Indications 

Sinemet is composed of a compound of carbidopa and levodopa, and serves as a pharmaceutical agent in the management of symptoms associated with Parkinson’s disease, including muscular rigidity, tremors, spasms, and compromised motor control.  

Parkinson’s disease pathophysiology is postulated to result from depleted levels of dopamine, a crucial neurotransmitter in the brain. Sinemet is indicated in the treatment of Parkinsonian symptoms secondary to carbon monoxide poisoning or manganese toxicity. 

Uses and Dosage 

Prior to initiating treatment with carbidopa/levodopa, review the Instructions for Use, if available, with their pharmacist. Subsequently, patients should review the instructions each time a prescription refill is obtained, and any related questions should be directed to the physician or pharmacist. 

This medication should be taken orally as directed by a healthcare provider, typically 3 to 4 times per day, with or without food. Ingestion of this medication with food may alleviate symptoms of nausea. However, a high-protein diet should be avoided, as it can impede levodopa absorption.  

In case of iron supplement use, the patient should separate their medication dose by as many hours as possible to ensure maximal medication absorption, as iron can reduce absorption of the medication. Healthcare providers may modify dosage regimens based on individual medical conditions and response to therapy, typically starting with a low dose and gradually increasing the dosage to minimize the occurrence of side effects. 

Use this medication consistently to achieve maximum benefit. Patients are advised to take it at the same time each day to help with adherence. In some cases, patients may experience a “wearing-off” phenomenon or an “on-off” effect where sudden short periods of stiffness occur.  

Patients are urged to report these symptoms to their healthcare provider for potential dose adjustments that may alleviate these effects. 

Patients should not abruptly discontinue this medication without consulting their physician. Abrupt cessation of this medication may exacerbate some conditions, and result in withdrawal symptoms such as depression, anxiety, fever, and muscle stiffness. Healthcare providers may choose to reduce dosage slowly to prevent withdrawal, particularly in patients who have used this medication for a prolonged period or in high doses. In case of any withdrawal symptoms, patients are urged to promptly notify their physician or pharmacist. 

Side Effects 

Allergic Reactions

Emergency medical help is required if you experience the following allergic reactions to Sinemet: 

• Hives 
• Difficulty in breathing 
• Swelling of the face, tongue, lips, or throat 

Severe Side Effects

Call your doctor immediately if you experience any of the following symptoms: 

• Uncontrolled facial muscle movements (including lip smacking, chewing, blinking, eye movement, frowning, or tongue movement) 
• Uncontrollable shaking (worsening of tremors) 
• Severe or continuous vomiting or diarrhea 
• Unusual mood changes or behavior 

• Confusion or hallucinations 
• Suicidal thoughts or depression 
• Very stiff muscles, fever, sweating, tremors, confusion, fast or uneven heartbeats, or feeling like passing out 

Inform your doctor if you experience excessive daytime sleepiness or drowsiness while taking Sinemet. 

Consult your doctor if you experience unusual urges to gamble, increased sexual urges, or other intense urges while taking Sinemet. 

Common Side Effects

It’s normal to experience dark-colored urine, saliva, or sweat, such as red, brown, or black, while taking Sinemet. However, it can stain your clothes or bed sheets. 

Some common side effects of Sinemet may include: 

• Jerky or twisting muscle movements 
• Headache, dizziness 
• Low blood pressure (feeling light-headed) 
• Sleep problems or unusual dreams 
• Dry mouth 
• Muscle contractions 
• Nausea, vomiting, or constipation 

Caution 

Before taking this medication, kindly inform your doctor or pharmacist about any allergic reactions to carbidopa or levodopa, or any other allergies you may have. This medication may include inactive components that could lead to allergic reactions or other issues. Please seek advice from your pharmacist for more details. 

Before using this medication, please inform your doctor or pharmacist of your medical history, particularly if you have a history of liver disease, glaucoma, breathing problems such as asthma, heart disease, irregular heartbeat, kidney disease, stomach or intestinal ulcer, mental or mood disorders like depression, schizophrenia, blood disorders, seizures, or sleep disorders. 

This medication may cause dizziness or drowsiness. Consumption of alcohol or marijuana (cannabis) may increase dizziness or drowsiness. Please refrain from driving, operating machinery or engaging in activities that require alertness until you can do them safely. Limit alcohol intake and consult your doctor if you are using marijuana (cannabis). Please refer to the Side Effects section as well. 

Before undergoing surgery, kindly inform your doctor or dentist about all the products you are using, including prescription drugs, non-prescription drugs, and herbal products. 

During pregnancy, this medication should only be used if clearly required. Please discuss the potential risks and benefits with your doctor. 

Levodopa passes into breast milk in small quantities and may affect milk production. The passage of carbidopa into breast milk is unknown. Kindly consult your doctor before breastfeeding.