Sinemet (Carbidopa/Levodopa)

Description

Sinemet is a medication that combines two ingredients: Carbidopa and Levodopa. It is mainly used to help people with Parkinson's disease, a condition that causes symptoms like muscle stiffness, shaking, and difficulty with movement. Carbidopa helps make levodopa work better. Levodopa is changed into a chemical called dopamine in the brain, which helps reduce the symptoms caused by not having enough dopamine in people with Parkinson's. Sinemet helps manage these movement problems by providing the brain with the dopamine it needs, but it does not cure Parkinson's disease.

Directions

Sinemet is typically started at a dosage of 25 mg of Carbidopa and 100 mg of Levodopa taken three times per day. However, the standard Sinemet dosage may vary. Doctors may adjust the dosage depending on how well the person responds and tolerates the treatment. Swallow these tablets whole and do not crush or chew them. Consult a healthcare provider for further dosage instructions.

Ingredients

The active ingredients in Sinemet are Carbidopa and Levodopa.

Contraindications

Avoid taking or using this medication if any of the following apply:

• Known hypersensitivity to Carbidopa, Levodopa, or any components of the formulation
• Concurrent use of non-selective monoamine oxidase (MAO) inhibitors or use within the last 14 days

Cautions

• Before starting Sinemet, tell your healthcare provider about the following:
• Any existing health conditions
• Any allergies
• A list of all medications you are currently taking
• Whether you are pregnant or breastfeeding
• If you are already taking Levodopa, you must stop it at least 12 hours before starting Sinemet. Your doctor will adjust your dose to reduce side effects like nausea and vomiting.
• Sinemet can lead to depression and, in some cases, suicidal thoughts. If you experience mood changes, talk to your doctor right away. People with a history of major psychiatric conditions should use Sinemet cautiously.
• If you have severe heart or lung disease, asthma, or a history of a heart attack, Sinemet should be used with caution. Your doctor may monitor your heart, especially during the initial dose adjustments.
• Sinemet may cause a sudden drop in blood pressure, leading to dizziness or fainting. This risk is higher in people taking blood pressure medications. Tell your doctor if you experience symptoms of low blood pressure.
• Sinemet can cause sudden sleep episodes without warning, even during activities like driving. If this happens, stop driving or operating machinery and talk to your doctor. You may need to adjust your dose or discontinue the medication.
• Abruptly stopping Sinemet or reducing your dose can cause a rare but serious condition called neuroleptic malignant syndrome (NMS). Symptoms include fever, muscle stiffness, confusion, and irregular heartbeat. Seek immediate medical attention if these symptoms occur.
• Sinemet may lead to compulsive behaviors like excessive gambling, spending, or eating. If you notice unusual urges, talk to your doctor. Reducing the dose or stopping the medication can often resolve these issues.
• Patients with Parkinson’s disease have a higher risk of developing melanoma. Regular skin checks by a dermatologist are recommended while taking Sinemet.
• Sinemet can interact with certain medications, including MAO inhibitors, antidepressants, and blood pressure drugs, which might increase side effects. Let your doctor know about all medications and supplements you are taking.
• Sinemet may affect certain lab tests, including those for kidney function and urinary ketones. Inform your healthcare provider about your medication if you are undergoing testing.

Side Effects

The most common side effects of Sinemet include involuntary movements such as dyskinesias (choreiform or dystonic movements) and nausea. Other frequently reported symptoms are dizziness, dry mouth, and dark-colored saliva, sweat, or urine. Gastrointestinal problems such as diarrhea, constipation, and taste changes may also occur.

Sinemet can cause serious side effects like psychotic episodes, severe depression with suicidal thoughts, or impulse control issues such as pathological gambling or hypersexuality. Rare but significant adverse reactions include cardiovascular irregularities, gastrointestinal bleeding, and allergic reactions like angioedema or rash. If you experience severe mood changes, chest pain, or difficulty breathing, contact your healthcare provider immediately.

References

1. Sinemet (Carbidopa/Levodopa) Product Monograph. Whitehouse Station, NJ: Merck & Co., Inc.; 2020.
2. Sinemet (Carbidopa/Levodopa) Drug Label Information. Jersey City, NJ: Organon LLC; 2021.

About Dr. Gerardo Sison (Page Author)

An honors graduate of the University of Florida, Dr. Sison started his pharmacy career in a community setting, extending his services to hospitals and clinics over time. He has also worked in medication therapy management, advising patients on proper medication use for their chronic health conditions. Read More....