If you have Parkinson’s disease (PD) or parkinsonism, your doctor may prescribe Sinemet for you.

It’s a prescription drug used to treat PD and certain forms of parkinsonism in adults. Specifically, Sinemet is used to treat parkinsonism that happens after:

To learn more about Sinemet’s uses, see the “What is Sinemet used for?” section below.

Sinemet basics

Sinemet comes as a tablet you take by mouth.

Sinemet contains the active drugs carbidopa and levodopa. Carbidopa’s classification is a decarboxylase inhibitor, and levodopa’s classification is a dopamine precursor. To learn how each of these drugs work, see the “What are some frequently asked questions about Sinemet?” section below.

Sinemet is available as a generic drug that contains both carbidopa and levodopa.

Read on to learn about Sinemet’s side effects, dosage, and more.

Like most drugs, Sinemet may cause mild or serious side effects. The lists below describe some of the more common side effects that Sinemet may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Sinemet. They can also suggest ways to help reduce side effects.

To learn about possible side effects of Sinemet in older adults, see the “Side effect focus” section below.

Mild side effects

Here’s a short list of some of the mild side effects that Sinemet can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Sinemet’s prescribing information.

Mild side effects of Sinemet that have been reported include:

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Sinemet can occur. If you have serious side effects, call your doctor right away. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Serious side effects of Sinemet that have been reported include:

* For more information about this side effect, see the “Side effect focus” section below.

SUICIDE PREVENTION

If you think someone is at immediate risk of self-harm or hurting another person:

  • Call 911 or your local emergency number.
  • Stay with the person until help arrives.
  • Remove any guns, knives, medications, or other things that may cause harm.
  • Listen, but don’t judge, argue, threaten, or yell.

If you or someone you know is considering suicide, get help from a crisis or suicide prevention hotline. Try the National Suicide Prevention Lifeline at 800-273-8255.

Side effect focus

Learn more about some of the side effects Sinemet may cause.

Side effects in older people

The side effects of Sinemet in older adults are typically the same as those in younger adults. But those age 65 years and older are more likely to have certain health conditions, such as liver and kidney problems. These conditions can increase the level of Sinemet in your body. And this increases the risk of some side effects, such as hallucinations.*

* For details about hallucinations with Sinemet, see “Hallucinations” just below.

What might help

If you’re age 65 years or above, talk with your doctor before starting Sinemet treatment. They’ll describe the risks and benefits of taking Sinemet and help you determine if the drug is right for you.

Hallucinations / psychotic-like behavior

You may have hallucinations and psychotic-like behavior with Sinemet.

Hallucinations happen when you see or hear things that aren’t really there. In some cases, you may also taste, smell, or feel things that aren’t there.

If you have hallucinations with Sinemet, you may also have:

You may have a higher risk of hallucinations with Sinemet:

  • right after you start taking the drug
  • if you have a history of certain mental health conditions, such as psychosis
  • if you’re age 65 years or older*

Sinemet may also cause abnormal thinking and behavior, including aggressive behavior, agitation, delusions, paranoia and psychotic-like behavior.

* Older adults may have certain health conditions that increase the level of Sinemet in their blood. Or they may have greater sensitivity to some side effects. And this could increase their risk of side effects, such as hallucinations.

What might help

Before taking Sinemet, tell your doctor if you have a history of mental health conditions. They can advise if Sinemet is right for you.

If you have hallucinations while taking Sinemet, talk with your doctor. If you’ve recently started taking the drug, the side effect should go away within a few days to weeks. But your doctor may decide to decrease your dose or switch you to a different medication.

Dyskinesia

You may have dyskinesia with Sinemet. This was one of the most common side effects in studies of the drug.

Dyskinesias are uncontrollable movements that may affect your whole body. Examples include:

  • twitching
  • fidgeting
  • restlessness
  • swaying
  • head bobbing

You may have a higher risk of dyskinesia with Sinemet if you’re also taking tricyclic antidepressants (TCAs), such as amitriptyline.

What might help

Before taking Sinemet, tell your doctor about all other medications you take. They can advise if any of them might increase your risk of dyskinesia with Sinemet.

If you have dyskinesia symptoms while taking Sinemet, talk with your doctor. They may decrease your dose or recommend ways to manage this side effect.

Allergic reaction

Some people may have an allergic reaction to Sinemet. It’s unclear whether allergic reaction was reported in clinical studies of Sinemet, but it can still happen.

Symptoms of a mild allergic reaction can include:

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Sinemet. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Your doctor will recommend the dosage of Sinemet that’s right for you. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Form

Sinemet comes as a tablet you take by mouth.

Recommended dosage

Your Sinemet dosage will be based on:

  • how well your condition is improving with the drug
  • other medical conditions you have
  • other medications you’re taking now or have taken in the past
  • if you’re experiencing certain side effects during therapy

Your doctor will usually start you on a low dosage of Sinemet. Then they’ll adjust your dosage over time to reach the dose that’s right for you.

Sinemet is usually taken three or four times per day at regular dosing intervals. (A dosing interval is the amount of time between each dose.) For example, with Sinemet:

  • If taken three times daily, your dosing interval is every 8 hours.
  • If taken four times daily, your dosing interval is every 6 hours.

Talk with your doctor about the daily recommended maximum dosage of Sinemet.

Questions about Sinemet’s dosage

Below is a list of common questions related to Sinemet’s dosage.

  • What if I miss a dose of Sinemet? If you miss a dose of Sinemet, talk with your doctor or pharmacist. They’ll recommend whether you should take the missed dose or skip it.
  • Will I need to use Sinemet long term? Yes. If Sinemet is working well for you without causing bothersome side effects, you’ll likely take it long term.
  • How long does Sinemet take to work? You should notice your symptoms beginning to ease within 30 minutes of taking Sinemet.

Find answers to some common questions about Sinemet.

How does Sinemet work? What’s its half-life?

Sinemet’s mechanism of action (how it works) is by increasing the level of dopamine in your brain. Dopamine is a chemical that helps your brain control your muscle movements.

Sinemet is used to treat Parkinson’s disease (PD) and certain forms of parkinsonism. With PD and parkinsonism, your brain cells produce less dopamine. This reduced level of dopamine in your brain causes the symptoms of these conditions. (For details, see “What is Sinemet used for?” below.)

Sinemet contains two active drugs: carbidopa and levodopa. These drugs work together to increase the level of dopamine in your brain. Carbidopa keeps your body from breaking down levodopa before it reaches your brain. And once it reaches your brain, levodopa is converted into dopamine.

The half-life of Sinemet is about 1.5 hours. This means it takes about 1.5 hours for your body to get rid of a half of a dose of Sinemet.

Does stopping Sinemet cause withdrawal symptoms? Can you stop taking it ‘cold turkey’?

Yes, stopping Sinemet can lead to withdrawal symptoms. These are side effects that can happen when you stop taking a drug your body has become dependent on.

Stopping Sinemet suddenly or reducing your dosage can cause a life threatening condition similar to neuroleptic malignant syndrome (NMS).

Stopping Sinemet “cold turkey” can cause life threatening symptoms, such as:

Because of this, you should not stop taking Sinemet without talking with your doctor. If they say it’s safe to stop taking the drug, they’ll decrease your dosage slowly over time. This will help reduce your risk of withdrawal symptoms.

What should I do if Sinemet doesn’t seem to be working?

If it seems Sinemet isn’t working for you, talk with your doctor.

Keep in mind that Sinemet’s effects can wear off between doses. This means your symptoms of Parkinson’s disease (PD) or parkinsonism may come back before it’s time for your next dose. Your doctor may adjust your Sinemet dosage to help keep this from happening.

For example, your doctor may suggest you take a higher dose of Sinemet. Or they may have you take the drug more often throughout the day. But don’t adjust your own Sinemet dosage unless your doctor tells you it’s safe to do so.

Is Sinemet similar to alternative drugs such as Stalevo and Parcopa?

Yes, Sinemet is similar to Stalevo and Parcopa.

Sinemet, Stalevo, and Parcopa are used to treat Parkinson’s disease (PD). All three medications contain the active drugs carbidopa and levodopa. Stalevo also contains a third drug called entacapone.

Parcopa was the brand-name form of carbidopa and levodopa tablets that dissolve when placed in the mouth. While brand-name Parcopa is no longer availablein the US, a generic form is.

To learn more about how Sinemet, Stalevo, and Parcopa are alike and different, talk with your doctor or pharmacist.

Does Sinemet cause body odor?

No, Sinemet isn’t known to cause body odor. This side effect wasn’t reported in studies of the drug.

But in some cases, Sinemet may cause you to sweat more than usual. And sweating more than usual could lead to body odor.

If you’re concerned about body odor with Sinemet, talk with your doctor.

Is Sinemet used to treat RLS?

Sinemet isn’t approved to treat restless leg syndrome (RLS). This is a condition that causes an intense urge to move your legs while you’re trying to sleep or rest.

But Sinemet may be used off-label for this purpose. “Off-label” means using a drug for a condition other than those it’s approved to treat.

If you’re interested in using Sinemet to treat RLS, talk with your doctor. They can recommend the best treatment option for you.

If you have Parkinson’s disease (PD) or parkinsonism, your doctor may prescribe Sinemet for you. It’s used to treat PD and certain forms of parkinsonism in adults.

Keep reading to learn more about these conditions and how Sinemet is used to treat them.

Parkinson’s disease (PD)

PD is a condition that leads to loss of coordination and trouble controlling muscle movements. It’s typically caused by damage to the cells in your brain that make dopamine. (Dopamine is a chemical that helps your brain control your muscle movements.)

Symptoms of PD include:

PD usually affects one side of your body more than the other.

Sinemet works by increasing the level of dopamine in your brain. To learn more, see “How does Sinemet work?” in the “What are some frequently asked questions about Sinemet?” section above.

Parkinsonism

Parkinsonism is similar to PD. It’s typically caused by a low level of dopamine in the brain. But with parkinsonism, factors other than damaged brain cells lead to this low dopamine level.

Sinemet is used to treat parkinsonism that happens after:

Like PD, Parkinsonism can cause symptoms such as tremor and loss of coordination. But Parkinsonism typically affects both sides of the body.

Sinemet works by increasing the level of dopamine in your brain. To learn more, see “How does Sinemet work?” in the “What are some frequently asked questions about Sinemet?” section above.

Sinemet and Rytary both contain the same active drugs: carbidopa and levodopa. To learn how Sinemet and Rytary are alike and different, check out this detailed comparison. Also, talk with your doctor to find out which drug is right for you.

Your doctor will explain how you should take Sinemet. They’ll also explain how much to take and how often. Be sure to follow your doctor’s instructions.

Taking Sinemet

Sinemet comes as a tablet you take by mouth.

Accessible medication containers and labels

If it’s hard for you to read the label on your prescription, tell your doctor or pharmacist. Certain pharmacies may provide medication labels that:

  • have large print
  • use braille
  • contain a code you can scan with a smartphone to change the text into audio

Your doctor or pharmacist may be able to recommend a pharmacy that offers these options if your current pharmacy doesn’t.

Also, if you’re having trouble opening your medication bottles, let your pharmacist know. They may be able to put Sinemet in an easy-open container. Your pharmacist may also recommend tools to help make it simpler to open the drug’s container.

Questions about taking Sinemet

Here are answers to important questions about taking Sinemet.

  • Am I supposed to take Sinemet at night? Yes, you can take Sinemet at night. You’ll typically take Sinemet three to four times each day, so you’ll likely take at least one dose in the evening. If you have questions about the best time to take Sinemet, talk with your doctor or pharmacist.
  • Can Sinemet be chewed, crushed, or split? Sinemet’s manufacturer has not indicated whether the tablets can be chewed, crushed, or split. Because of this, you should always swallow the tablets whole. If you have trouble swallowing tablets, check out this article or talk with your doctor or pharmacist.
  • Should I take Sinemet with food? You can take Sinemet with or without food. But note that taking Sinemet along with high-protein foods can affect how well the drug works to treat your condition. For details, see “Other interactions” in the “What should be considered before taking Sinemet?” section below.
Questions for your doctor

You may have questions about Sinemet and your treatment plan. It’s important to discuss all your concerns with your doctor.

Here are a few tips that might help guide your discussion:

  • Before your appointment, write down questions such as:
    • How will Sinemet affect my body, mood, or lifestyle?
  • Bring someone with you to your appointment if doing so will help you feel more comfortable.
  • If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.

Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So don’t be afraid to ask questions or offer feedback on your treatment.

Before taking Sinemet, it’s important to talk with your doctor about the following:

  • other medical conditions you have
  • other medications you take
  • your overall health

These and other considerations are discussed in more detail below.

Interactions

Taking a medication with certain vaccines, foods, and other things can affect how the medication works. These effects are called interactions.

Before taking Sinemet, be sure to tell your doctor about all medications you take, including prescription and over-the-counter types. Also describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with Sinemet.

Interactions with drugs or supplements

Sinemet can interact with several types of drugs. These drugs include:

This list does not contain all types of drugs that may interact with Sinemet. Your doctor or pharmacist can tell you more about these interactions and any others that may occur during Sinemet treatment.

Other interactions

Taking Sinemet along with high-protein foods can affect how well the drug works to treat your condition. Examples of high-protein foods include:

  • eggs
  • Greek yogurt
  • chicken

Foods that are high in protein can:

  • cause your body to take longer to absorb Sinemet
  • reduce the amount of Sinemet your body absorbs

These factors may cause Sinemet to be less effective for managing your condition.

Talk with your doctor about how to manage your protein intake while taking Sinemet.

Warnings

Sinemet may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before starting Sinemet. Factors to consider include those in the list below.

  • Glaucoma. Doctors typically will not prescribe Sinemet if you have a certain type of glaucoma. Sinemet can increase the level of pressure inside your eye, which can be dangerous if you have glaucoma. If you do, talk with your doctor about whether Sinemet is safe for you to take.
  • Mental health conditions. Sinemet can cause hallucinations as a side effect. Hallucinations happen when you see or hear things that aren’t really there. You may have a higher risk of hallucinations if you have history of certain mental health conditions, such as psychosis. Tell your doctor about any mental health conditions you have before starting treatment with Sinemet. They can tell you if this medication is right for you.
  • Peptic ulcers. Before taking Sinemet, tell your doctor if you have a history of peptic ulcers. These are sores in the lining of your esophagus, stomach, or small intestine. If you have or have had this condition, you may be at higher risk of stomach bleeding with Sinemet. Your doctor can tell you if this drug is a safe treatment option for you.
  • Heart or lung conditions. Before taking Sinemet, tell your doctor if you have a history of heart attack, asthma, lung disease, or certain types of arrhythmias. Your doctor can tell you if Sinemet is a safe treatment option for you.
  • Allergic reaction. If you’ve had an allergic reaction to Sinemet or any of its ingredients, your doctor will likely not prescribe Sinemet. Ask your doctor what other medications are better options for you.

Sinemet and alcohol

It may be best to avoid drinking alcohol while you’re taking Sinemet. This is because alcohol can worsen certain side effects of the drug. Examples include:

  • extreme tiredness, which can cause you to fall asleep during regular activities, such as driving
  • digestive problems, such as nausea and vomiting

If you drink alcohol, talk with your doctor before starting Sinemet. They can recommend the amount of alcohol (if any) that’s safe for you to drink while taking this drug

Pregnancy and breastfeeding

It isn’t known if Sinemet is safe to take while pregnant. If you’re pregnant or planning a pregnancy, talk with your doctor before starting Sinemet treatment.

It may not be safe to breastfeed while taking Sinemet either. The drug can pass into breast milk during breastfeeding, which could cause side effects in a breastfed child.

If you’re breastfeeding or planning to breastfeed while taking Sinemet, talk with your doctor. They can discuss any nursing considerations with you.

Costs of prescription drugs can vary depending on many factors. These include what your insurance plan covers and which pharmacy you use. To find current prices for Sinemet tablets in your area, visit GoodRx.com.

Sinemet is available as a generic drug that contains both carbidopa and levodopa. Generics usually cost less than brand-name drugs. Talk with your doctor if you’d like to know more about taking generic carbidopa and levodopa.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. You can also visit the Medicine Assistance Tool’s website to see if they have support options.

You can also check out this article to learn more about saving money on prescriptions.

Don’t take more Sinemet than your doctor prescribes. Taking more than this can lead to serious side effects.

Symptoms of overdose

Symptoms caused by an overdose can include arrhythmia (irregular heart rate or rhythm).

What to do in case you take too much Sinemet

Call your doctor if you think you’ve taken too much Sinemet. You can also call 800-222-1222 to reach the American Association of Poison Control Centers, or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

If you have questions about using Sinemet to treat Parkinson’s disease (PD) or parkinsonism, talk with your doctor. Here are a few examples of questions you may want to ask:

  • Should I use other PD or parkinsonism treatments while taking Sinemet?
  • Will Sinemet interact with any medications I’m taking?
  • What are some alternatives to Sinemet treatment?

If you’re interested in other treatment options, you may find the articles below helpful:

Q:

Can Sinemet cause anxiety?

Anonymous

A:

Yes, Sinemet can cause anxiety. But it isn’t known for sure how common or rare this side effect was in studies of the drug. Anxiety can also be a symptom of Parkinson’s disease. If you’re concerned about anxiety with Sinemet, talk with your doctor. They can recommend ways to help manage this side effect.

Tanya Kertsman, PharmDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.