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Uses

What is carbidopa/levodopa used for?

Carbidopa/levodopa is commonly used to treat Parkinson’s disease, a condition that affects the part of your brain that controls your movements. It may also be used to treat conditions with symptoms similar to Parkinson’s disease (called parkinsonism).

Carbidopa/levodopa may also be used for other conditions as determined by your healthcare provider.

How does carbidopa/levodopa work (mechanism of action)?

In people with Parkinson's disease, the brain does not have enough of a chemical called dopamine, which helps control movement. This makes it hard for people to move their bodies the way they want to.

Carbidopa and levodopa are medicines that work together to help people with Parkinson's disease.

Levodopa is a medicine that turns into dopamine in the brain. When levodopa is used by itself, it gets broken down too quickly, before it can reach the brain. Carbidopa works to block the breakdown of levodopa so that more dopamine can get to the brain. This helps people with Parkinson's disease move more easily.

How is carbidopa/levodopa supplied (dosage forms)?

Brands and other names

  • Sinemet
  • Sinemet CR

Dosage forms and strengths

  • 25 mg/100 mg extended-release oral tablets
  • 50 mg/200 mg extended-release oral tablets
  • 10 mg/100 mg oral tablets
  • 25 mg/100 mg oral tablets
  • 25 mg/250 mg oral tablets
  • 10 mg/100 mg orally disintegrating tablets
  • 25 mg/100 mg orally disintegrating tablets
  • 25 mg/250 mg orally disintegrating tablets

How should I store carbidopa/levodopa?

Carbidopa/levodopa should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Keep the container tightly closed. Protect from light and moisture.

Side Effects

What are the most common side effects of carbidopa/levodopa?

The most common side effects of carbidopa/levodopa are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Uncontrollable, involuntary movements (see below)
  • Nausea

There may be other side effects of carbidopa/levodopa that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of carbidopa/levodopa?

While less common, the most serious side effects of carbidopa/levodopa are described below, along with what to do if they happen.

Severe Allergic Reactions. Carbidopa/levodopa may cause allergic reactions, which can be serious. Stop taking carbidopa/levodopa and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Depression and Suicidal Thoughts. Carbidopa/levodopa may cause depression in a small number of people. If you having thoughts of harming yourself, call 911 or call or text 988, the Suicide & Crisis Lifeline. Call your healthcare provider right away if you have any of the following symptoms.

  • New or increased thoughts of suicide or death
  • Suicide attempt
  • New or increased feelings of anxiety, depression, or other unusual changes in mood or behavior

Sleepiness. Carbidopa/levodopa can make you sleepy, sometimes very suddenly and without warning signs (also called a "sleep attack"). Do not drive or do other activities that require alertness or coordination until you know how carbidopa/levodopa affects you. Tell your healthcare provider if you feel sleepy or drowsy while taking carbidopa/levodopa.

Uncontrollable, Involuntary Movements (Dyskinesias). Carbidopa/levodopa may cause involuntary movement problems, including shakiness, stiffness, or jerkiness. Call your healthcare provider right away if you develop any unusual or uncontrolled movements or if they get worse.

Hallucinations or Psychotic-like Behaviors. Carbidopa/levodopa may cause hallucinations or psychotic-like behaviors. Talk to your healthcare provider right away if you or someone you know notices that you have any of the following symptoms.

  • Hearing, seeing, smelling, tasting, or otherwise perceiving things that others do not
  • Delusional thoughts, such as false beliefs that you are being controlled
  • Disorganized thoughts, such as jumping between topics or having a hard time focusing
  • Sudden decline in self-care, such as personal hygiene or academic/work performance
  • Aggressive behavior

Unusual or Compulsive Behaviors. Carbidopa/levodopa can cause some people to have strong unusual and uncontrolled urges (compulsions), including gambling, sex, shopping, or eating. Talk to your healthcare provider right away if you or someone you know notices that you have new or worsening strong urges or behaviors.

Warnings & Precautions

Who should not use carbidopa/levodopa?

Allergies to Ingredients. People who are allergic to any of the following should not take carbidopa/levodopa.

  • Levodopa
  • Carbidopa
  • Sinemet
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific carbidopa/levodopa products they stock.

Drug Interactions. Carbidopa/levodopa should not be taken while you are using or if you have recently used certain other medicines. Before taking carbidopa/levodopa, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Glaucoma. People with certain types of glaucoma should not take carbidopa/levodopa. Tell your healthcare provider if you have glaucoma.

What should I know about carbidopa/levodopa before using it?

Do not take carbidopa/levodopa unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share carbidopa/levodopa with other people, even if they have the same condition as you. It may harm them.

Keep carbidopa/levodopa out of the reach of children.

Do not chew or crush carbidopa/levodopa extended-release capsules or tablets. 

Do not stop taking carbidopa/levodopa without talking to your healthcare provider. Stopping too quickly may cause serious side effects. Call your healthcare provider right away if you have any of the following symptoms.

  • High fever
  • Muscle stiffness or rigidity, where it is hard to move
  • Changes in your breathing or heart rate
  • Increased sweating
  • Confusion

You may notice a dark color in your saliva, sputum, urine, or sweat. This is a common side effect of carbidopa/levodopa and is not believed to be harmful. However, your clothes might get stained.

Carbidopa/levodopa may cause you to feel sleepy, especially if you already have conditions that can make you drowsy. Carbidopa/levodopa may also cause dizziness, especially when you stand up quickly after lying or sitting down. If this occurs, get up slowly after sitting or lying down. Do not drive or do other activities that require alertness or coordination until you know how carbidopa/levodopa affects you.

Monitor your skin for changes while taking carbidopa/levodopa. Keep any appointments to have your skin checked.

What should I tell my healthcare provider before using carbidopa/levodopa?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if carbidopa/levodopa is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Mental health or behavior problems, including depression or any psychotic disorder (such as schizophrenia or delusional disorder)
  • Sleep problems
  • Heart problems, such as a prior heart attack, heart disease, or an abnormal heart rhythm
  • Low blood pressure or feeling faint or dizzy, especially when standing up from a seated or lying position
  • Breathing problems, such as asthma
  • Stomach problems, such as a stomach ulcer
  • Kidney or liver problems
  • Hormone problems (endocrine disorders), such as diabetes or thyroid problems

Pregnancy. It is not known if or how carbidopa/levodopa could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take carbidopa/levodopa while you are pregnant or trying to get pregnant.

Breastfeeding. Levodopa, one of the medicines in carbidopa/levodopa, passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take carbidopa/levodopa while breastfeeding.

Phenylketonuria (PKU). Carbidopa/levodopa orally disintegrating tablets contain phenylalanine, which can be dangerous for people with phenylketonuria (PKU). Tell your healthcare provider and your pharmacist if you have PKU and are prescribed carbidopa/levodopa orally disintegrating tablets.

Interactions

Does carbidopa/levodopa interact with foods or drinks?

High-protein foods may affect how well your body absorbs levodopa (one of the two medicines in carbidopa/levodopa) and decrease how well carbidopa/levodopa works. If you change the amount of protein in your diet, tell your healthcare provider.

It is unknown if drinking alcohol will affect carbidopa/levodopa. However, the risk of drowsiness, sleepiness, and/or dizziness may be increased if you drink alcohol while taking carbidopa/levodopa. 

Does carbidopa/levodopa interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking carbidopa/levodopa.

  • A nonselective monoamine oxidase inhibitor (MAOI) within the past 2 weeks, such as phenelzine (Nardil), tranylcypromine (Parnate), or isocarboxazid (Marplan), which is a medicine usually used for depression
  • A selective monoamine oxidase B (MAO-B) inhibitor, such as rasagiline or selegiline, which is a medicine usually used for depression or Parkinson’s disease
  • A medicine for high blood pressure
  • A tricyclic antidepressant, such as amitriptyline, nortriptyline, or protriptyline, even if it is not used for depression
  • An antipsychotic, such as haloperidol, chlorpromazine, thioridazine, fluphenazine, or risperidone, which is a medicine for certain mental health conditions
  • Isoniazid, which is a medicine used to treat an infection called tuberculosis
  • Phenytoin (Dilantin, Phenytek, and others), which is a medicine to control seizures
  • Papaverine, which is a medicine used for various blood flow problems, including chest pain
  • Tetrabenazine, which is a medicine used to treat symptoms of Huntington’s disease
  • Iron supplements or other products (such as multivitamins) containing iron
  • Metoclopramide (Reglan and others), which is a medicine for certain stomach problems
  • Any other medicine that causes dizziness and sleepiness, such as prescription pain medicines, sleep medicines, and medicines for anxiety
  • Any other medicine that contains carbidopa or levodopa

This may not be a complete list of medicines that can interact with carbidopa/levodopa. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much carbidopa/levodopa?

If you or someone else has used too much carbidopa/levodopa, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of carbidopa/levodopa?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.