Carbidopa / Levodopa Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on Mar 17, 2024.

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

Precautions

It is very important that your doctor check your progress at regular visits to allow changes in your dose. Blood and urine tests may be needed to check for any unwanted effects.

Do not take this medicine together with non-selective MAO inhibitor (eg, phenelzine, linezolid, tranylcypromine, Nardil®, Parnate®, Zyvox®) in the past 2 weeks.

Do not Stop taking carbidopa / levodopa without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping completely.

Check with your doctor right away if you are having convulsions (seizures), difficulty with breathing, a fast heartbeat, a high fever, high or low blood pressure, increased sweating, loss of bladder control, severe muscle stiffness, unusually pale skin, or tiredness. These could be symptoms of a serious condition called neuroleptic malignant syndrome (NMS).

This medicine may cause dizziness, drowsiness, trouble in controlling movements, or trouble concentrating, or seeing clearly. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

It is important that your doctor check your skin regularly for signs of a skin cancer called melanoma. If you notice any unusual red, brown, or black spots on your skin, talk to your doctor right away.

If you develop any unusual or strange thoughts and behavior while receiving this medicine, be sure to discuss it with your doctor. Other changes might be confusion, worsening of depression, visual hallucinations (seeing things that are not there), suicidal thoughts, and unusual excitement, nervousness, or irritability.

It is possible that a dark color (red, brown, or black) may appear in saliva, urine, or sweat after taking this medicine. The color may cause some of your garments to become discolored. This is normal and nothing to worry about.

It is possible that you may become nauseous, especially when you are first starting your medicine.

This medicine may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. Also tell your doctor if you have sudden or strong feelings, such as feeling nervous, angry, restless, violent, or scared. If you, your child, or your caregiver notice any of these adverse effects, tell your doctor or your child's doctor right away.

Some people who have used this medicine had unusual changes in their behavior. Talk with your doctor right away if you start having problems with gambling or an increased interest in sex while using this medicine.

This medicine may cause uncontrolled sudden movements (dyskinesia) or make such movements you already have worse or more frequent. Tell your doctor if this happens.

Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects

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:

Other side effects

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:

For healthcare professionals

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

General adverse events

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]

Psychiatric

• 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]

Gastrointestinal

• 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]

Cardiovascular

• 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]

Dermatologic

• 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]

Local

• 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]

Hypersensitivity

• Postmarketing reports: Anaphylactic reaction, bullous lesions^[Ref]

Respiratory

• 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]

Hepatic

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

Renal

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

Other

• Very common (10% or more): Asthenia, fatigue
• Common (1% to 10%): Pyrexia, malaise
• Frequency not reported: Hot flashes^[Ref]

Genitourinary

• 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]

Hematologic

• 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]

Metabolic

• 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]

Musculoskeletal

• 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]

Ocular

• 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]

Oncologic

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

See also:

Frequently asked questions

• How long does it take carbidopa levodopa to work?
• How often should carbidopa/levodopa be taken?
• Can carbidopa/levodopa cause high blood pressure?
• What foods should be avoided when taking levodopa?
• Is Rytary better than Sinemet?
• What is the difference between carbidopa, levodopa, and Rytary?
• How long does it take for Rytary to start working?
• How long does Rytary stay in your system?

Further information

Carbidopa/levodopa side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer