The combination of levodopa and carbidopa is used to treat the symptoms of Parkinson’s disease and Parkinson’s-like symptoms that may develop after encephalitis (swelling of the brain) or injury to the nervous system caused by carbon monoxide poisoning or manganese poisoning. Parkinson’s symptoms, including tremors (shaking), stiffness, and slowness of movement, are caused by a lack of dopamine, a natural substance usually found in the brain. Levodopa is in a class of medications called central nervous system agents. It works by being converted to dopamine in the brain. Carbidopa is in a class of medications called decarboxylase inhibitors. It works by preventing levodopa from being broken down before it reaches the brain. This allows for a lower dose of levodopa, which causes less nausea and vomiting.
Side Effects Of Levodopa and Carbidopa
Levodopa and carbidopa may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- loss of appetite
- dry mouth
- mouth and throat pain
- change in sense of taste
- forgetfulness or confusion
- difficulty falling asleep or staying asleep
Some side effects can be serious. If you experience any of the following symptoms or those listed in the WARNINGS AND PRECAUTIONS section, call your doctor immediately or get emergency medical treatment:
- unusual or uncontrolled movements of the mouth, tongue, face, head, neck, arms, and legs
- fast, irregular, or pounding heartbeat
- increased sweating
- chest pain
- thoughts of death or killing oneself
- hallucinating (seeing things or hearing voices that do not exist)
- swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
- difficulty swallowing or breathing
- weakness, numbness, or loss of sensation in the fingers or feet
- drainage, redness, swelling, pain, or warmth in the area around your PEG-J tube (if you are taking levodopa and carbidopa suspension)
- black and tarry stools
- red blood in stools
- abdominal pain
- bloody vomit
- vomit that looks like coffee grounds
Warnings & Precautions
Before taking levodopa and carbidopa:
- tell your doctor and pharmacist if you are allergic to levodopa and carbidopa any other medications, or any of the ingredients in levodopa and carbidopa tablets, capsules, or suspension. Ask your pharmacist for a list of the ingredients.
- tell your doctor if you are taking phenelzine (Nardil) or tranylcypromine (Parnate) or if you have stopped taking them in the past 2 weeks. Your doctor will probably tell you not to take levodopa and carbidopa.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antidepressants (‘mood elevators’) such as amitriptyline (Elavil), amoxapine (Asendin), clomipramine (Anafranil), desipramine (Norpramin), doxepin (Adapin, Sinequan), imipramine (Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil); antihistamines; haloperidol (Haldol); ipratropium (Atrovent); iron pills and vitamins containing iron; isocarboxazid (Marplan); isoniazid (INH, Nydrazid); medications for high blood pressure, irritable bowel disease, mental illness, motion sickness, nausea, ulcers, or urinary problems; metoclopramide (Reglan); other medications for Parkinson’s disease; papaverine (Pavabid); phenytoin (Dilantin); rasagiline (Azilect); risperidone (Risperdal); sedatives; selegiline (Emsam, Eldepryl, Zelapar); sleeping pills; tetrabenazine (Xenazine); and tranquilizers. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had glaucoma, melanoma (skin cancer), or skin growth that has not been diagnosed. Your doctor may tell you not to take levodopa and carbidopa.
- tell your doctor if you have or have ever had hormone problems; asthma; emphysema; mental illness; diabetes; stomach ulcers; heart attacks; an irregular heartbeat; or blood vessel, heart, kidney, liver, or lung disease. If you are using levodopa and carbidopa suspension, also tell your doctor if you have or have ever had stomach surgery, nerve problems, low blood pressure, or fainting.
- tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking levodopa and carbidopa, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking levodopa and carbidopa.
- you should know that levodopa and carbidopa may make you drowsy or may cause you to suddenly fall asleep during your regular daily activities. You might not feel drowsy or have any other warning signs before you suddenly fall asleep. Do not drive a car, operate machinery, work at heights, or participate in potentially dangerous activities at the beginning of your treatment until you know how the medication affects you. If you suddenly fall asleep while you are doing something such as watching television, talking, eating, or riding in a car, or if you become very drowsy, especially during the daytime, call your doctor. Do not drive, work in high places, or operate machinery until you talk to your doctor.
- ask your doctor about the safe use of alcoholic beverages while you are taking levodopa and carbidopa. Alcohol can make the side effects of levodopa and carbidopa worse.
- you should know that some people who took medications such as levodopa and carbidopa developed gambling problems or other intense urges or behaviors that were compulsive or unusual for them, such as increased sexual urges or behaviors. There is not enough information to tell whether the people developed these problems because they took the medication or for other reasons. Call your doctor if you have an urge to gamble that is difficult to control, you have intense urges, or you are unable to control your behavior. Tell your family members about this risk so that they can call the doctor even if you do not realize that your gambling or any other intense urges or unusual behaviors have become a problem.
- you should know that while taking levodopa and carbidopa, your saliva, urine, or sweat may become a dark color (red, brown, or black). This is harmless, but your clothing may become stained.
- you should know that levodopa and carbidopa may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking levodopa and carbidopa. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.
- if you have phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent mental retardation), you should know that the orally disintegrating tablets contain aspartame that forms phenylalanine.
Levodopa and Carbidopa Dosage
The combination of levodopa and carbidopa comes as a regular tablet, an orally disintegrating tablet, an extended-release (long-acting) tablet, and an extended-release (long-acting) capsule to take by mouth. The combination of levodopa and carbidopa also comes as a suspension (liquid) to be given into your stomach through a PEG-J tube (a tube surgically inserted through the skin and stomach wall) or sometimes through a naso-jejunal tube (NJ; a tube inserted into your nose and down to your stomach) using a special infusion pump. The regular and orally disintegrating tablets are usually taken three or four times a day. The extended-release tablet is usually taken two to four times a day. The extended-release capsule is usually taken three to five times a day. The suspension is usually given as a morning dose (given by infusion over 10 to 30 minutes) and then as a continuous dose (given by infusion over 16 hours), with extra doses given no more than once every 2 hours as needed to control your symptoms. Take levodopa and carbidopa at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take levodopa and carbidopa exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Swallow the extended-release tablets whole; do not chew or crush them.
Swallow the extended-release capsules whole; do not chew, divide, or crush them. Take the first daily dose of the extended-release capsule 1 to 2 hours before eating. If you have trouble swallowing, you can carefully open the extended-release capsule, sprinkle the entire contents on 1 to 2 tablespoons (15 to 30 mL) of apple sauce, and consume the mixture immediately. Do not store the mixture for future use.
To take the orally disintegrating tablet, remove the tablet from the bottle using dry hands and immediately place it in your mouth. The tablet will quickly dissolve and can be swallowed with saliva. No water is needed to swallow disintegrating tablets.
If you are switching from levodopa (Dopar or Larodopa; no longer available in the US) to the combination of levodopa and carbidopa, follow your doctor’s instructions. You will probably be told to wait at least 12 hours after your last dose of levodopa to take your first dose of levodopa and carbidopa.
Your doctor may start you on a low dose of levodopa and carbidopa and gradually increase your dose of the regular or orally disintegrating tablet every day or every other day as needed. Your doctor may gradually increase your dose of the extended-release tablet or capsule after 3 days as needed.
To take the suspension, your doctor or pharmacist will show you how to use the pump to give your medication. Read the written instructions that come with the pump and the medication. Look at the diagrams carefully and be sure that you recognize all the parts of the pump and the description of the keys. Ask your doctor or pharmacist to explain any part you do not understand.
Levodopa and carbidopa suspension comes in a single-use cassette to connect to the pump that will control the amount of medication you will receive during your infusion. Before use, remove the cassette containing the medication from the refrigerator and allow it to sit at room temperature for 20 minutes. Do not reuse a cassette or use it for longer than 16 hours. Dispose of the cassette at the end of the infusion even if it still contains the medication.
When you begin taking levodopa and carbidopa suspension, your doctor will adjust your morning and continuous infusion doses and possibly the doses of your other Parkinson’s disease medications to best control your symptoms. It usually takes about 5 days to reach a stable dose of the suspension, but your doses may need to be changed again over time depending on your ongoing response to the medication. Your prescribed dose of the suspension will be programmed into your pump by your doctor. Do not change the dose or settings on your pump unless you are told to do so by your doctor. Be careful to make sure your PEG-J tube does not become kinked, knotted, or blocked as this will affect the amount of medication that you receive.
Levodopa and carbidopa control Parkinson’s disease but do not cure it. It may take several months before you feel the full benefit of levodopa and carbidopa. Continue to take levodopa and carbidopa even if you feel well. Do not stop taking levodopa and carbidopa without talking to your doctor. If you suddenly stop taking levodopa and carbidopa, you could develop a serious syndrome that causes fever, rigid muscles, unusual body movements, and confusion. Your doctor will probably decrease your dose gradually. If your doctor tells you to stop taking levodopa and carbidopa suspension, a healthcare professional will remove your PEG-J tube; do not remove the tube yourself.
Ask your pharmacist or doctor for a copy of the manufacturer’s patient information sheet for levodopa and carbidopa and also the Medication Guide for levodopa and carbidopa suspension.
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to levodopa and carbidopa.
Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking levodopa and carbidopa.
Levodopa and carbidopa can lose their effect completely over time or only at certain times during the day. Call your doctor if your Parkinson’s disease symptoms (shaking, stiffness, and slowness of movement) worsen or vary in severity.
As your condition improves and it is easier for you to move, be careful not to overdo physical activities. Increase your activity gradually to avoid falls and injuries.
Levodopa and carbidopa can cause false results in urine tests for sugar (Clinistix, Clinitest, and Tes-Tape) and ketones (Acetest, Ketostix, and Labstix).
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.