may be taken as an early sign of excess dosage; consideration of dosage reduction may be made at this time), trismus, activation of latent Horner's syndrome, nightmares.


Malignant melanoma (see also CONTRAINDICATIONS), increased sweating.

Special Senses

Oculogyric crises, mydriasis, diplopia.


Urinary retention, priapism.


Faintness, hoarseness, malaise, hot flashes, sense of stimulation, bizarre breathing patterns.

Laboratory Tests

Abnormalities in alkaline phosphatase, SGOT (AST), SGPT (ALT), bilirubin, Coombs test, uric acid.

Read the entire FDA prescribing information for Sinemet CR (Carbidopa-Levodopa Sustained Release)

© Sinemet CR Patient Information is supplied by Cerner Multum, Inc. and Sinemet CR Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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