Levodopa and Carbidopa (patient information)

Why this medication is prescribed

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.

How this medication should be used

The combination of levodopa and carbidopa comes as a regular tablet, an orally disintegrating tablet, and an extended-release (long-acting) tablet to take by mouth. 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. 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 split, chew, or crush them.

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. The dose of the extended-release tablet may be gradually increased after 3 days as needed.

Levodopa and carbidopa controls Parkinson's disease but does 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.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Special 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. Ask your pharmacist for a list of the ingredients.
• tell your doctor if you are taking phenelzine (Nardil) or tranyllcypromine (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); papaverine (Pavabid); phenytoin (Dilantin); rasagiline (Azilect); risperidone (Risperdal); and selegiline (Eldepryl) .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 a 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; ulcers; heart attacks; irregular heartbeat; or blood vessel, heart, kidney, liver or lung disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. 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 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.
• 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 phenylalanine.

Special dietary instructions

Talk to your doctor if you plan on changing your diet to foods that are high in protein, such as meat, poultry, and dairy products.

What to do if you forget a dose

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Side effects

Minor side effects

Levodopa and carbidopa may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• dizziness
• nausea
• vomiting
• loss of appetite
• diarrhea
• dry mouth
• constipation
• change in sense of taste
• forgetfulness or confusion
• nervousness
• nightmares
• difficulty falling asleep or staying asleep
• headaches
• weakness
• increased sweating
• drowsiness

Severe side effects

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

• unusual or uncontrolled movements of the mouth, tongue, face, head, neck, arms, and legs
• fast, irregular, or pounding heartbeat
• depression
• 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
• hoarseness
• difficulty swallowing or breathing
• hives
• black and tarry stools
• red blood in stools
• bloody vomit
• vomiting material that looks like coffee grounds

Storage conditions needed for this medication

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Other information

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 its 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 TesTape) and ketones (Acetest, Ketostix, and Labstix). Diabetic patients should use TesTape to test urine for glucose (sugar); better results can be obtained by holding the tape vertically, inserting the lower portion of the tape into the urine sample, and reading the color at the top of the damp area.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription

Brand names

• Parcopa®
• Sinemet®
• Sinemet CR®
• Stalevo® (Levodopa and Carbidopa in combination with Entacapone)