Sinemet Interactions: Alcohol, Medications, and Others

Does Sinemet interact with other drugs?

Before you start taking Sinemet, tell your doctor and pharmacist about any prescription, over-the-counter, or other drugs you take. Sharing this information with them may help prevent possible interactions. (To learn whether Sinemet interacts with supplements, herbs, and vitamins, see the “Are there other interactions with Sinemet?” section below.)

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

The table below lists drugs that may interact with Sinemet. Keep in mind that this table does not include all drugs that may interact with Sinemet. For more information about some of these interactions, see the “Drug interactions explained” section below.

* To learn more, see the “When should I avoid Sinemet?” section below.

When should I avoid Sinemet?

Certain health conditions or other factors could raise your risk of harm if you take Sinemet. In such cases, your doctor may not prescribe Sinemet for you. These are known as contraindications. The list below includes contraindications of Sinemet.

If you have closed-angle glaucoma. Sinemet can increase the pressure in your eyes. If you have closed-angle glaucoma, your doctor will likely not prescribe Sinemet. This is because Sinemet could increase the pressure in your eyes to a dangerous level. You can ask your doctor about other treatments that may be better options for you.

If you take certain monoamine oxidase inhibitor (MAOI) drugs. There are two types of MAOIs: selective and nonselective. Nonselective MAOIs are a group of antidepressants. Examples include isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate). Selective MAOIs are prescribed to treat depression and Parkinson’s disease. Examples include selegiline (Emsam, Zelapar) and rasagiline (Azilect).

If you take a nonselective MAOI, your doctor will likely not prescribe Sinemet. Taking these drugs together could cause a dangerous increase in blood pressure called a hypertensive crisis. Your doctor will also likely not prescribe Sinemet if you’ve taken a nonselective MAOI in the past 2 weeks. Your doctor can tell you about other treatments that may be better options for you.

If you take a selective MAOI, your doctor may prescribe Sinemet. However, taking these medications together could raise your risk of orthostatic hypotension. This is a drop in blood pressure that happens when you get up from sitting or lying down. It can make you feel dizzy, lightheaded, or faint.

If you’ve had an allergic reaction. If you have had an allergic reaction to Sinemet or any of its ingredients, your doctor likely won’t prescribe Sinemet. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better options for you.

Before you start taking Sinemet, talk with your doctor if any of the factors above apply to you. Your doctor can determine whether Sinemet is safe for you to take.

Does Sinemet interact with alcohol?

It may be best to avoid alcohol or limit the amount you drink while taking Sinemet. Sinemet and alcohol can cause some similar side effects, such as nausea, dizziness, and sleepiness. So you may be more likely to experience these side effects if you drink alcohol during your Sinemet treatment.

Sinemet can also cause some people to fall asleep suddenly without warning. This can happen during activities such as eating, talking, or driving. As alcohol can increase sleepiness, you’re more likely to have this side effect if you drink alcohol with Sinemet.

If you have questions about consuming alcohol while taking Sinemet, talk with your doctor or pharmacist.

Drug interactions explained

Learn more about certain drug interactions that can occur with Sinemet.

Interaction with blood pressure medications

Sinemet can interact with blood pressure medications, which are prescribed to treat high blood pressure. They’re commonly prescribed with Sinemet in people who have both high blood pressure and Parkinson’s disease.

Examples of blood pressure medications include:

• doxazosin (Cardura)
• indapamide
• losartan (Cozaar)
• propranolol (Inderal LA, Innopran XL)
• ramipril (Altace)

What could happen

Sinemet and blood pressure medications can both cause hypotension (low blood pressure). Taking these drugs together can raise your risk of orthostatic hypotension. This is a drop in blood pressure that happens when you get up from sitting or lying down. It can make you feel dizzy, lightheaded, or faint. This can raise your risk of falls.

What you can do

If you take Sinemet with a blood pressure medication, your doctor may prescribe a lower dosage of Sinemet or the blood pressure drug. You should not take a higher dose of either medication than your doctor prescribes.

If you take Sinemet with a blood pressure drug, be sure to move slowly when you get up from sitting or lying down. This can help prevent your blood pressure from suddenly dropping too low.

If you feel dizzy, lightheaded, or faint when you change position, you should sit or lie down until your symptoms go away. If you have these symptoms, tell your doctor. They may need to adjust your dosage of Sinemet or the blood pressure medication.

If you have questions about taking Sinemet with a blood pressure drug, talk with your doctor or pharmacist.

Interaction with tricyclic antidepressants (TCAs)

Sinemet can interact with TCAs, which are prescribed to treat depression and nerve pain.

Examples of tricyclic antidepressant medications:

• amitriptyline
• imipramine (Tofranil)
• nortriptyline (Pamelor)

What could happen

Taking Sinemet with a TCA may raise your risk of certain side effects from either drug. These include high blood pressure and dyskinesia (uncontrollable movements that may affect your whole body).

What you can do

If your doctor says you can take Sinemet with a TCA, they will likely monitor you for side effects during your treatment. You should not take a higher dose of either medication than your doctor prescribes.

Tell your doctor right away if you have symptoms of dyskinesia, such as involuntary, writhing movements of your face, arms, legs, or body.

Interaction with promethazine

Sinemet can interact with promethazine and combination medications that contain promethazine.

Promethazine is an antihistamine that causes sleepiness. It’s prescribed to treat allergies, cough, runny nose, and motion sickness.

What could happen

Sinemet and promethazine can both cause sleepiness. Taking Sinemet with promethazine can make you more likely to feel sleepy.

Sinemet can also cause some people to fall asleep suddenly without warning. This can happen during activities such as eating, talking, or driving. Because promethazine can also cause sleepiness, you’re more likely to have this side effect if you take Sinemet with promethazine.

Taking Sinemet with promethazine may also make Sinemet less effective at treating Parkinson’s symptoms. This is because promethazine can block some of Sinemet’s action in your brain.

What you can do

Your doctor will likely not prescribe Sinemet with promethazine. Talk with your doctor or pharmacist about other treatments that may be better options for you.

If you do take Sinemet with promethazine, tell your doctor right away if you have excessive sleepiness or suddenly fall asleep. You should also tell your doctor right away if your Parkinson’s symptoms get worse.

Are there other interactions with Sinemet?

Sinemet may have other interactions. They could occur with supplements, foods, vaccines, or even lab tests. See below for details. Note that the information below does not include all other possible interactions with Sinemet.

Does Sinemet interact with supplements?

Before you start taking Sinemet, talk with your doctor and pharmacist about any supplements, herbs, and vitamins you take. Sharing this information with them may help you avoid possible interactions.

If you have questions about other interactions that may affect you, talk with your doctor or pharmacist.

Sinemet and herbs

There are currently no reports of Sinemet interacting with herbs. But this doesn’t mean that interactions with herbs won’t be recognized in the future.

For this reason, it’s still important to check with your doctor or pharmacist before taking any of these products while taking Sinemet.

Sinemet interaction with vitamins and minerals

Sinemet can interact with iron supplements, including multivitamins that contain iron. Taking Sinemet with a supplement or multivitamin that contains iron can prevent your body from correctly absorbing Sinemet. This can make the drug less effective.

To avoid this interaction, you should not take Sinemet within 2 hours of taking supplements or multivitamins that contain iron. If you need to take Sinemet with one of these products, talk with your doctor or pharmacist about when to take your doses.

Does Sinemet interact with food?

You can take Sinemet with or without food. But Sinemet can interact with certain foods. For example, Sinemet can interact with foods that are high in protein, fat, or fiber.

Taking Sinemet with foods that are high in protein, fat, or fiber may cause your body to absorb the drug more slowly. This could mean that it takes Sinemet longer to start working. Taking Sinemet with these foods can also decrease the amount of Sinemet that gets absorbed into your body. This can make Sinemet less effective at treating your Parkinson’s symptoms.

Talk with your doctor about your diet. They can recommend the best time for you to take your Sinemet doses and whether you should take them with or without food. In addition, if you have questions about specific foods you should avoid with Sinemet, talk with your doctor.

Does Sinemet interact with vaccines?

There are currently no reports of Sinemet interacting with vaccines. If you have questions about getting certain vaccines during your Sinemet treatment, talk with your doctor.

Does Sinemet interact with lab tests?

Sinemet can interact with certain lab tests. For example, it can interact with:

• certain urine tests for ketones (a chemical your body produces when it breaks down fats instead of sugar for energy)
• certain urine tests for glucose (sugar)
• plasma and urine tests for epinephrine or norepinephrine (used to help diagnose adrenal gland disorders)

If you have questions about having certain lab tests done during your Sinemet treatment, talk with the healthcare professional ordering the test.

Does Sinemet interact with cannabis or CBD?

Cannabis (commonly called marijuana) and cannabis products, such as cannabidiol (CBD), have been specifically reported to interact with Sinemet.

Sinemet and cannabis can both cause sleepiness. So you may be more likely to feel sleepy or have episodes of suddenly falling asleep if you use cannabis while taking Sinemet. Your doctor will likely recommend that you avoid cannabis while you’re taking Sinemet.

Before you start treatment with Sinemet, tell your doctor and pharmacist if you use cannabis. By sharing this information with them, you may help prevent possible interactions.

Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.

Does my health history affect whether I should take Sinemet?

Certain medical conditions or other health factors may raise the risk of interactions with Sinemet. Before taking Sinemet, talk with your doctor about your health history. They’ll determine whether Sinemet is right for you.

Health conditions or other factors that might interact with Sinemet include:

Glaucoma. If you have a type of glaucoma called closed-angle glaucoma, your doctor will likely not prescribe Sinemet for you. This is because Sinemet can increase the pressure in your eyes, which could worsen glaucoma.

If you have open-angle glaucoma that’s effectively managed, your doctor may prescribe Sinemet for you. But they’ll likely recommend that you have your eye pressure checked more often than usual during your Sinemet treatment.

Mental health conditions. Sinemet can sometimes cause abnormal thinking or behavior. For example, it may cause paranoia, aggression, delusions, agitation, or hallucinations. If you have a mental health condition such as schizophrenia or bipolar disorder, Sinemet could make your condition worse. Your doctor will likely recommend a treatment other than Sinemet.

Heart disease. Sinemet can sometimes cause heart-related side effects, such as high or low blood pressure. If you have heart disease or have had a heart attack, Sinemet may not be safe for you. Talk with your doctor about other treatments that may be better options for you.

Peptic ulcer. If you’ve had a past peptic ulcer (sore in the lining of your stomach or small intestine), taking Sinemet could raise the risk of bleeding in your stomach or intestines. Talk with your doctor about whether Sinemet is safe for you.

Pregnancy. It’s not known whether Sinemet is safe to take during pregnancy. If you’re pregnant or planning a pregnancy, talk with your doctor before taking Sinemet.

Breastfeeding. It’s not known whether it’s safe to take Sinemet while breastfeeding. The drug passes into breast milk, but it isn’t known whether the drug may cause side effects in a child who is breastfed. If you’re breastfeeding or planning to breastfeed, talk with your doctor about your options.

Allergic reaction. If you’ve had an allergic reaction to Sinemet or any of its ingredients, your doctor will likely not prescribe Sinemet. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better choices for you.

How can I prevent interactions?

Taking certain steps can help you avoid interactions with Sinemet. Before starting treatment, talk with your doctor and pharmacist. Things to discuss with them include:

• Whether you drink alcohol or use cannabis.
• Other medications you take, as well as any vitamins, supplements, and herbs. Your doctor or pharmacist can help you fill out a medication list.
• What to do if you start taking a new drug during your Sinemet treatment.

It’s also important to understand Sinemet’s label and other paperwork that may come with the drug. Colored stickers that describe interactions may be on the label. And the paperwork (sometimes called the patient package insert or medication guide) may have other details about interactions. (If you did not get paperwork with Sinemet, ask your pharmacist to print a copy for you.)

If you have trouble reading or understanding this information, your doctor or pharmacist can help.

Taking Sinemet exactly as prescribed can also help prevent interactions.

What should I ask my doctor?

If you still have questions about Sinemet and its possible interactions, talk with your doctor.

Questions you may want to ask your doctor include:

• Does my risk of interactions with Sinemet depend on the dosage I’m prescribed?
• Do I need to tell you if I start taking another medication or supplement with Sinemet?
• Should I let you know if I make changes to my diet while taking Sinemet?
• Is it safe to take pain relievers with Sinemet?

To learn more about Sinemet, see these articles:

• All About Sinemet
• Side Effects of Sinemet: What You Need to Know
• Dosage Details for Sinemet: What You Need to Know

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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.