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Sinemet CR Side Effects

Generic name: carbidopa / levodopa

Medically reviewed by Philip Thornton, DipPharm. Last updated on Apr 29, 2022.

Note: This document contains side effect information about carbidopa / levodopa. Some dosage forms listed on this page may not apply to the brand name Sinemet CR.

Applies to carbidopa / levodopa: route not applicable suspension.

Serious side effects of Sinemet CR

Along with its needed effects, carbidopa/levodopa may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking carbidopa / levodopa:

More common

  • Blurred vision
  • chills
  • cold sweats
  • confusion
  • discouragement
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up from lying or sitting position
  • feeling sad or empty
  • full feeling
  • headache
  • irritability
  • lack of appetite
  • loss of interest or pleasure
  • nervousness
  • pounding in the ears
  • pressure in the stomach
  • rapid weight gain
  • slow or fast heartbeat
  • swelling of the abdominal or stomach area
  • tingling of the hands or feet
  • tiredness
  • trouble concentrating
  • trouble sleeping
  • twitching, twisting, or uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
  • unusual weight gain or loss

Less common

  • Burning, numbness, tingling, or painful sensations
  • confusion about identity, place, and time
  • dry mouth
  • false beliefs that cannot be changed by facts
  • feeling that others are watching you or controlling your behavior
  • holding false beliefs that cannot be changed by fact
  • hyperventilation
  • irregular heartbeats
  • restlessness
  • seeing, hearing, or feeling things that are not there
  • severe constipation
  • severe mood or mental changes
  • severe vomiting
  • shaking
  • shortness of breath
  • trouble sleeping
  • unsteadiness or awkwardness
  • unusual behavior
  • unusual excitement, nervousness, or restlessness
  • weakness in the arms, hands, legs, or feet


  • Change in size, shape, or color of existing mole
  • mole that leaks fluid or bleeds
  • new mole

Incidence not known

  • Blindness
  • chest pain or discomfort
  • constipation that does not go away
  • convulsions
  • dark, tarry stools
  • decreased vision
  • difficulty with breathing
  • eye pain
  • high fever
  • increased sweating
  • loss of bladder control
  • nausea or vomiting
  • pain in the shoulders, arms, jaw, or neck
  • severe muscle stiffness
  • tearing
  • unusually pale skin

Other side effects of Sinemet CR

Some side effects of carbidopa / levodopa may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

Incidence not known

  • Sleepiness
  • unusual drowsiness

For Healthcare Professionals

Applies to carbidopa / levodopa: enteral suspension, oral capsule extended release, oral tablet, oral tablet disintegrating, oral tablet extended release.


The most common adverse reactions reported include nausea, dizziness, headache, insomnia, abnormal dreams, dry mouth, dyskinesia, anxiety, constipation, vomiting, and orthostatic hypotension.[Ref]

Nervous system

Very common (10% or more): Headache (up to 17%), dyskinesia (up to 16.5%), dizziness (up to 12%)

Common (1% to 10%): Confusion, dystonia, on-off phenomena, hypoesthesia, polyneuropathy, tremor, dysgeusia, bradykinesia

Uncommon (0.1% to 1%): Paresthesia, ataxia, gait disturbance, convulsion

Rare (less than 0.1%): Malignant, neuroleptic syndrome

Frequency not reported: Chorea, somnolence, memory impairment, sense of stimulation

Postmarketing reports: Polyneuropathy[Ref]


Very common (10% or more): Anxiety, insomnia, depression (up to 11%)

Common (1% to 10%): Hallucinations, psychosis, abnormal dreams, sleep disorder, agitation, impulsive behavior, sleep attacks

Uncommon (0.1% to 1%): Suicide, dementia, disorientation, euphoric mood, fear

Rare (less than 0.1%): Abnormal thinking

Postmarketing: Suicide attempt, suicidal ideation[Ref]


Very common (10% or more): Nausea (up to 30%), constipation (up to 22%)

Common (1% to 10%): Dry mouth, constipation, vomiting, hiatal hernia, postoperative ileus, diarrhea, dyspepsia, abdominal distension, dysphagia, flatulence, bitter taste

Uncommon (0.1% to 1%): Salivary hypersecretion

Rare (less than 0.1%): Bruxism, saliva discoloration, glossodynia, hiccups, trismus, burning tongue sensation

Frequency not reported: Heartburn[Ref]


Common (1% to 10%): Ischemic events, orthostatic hypotension, peripheral edema, hypertension, syncope, irregular heart rate, hypotension

Uncommon (0.1% to 1%): Palpitations, phlebitis

Frequency not reported: Chest pain, myocardial infarction[Ref]

Cardiovascular ischemic events occurred in 2.4% (7 of 289) patients receiving carbidopa-levodopa extended-release capsules compared to 1.1% (1 of 92) of patients receiving placebo in early Parkinson's disease clinical trials. In advanced Parkinson's disease, 0.7 % (3 of 450) patients experienced cardiovascular ischemic events. These patients had a previous history of ischemic heart disease or risk factors for ischemic heart disease.[Ref]


Common (1% to 10%): Excessive granulation tissue, rash, contact dermatitis, hyperhidrosis, pruritus

Uncommon (0.1% to 1%): Alopecia, erythema, urticaria

Rare (less than 0.1%): Sweat discoloration, angioedema

Postmarketing reports: Henoch-Schonlein purpura[Ref]


Very common (10% or more): Insertion site complication, incision site erythema (19%), post-operative wound infection

Common (1% to 10%): Incision site cellulitis, post procedural infection, device dislocation, device occlusion

Uncommon (0.1% to 1%): Postoperative abscess, bezoar, ischemic colitis

Postmarketing reports: Gastric perforation, gastrointestinal perforation, small intestinal ischemia, small intestinal perforation[Ref]

Insertion site complication was reported in 57% of patients who received this drug compared with 44% of patients who received a PEG-J tube without receiving treatment. The most common adverse reactions associated with naso-jejunal (NJ) insertion were oropharyngeal pain, abdominal distention, abdominal pain, abdominal discomfort, pain, throat irritation, gastrointestinal injury, esophageal hemorrhage, anxiety, dysphagia, and vomiting. The most common adverse reactions associated with PEG-J insertion included upper abdominal pain, duodenal ulcer, duodenal ulcer hemorrhage, erosive duodenitis, erosive gastritis, gastrointestinal hemorrhage, intussusception, peritonitis, post-operative abscess, and small intestine ulcer.[Ref]


Postmarketing reports: Anaphylactic reaction, bullous lesions[Ref]


Common (1% to 10%): Upper respiratory tract infection, atelectasis, dyspnea, aspiration pneumonia, oropharyngeal pain

Uncommon (0.1% to 1%): Dysphonia, hoarseness

Rare (less than 0.1%): Abnormal respiration

Frequency not reported: Bizarre breathing pattern[Ref]


Frequency not reported: Elevated alkaline phosphatases, AST, ALT, LDH, and bilirubin[Ref]


Frequency not reported: Elevated serum urea and creatinine[Ref]


Very common (10% or more): Asthenia, fatigue

Common (1% to 10%): Pyrexia, malaise

Frequency not reported: Hot flashes[Ref]


Common (1% to 10%): Urinary tract infection, urinary incontinence, urinary retention

Uncommon (0.1% to 1%): Urinary frequency

Rare (less than 0.1%): Priapism[Ref]


Common (1% to 10%): Anemia

Uncommon (0.1% to 1%): Leukopenia, thrombocytopenia

Rare (less than 0.1%): Hemolytic anemia

Very rare (less than 0.01%): Agranulocytosis

Frequency not reported: Positive Coombs test, reduced hemoglobin and hematocrit[Ref]


Very common (10% or more): Decreased weight

Common (1% to 10%): Anorexia, increased weight, vitamin B6 deficiency, vitamin B12 deficiency

Frequency not reported: Elevated blood sugar

Postmarketing reports: Folic acid deficiency[Ref]


Common (1% to 10%): Back pain, shoulder pain

Uncommon (0.1% to 1%): Muscle cramps, neck pain

Frequency not reported: Muscle twitching, leg pain[Ref]


Uncommon (0.1% to 1%): Blepharospasm, diplopia, optic ischemic neuropathy, blurred vision

Rare (less than 0.1%): Mydriasis, oculogyric crisis, activation of a latent Horner's syndrome[Ref]


Rare (less than 0.1%): Malignant melanoma[Ref]

Frequently asked questions


1. "Product Information. Sinemet (carbidopa-levodopa)." DuPont Pharmaceuticals (2001):

2. "Product Information. Sinemet CR (carbidopa-levodopa)." DuPont Pharmaceuticals (2001):

3. "Product Information. Parcopa (carbidopa-levodopa)." Schwarz Pharma (2004):

4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

5. Cerner Multum, Inc. "Australian Product Information." O 0

6. "Product Information. Rytary (carbidopa-levodopa)." Impax Generics (2015):

7. "Product Information. Duopa (carbidopa-levodopa)." AbbVie US LLC (2015):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.