How does this medication work? What will it do for me?
This is a combination product containing two medications: levodopa and carbidopa. It is used to treat Parkinson's disease.
Levodopa helps to control the symptoms of Parkinson's disease by correcting the chemical imbalance in the brain that produces symptoms. Levodopa can be used alone, but adding carbidopa lowers the amount of levodopa that is required and may reduce some of the side effects that are associated with levodopa, such as nausea and vomiting.
Although levodopa helps relieve symptoms of Parkinson's disease, it does not slow down the progression of the disease.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Sinemet is no longer being manufactured for sale in Canada. For brands that may still be available, search under levodopa-carbidopa. This article is being kept available for reference purposes only. If you are using this medication, speak with your doctor or pharmacist for information about your treatment options.
How should I use this medication?
Treatment with levodopa - carbidopa should be started slowly and increased gradually to reduce the risk of side effects while gaining maximum benefit from the medication.
The recommended starting dose for people not already taking levodopa is 1 tablet, containing 100 mg of levodopa and 25 mg of carbidopa, 3 times a day. Your doctor will usually increase the dosage by 1 tablet daily every 3 days until the best results occur with the least amount of side effects. When the dose rises above 3 tablets daily, the dose should be divided into 4 to 6 daily doses. The maximum daily dose of levodopa is 1,500 mg.
If you have already been taking levodopa and are starting levodopa - carbidopa, the dose will be much lower than the dose of levodopa taken as a single medication.
Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
The controlled release (CR tablets) form of this medication should be swallowed whole with fluids. Do not crush or chew the medication as this will destroy the time-release property of the medication.
It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and continue on with your regular schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice. If you miss more than one dose, check with your doctor.
Store this medication at room temperature, and protect it from light and moisture. Keep it out of the reach of children.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Do not take levodopa - carbidopa if you:
- are allergic to levodopa, carbidopa, or any ingredients of the medication
- cannot take sympathomimetic amines (e.g., epinephrine, norepinephrine)
- have active heart disease, blood related diseases, endocrine disease, liver disease, lung disease, or kidney disease
- have narrow-angle glaucoma
- have suspicious undiagnosed skin lesions or a history of melanoma
- have used an MAO inhibitor (e.g., phenelzine, tranylcypromine) within the past 2 weeks (MAO inhibitors should not be used within 2 weeks after taking levodopa - carbidopa)
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.
The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- burning sensation on the tongue
- change in colour of urine, saliva, or sweat
- changed sense of taste
- dry mouth
- hair loss
- grinding or clenching teeth
- leg pain
- loss of appetite
- muscle twitching
- slowed movement
- trouble sleeping
- weight changes
Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- abnormal thinking – holding false beliefs that cannot be changed by fact
- blood pressure changes (increase and decrease)
- blurred or double vision
- compulsive behaviour (e.g., gambling, spending, increased sexual urges)
- difficulty swallowing
- dilated (large) pupils
- dizziness or lightheadedness when rising from a lying or sitting position
- double vision
- fast, irregular, or pounding heartbeat
- hallucinations (e.g., seeing or hearing things that are not there)
- hand tremor (increased)
- mood or mental changes
- patches of discolouration on the skin
- signs of bleeding in the stomach (e.g., bloody, black, or tarry stools; spitting up of blood; vomiting blood or material that looks like coffee grounds)
- signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
- signs of infection (fever, severe chills, sore throat, or mouth ulcers)
- skin changes (e.g., sores, warts, or bumps that do not heal)
- spasms that move the eye into a fixed position
- sudden onset of sleep
- symptoms of a urinary tract infection (e.g. pain when urinating, urinating more often than usual, low back or flank pain)
- unusual and uncontrolled movements of the body, including face, tongue, arms, hands, head, and upper body
Stop taking the medication and seek immediate medical attention if any of the following occur:
- long-lasting (more than 4 hours) and painful erection
- signs of neuroleptic malignant syndrome (e.g., confusion, reduced consciousness, high fever, or muscle stiffness)
- signs of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
- signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
- thoughts of self harm or suicide
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take this medication.
Behaviour and mood changes: This medication has been known to cause mood swings, changes in behaviour, and symptoms of depression. If you have depression or a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. You may notice compulsive behaviour, such as gambling, increased sexual activity, or inappropriate spending. Levodopa-carbidopa has been associated with hallucinations and confusion. If you experience these side effects, contact your doctor.
Bleeding: Levodopa - carbidopa may cause a reduced number of platelets in the blood, which can make it difficult to stop cuts from bleeding. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, or black and tarry stools, notify your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early.
Blood pressure and heart: This medication can cause blood pressure changes, making symptoms of heart conditions worse. If you have heart disease (e.g., history of heart attack, arrhythmia), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Some people taking levodopa-carbidopa experience sudden blood pressure drops when getting up from a sitting or lying position. These blood pressure drops could lead to dizziness, lightheadedness, and falls. If you experience this problem, try getting up more slowly. If it persists or if you faint, contact your doctor.
Depression: This medication has been known to cause mood swings and symptoms of depression. If you have depression or a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking this medication, contact your doctor as soon as possible.
Drowsiness/dizziness: Levodopa - carbidopa may cause drowsiness, dizziness, or affect mental abilities necessary to drive or operate machinery. Avoid activities that that require alertness until you know how this medication affects you.
Glaucoma: This medication may cause symptoms of glaucoma to get worse by increasing the pressure inside the eye. If you have chronic wide-angle glaucoma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
High-protein diet: Levodopa competes with certain amino acids for absorption into the body. As a result, some patients on a high-protein diet may have reduced absorption of levodopa. It is important to not change your diet dramatically when you are taking this medication, as this may change how well the medication works for you.
Infection: Levodopa - carbidopa has been reported to reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people who have contagious infections. Tell your doctor immediately if you notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.
Melanoma: People with Parkinson's disease may be at increased risk of developing melanoma (a type of skin cancer). It is not known if this increased risk is due to Parkinson's disease or to the medications used to treat Parkinson's disease. Your doctor will monitor you for skin cancer while you are taking this medication. Talk to your doctor if you have any concerns.
Neuroleptic malignant syndrome (NMS): Very rarely, levodopa - carbidopa can cause a potentially fatal syndrome known as neuroleptic malignant syndrome (NMS). If you notice the symptoms of NMS such as high fever, muscle stiffness, confusion or loss of consciousness, sweating, racing or irregular heartbeat, or fainting, get immediate medical attention.
Peptic (stomach) ulcer: There is a possibility of stomach bleeding for people with a history of peptic ulcer who take levodopa - carbidopa. If you have peptic ulcers or a history of peptic ulcers, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you notice bloody or black tarry stools, stomach pain, vomiting blood or material that looks like coffee grounds, contact your doctor immediately.
Physical activity: People whose symptoms improve while on therapy with levodopa - carbidopa should increase their physical activities gradually and with caution.
Seizures: If you have seizures or a history of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Sudden onset of sleep: There are reports of people who take levodopa - carbidopa combinations falling asleep with no warning or drowsiness. If you have a sleep disorder, discuss this with your doctor. If you experience drowsiness while taking this medication, avoid driving or using machinery.
Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: Levodopa passes into breast milk. It is not known if carbidopa passes into breast milk. If you are a breast-feeding mother and are taking levodopa - carbidopa, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of levodopa - carbidopa have not been established for use by people under 18 years of age.
What other drugs could interact with this medication?
There may be an interaction between levodopa - carbidopa and any of the following:
- alpha-agonists (e.g., clonidine, methyldopa)
- alpha-blockers (e.g., alfuzosin, doxazosin, tamsulosin)
- angiotensin converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
- angiotensin receptor blockers (ARBs; e.g., candesartan, irbesartan, losartan)
- antipsychotics (e.g., chlorpromazine, haloperidol, quetiapine, risperidone)
- beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
- calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
- diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
- iron salts (e.g., ferrous sulfate)
- kava kava
- MAO inhibitors (e.g., phenelzine, moclobemide, selegiline, tranylcypromine)
- multivitamins with minerals (vitamins A, D, E, K)
- nitrates (e.g., nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
- phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
- tretinoin (systemic)
- tricyclic antidepressants (e.g., amitriptyline, desipramine)
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.
All material copyright MediResource Inc. 1996 – 2023. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/drug/getdrug/Sinemet