This combination medication is used to treat symptoms of Parkinson's disease or Parkinson-like symptoms (such as shakiness, stiffness, difficulty moving). Parkinson's disease is thought to be caused by too little of a naturally occurring substance (dopamine) in the brain. Levodopa changes into dopamine in the brain, helping to control movement. Carbidopa prevents the breakdown of levodopa in the bloodstream so more levodopa can enter the brain. Carbidopa can also reduce some of levodopa's side effects such as nausea and vomiting.
Take this medication by mouth with or without food as directed by your doctor, usually 3 to 4 times a day. Taking this medication with food may help to decrease nausea. It is best to avoid a high-protein diet (it decreases the amount of levodopa that your body takes in) during treatment, unless directed otherwise by your doctor. Separate your dose of this medication by as many hours as possible from any iron supplements or products containing iron (such as multivitamins with minerals) you may take. Iron can reduce the amount of this medication absorbed by the body. Consult your doctor or pharmacist for more details. The dosage is based on your medical condition and response to treatment. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully. This combination medication comes in different strengths with different amounts of carbidopa and levodopa in each tablet. Be sure you have the correct strength of both drugs. Your doctor may also prescribe carbidopa alone to be taken with this combination. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day. Some patients may experience a "wearing-off" (worsening of symptoms) before the next dose is due. An "on-off" effect might also occur, in which sudden short periods of stiffness occur. If these effects occur, contact your doctor for possible dose adjustments that may help to lessen this effect. Do not stop taking this medication without consulting your doctor. Some conditions may become worse when this drug is quickly reduced or suddenly stopped. Your dose may need to be gradually reduced. (See also Side Effects section.) Tell your doctor if your condition does not improve or if it worsens.
Dizziness, lightheadedness, nausea, vomiting, loss of appetite, trouble sleeping, unusual dreams, or headache may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. This medication may cause saliva, urine, or sweat to turn a dark color. This effect is harmless, but your clothes may be stained. To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Some people taking this medication have fallen asleep suddenly during their usual daily activities (such as talking on the phone, driving). In some cases, sleep occurred without any feelings of drowsiness beforehand. This sleep effect may occur anytime during treatment with carbidopa/levodopa even if you have used this medication for a long time. If you experience increased sleepiness or fall asleep during the day, do not drive or do other possibly dangerous activities until you have discussed this effect with your doctor. Your risk of this sleep effect is increased by using alcohol or other medications that can make you drowsy. See also Precautions section. Tell your doctor right away if you have any serious side effects, including: new/worsening movements you can't control/spasms, greatly increased eye blinking/twitching, fainting, vision changes (such as blurred vision, double vision), eye pain, severe stomach/abdominal pain, black/tarry stools, vomit that looks like coffee grounds, mental/mood changes (such as agitation, hallucinations, depression, thoughts of suicide), signs of infection (such as sore throat that doesn't go away), easy bleeding/bruising, unusual tiredness, tingling of the hands/feet, unusual strong urges (such as increased gambling, increased sexual urges). Get medical help right away if you have any very serious side effects, including: chest pain. Abruptly stopping or reducing the dose of this medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms: fever, unusual muscle stiffness, severe confusion, sweating, fast/irregular heartbeat, rapid breathing. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
See also How to Use section. Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: antipsychotic drugs (such as chlorpromazine, haloperidol, thioridazine), certain drugs used to treat high blood pressure (such as methyldopa). Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. However, certain MAO inhibitors (rasagiline, safinamide, selegiline) may be used with careful monitoring by your doctor. Ask your doctor when to start or stop taking this medication. This medication may interfere with certain laboratory tests (including urine catecholamine/glucose/ketone tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe dizziness, irregular heartbeat, mental/mood changes (such as agitation).