Sinemet CR

Generic name: Carbidopa with levodopa.

Sinemet CR is an antiparkinsonism agent. It corrects the chemical imbalance, thereby relieving symptoms of Parkinson’s disease. Levodopa treats the Parkinson’s symptoms, and carbidopa prevents vitamin B6 from destroying the levodopa.

Quick Facts About Sinemet CR


Used to treat the symptoms of Parkinson’s disease — muscle stiffness, tremor, and weakness. Also used to treat similar symptoms caused by encephalitis (brain fever), carbon monoxide poisoning, or manganese poisoning.

Sinemet CR Dosage

Take after meals, swallowing tablets whole; do not chew or crush tablets. Important to take dose at the same time each day; most effective with a constant level in the blood. Only doctor should change dose or add other Parkinson’s disease products to the therapy program. Do not abruptly discontinue medication; may result in muscle rigidity, high temperature, and mental changes.

  • Usual adult dose: for mild to moderate symptoms — 1 tablet taken 2 times per day. Initially, doses should be every 4 to 8 hours, then adjusted to each patient’s needs. Long-term dose is 2 to 8 tablets per day taken in divided doses every 4 to 8 hours while awake.
  • Usual child dose: not generally prescribed for children.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Sinemet CR Side Effects

Overdose symptoms:

muscle twitches, inability to  open the eyes. If you suspect an overdose, immediately seek medical attention.

More common side effects: confusion, hallucinations, nausea, uncontrollable jerking or twitching.

Less common  or rare Sinemet CR side effects: abdominal or stomach pain, abnormal dreams, agitation, anemia, anxiety, back pain, bitter taste, bizarre breathing patterns, bleeding from stomach, blurred vision, burning sensation on tongue, chest pain, clumsiness in walking, common cold, constipation, convulsions, cough, dark sweat, dark urine, delusions, depression, diarrhea, disorientation, dizziness, dizziness upon standing, dream abnormalities, drooling, drowsiness, dry mouth, euphoria, eyelid twitching, faintness, falling, fatigue, fever, flatulence, fluid retention, flushing, hair loss, headache, heart attack, heart palpitations, heartburn, hiccups, high or low blood pressure, hoarseness, hot flashes, increased hand tremor, insomnia or other sleep disorders, irregular heartbeat, leg pain, locked jaw, loss of appetite, malignant melanoma, memory problems, mental changes, muscle cramps, muscle twitching, nervousness, numbness, “on-off” phenomena, paralysis of certain muscles and unwanted movement of others, paranoia, persistent erection, phlebitis (vein swelling), rash, shortness of breath, shoulder pain, slowed physical movements, sore throat, speech impairment, stomach ulcer, suicidal tendencies, swallowing difficulties, sweating, teeth-grinding, tingling or pins and needles, upper respiratory infection, upset stomach, urinary frequency, urinary incontinence, urinary retention, urinary tract infections, weakness, weight loss or gain, writhing or flailing movements, vomiting.


Inform your doctor before combining Sinemet CR with:

antacids such as Di-Gel and Maalox, anticonvulsants such as Dilantin, antiparkinson medications such as Artane and Cogentin, antihypertensives such as Aldomet and Clonidine, iron products such as Feosol, isoniazid (Nydrazid), major tranquilizers such as Haldol and Thorazine, MAO inhibitors such as Nardil and Parnate, methionine medications such as Odor-Scrip and Pedameth, metoclopramide (Reglan), papaverine (Pavabid), pyridoxine (Vitamin B6), tranquilizers such as Valium and Xanax, tricyclic antidepressants such as Elavil and Tofranil. Must discontinue MAO inhibitors at least 2 weeks prior to starting Sinemet CR therapy.

No known food/other substance interactions.

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Not known if Sinemet CR appears in breast milk.

No special precautions apply to seniors.

Not generally prescribed for children.

  • Do not take if sensitive to or allergic to Sinemet CR.
  • Doctor should not prescribe if you have an undiagnosed mole or history of melanoma.
  • Inform your doctor before starting Sinemet CR therapy if you have: bronchial asthma, cardiovascular or lung disease, endocrine (gland) disorder, history of heart attack or heartbeat irregularity, history of active peptic ulcer, kidney or liver disorder, wide-angle glaucoma.
  • Sinemet is a regular, noncontrolled form of Sinemet CR. If taking regular Sinemet, may need higher dose of Sinemet CR to get same kind of relief, and may take longer to start working than the first morning dose of regular Sinemet
  • Doctor should monitor blood, liver, heart, and kidney during long-term Sinemet CR therapy.
  • If taking levodopa alone, discontinue it for at least 8 hours before starting Sinemet CR.
  • Carbidopa ingredient in Sinemet CR will not eliminate levodopa side effects. May produce levodopa side effects, since it helps levodopa reach the brain. Doctor may reduce dose if you experience involuntary movement side effects.
  • May cause depression: inform your doctor if you have any mental or emotional problems.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Sinemet CR side effects, please contact your healthcare provider