Carbidopa/lev/entac 18.75-75-200mg
Overview
What is this medicine?
How to Use This Medicine
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food. Swallow the tablet whole - do not chew, break, or crush it.
If you take an iron supplement or a multivitamin that contains iron, consult your doctor or pharmacist about how to take it in relation to this medication. Iron may reduce the absorption of this medication in your body.
Your diet can also affect how well your body absorbs this medication. Diets high in protein, fat, or calories, as well as eating acidic foods, may reduce absorption. Discuss your diet with your doctor, especially if you plan to make any changes.
Do not stop taking this medication suddenly without consulting your doctor, as this may increase your risk of side effects. If you need to stop taking this medication, your doctor will instruct you on how to taper off gradually.
Continue taking this medication even when you are not experiencing symptoms. Keeping a diary of your symptoms can be helpful. Take this medication at the same time every day, as directed by your doctor or healthcare provider, even if you feel well.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, away from the bathroom. Keep all medications out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of your medication, consult your pharmacist. You may also want to check if there are any drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
Lifestyle & Tips
- Take exactly as prescribed. Do not stop taking it suddenly without consulting your doctor, as this can lead to serious withdrawal symptoms.
- You can take it with or without food. However, high-protein meals may reduce the absorption of levodopa, so discuss meal timing with your doctor.
- Be aware of potential dizziness or lightheadedness, especially when standing up quickly (orthostatic hypotension). Rise slowly from a sitting or lying position.
- Avoid driving or operating machinery if you experience drowsiness or sudden sleep episodes.
- Your urine, sweat, or saliva may turn reddish-brown or dark, which is a harmless effect of entacapone.
- Report any new or worsening involuntary movements (dyskinesias) or changes in mood/behavior (e.g., hallucinations, compulsive behaviors) to your doctor.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Condition-Specific Dosing:
Pediatric Dosing
Dose Adjustments
Renal Impairment:
Hepatic Impairment:
Pharmacology
Mechanism of Action
Pharmacokinetics
Absorption:
Distribution:
Elimination:
Pharmacodynamics
Safety & Warnings
Side Effects
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency medical attention:
Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
New or worsening behavior or mood changes, including:
+ Depression
+ Thoughts of suicide
Hallucinations (seeing or hearing things that are not there)
Severe dizziness or fainting
Confusion
Vomiting blood or coffee ground-like material
Black, tarry, or bloody stools
Muscle pain or weakness, dark urine, or difficulty urinating
A new skin lump or growth
Changes in the color or size of a mole
Strong, uncontrollable urges (such as eating, gambling, sex, or spending money)
New or worsening trouble controlling body movements
Chest pain or pressure
Shortness of breath
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling extremely tired or weak
Sudden, unexplained sleepiness, especially during activities like driving, eating, or talking
If you experience sudden sleepiness, do not drive or engage in activities that require alertness. Contact your doctor immediately.
Neuroleptic Malignant Syndrome (NMS)
NMS is a rare but potentially life-threatening condition that can occur when this medication is stopped suddenly or when the dose is lowered. If you experience any of the following symptoms, contact your doctor immediately:
Fever
Muscle cramps or stiffness
Dizziness
Severe headache
Confusion
Changes in thinking or behavior
Fast or irregular heartbeat
Excessive sweating
Other Possible Side Effects
Most people do not experience severe side effects, but some may occur. If you notice any of the following symptoms, contact your doctor if they bother you or do not go away:
Dizziness, drowsiness, tiredness, or weakness
Constipation, diarrhea, stomach pain, upset stomach, or vomiting
Dry mouth
Headache
Trouble sleeping
Back pain
This is not a comprehensive list of all possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe or persistent diarrhea
- Uncontrolled, involuntary movements (dyskinesias)
- New or worsening hallucinations, delusions, or confusion
- Unusual urges or behaviors (e.g., gambling, hypersexuality, binge eating)
- Excessive daytime sleepiness or sudden onset of sleep
- Severe dizziness or fainting spells
- Muscle stiffness, fever, or confusion (signs of neuroleptic malignant syndrome-like reaction, especially if stopped suddenly)
- Signs of liver problems (e.g., yellowing of skin/eyes, dark urine, persistent nausea/vomiting)
Before Using This Medicine
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
Certain health conditions, including:
+ Glaucoma
+ Skin lumps or growths
+ A history of skin cancer
* If you have taken specific antidepressant medications, such as isocarboxazid, phenelzine, or tranylcypromine, within the last 14 days. Taking this medication too soon after these drugs can lead to severe high blood pressure.
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist. They will help determine whether it is safe to take this medication with your existing health conditions and other medications. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
To minimize the risk of accidents, avoid driving and other activities that require alertness until you understand how this medication affects you. When changing positions, such as standing up from a sitting or lying down position, do so slowly to reduce the likelihood of dizziness or fainting. Be cautious when navigating stairs to prevent falls.
Regular blood tests and other laboratory evaluations are crucial to monitor your condition. Adhere to your doctor's schedule for these tests, and inform all healthcare providers and laboratory personnel that you are taking this medication, as it may interfere with certain lab results.
You may experience a decrease in the medication's effectiveness as the time approaches for your next dose. If this occurs and causes concern, discuss it with your doctor. It may take several months to achieve the full therapeutic effect of this medication.
Before consuming alcohol, using marijuana or other cannabis products, or taking prescription or over-the-counter medications that may impair your reactions, consult with your doctor.
You may notice a dark discoloration (red, brown, or black) in your saliva, urine, or sweat, which is harmless but may stain your clothing.
If you experience diarrhea or vomiting, consult your doctor promptly to prevent dehydration and electrolyte imbalances.
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe dyskinesias
- Agitation
- Confusion
- Insomnia
- Orthostatic hypotension
- Tachycardia
- Arrhythmias
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Management is supportive, including gastric lavage, IV fluids, and careful monitoring of vital signs and cardiac rhythm. Pyridoxine is not effective in reversing levodopa effects when carbidopa is present.
Drug Interactions
Contraindicated Interactions
- Non-selective monoamine oxidase (MAO) inhibitors (e.g., phenelzine, tranylcypromine) - risk of hypertensive crisis. Must be discontinued at least 2 weeks prior to starting.
Major Interactions
- Selective MAO-A inhibitors (e.g., moclobemide) - risk of hypertensive crisis.
- Antipsychotics (e.g., haloperidol, chlorpromazine) - may antagonize the effects of levodopa.
- Metoclopramide - may antagonize the effects of levodopa.
- Iron salts (ferrous sulfate, gluconate) - may reduce levodopa absorption.
- Dopamine D2 receptor antagonists (e.g., phenothiazines, butyrophenones, risperidone) - may worsen Parkinsonian symptoms.
- Isoniazid - may reduce levodopa efficacy.
Moderate Interactions
- Antihypertensive agents - increased risk of orthostatic hypotension.
- Tricyclic antidepressants (TCAs) - may increase risk of orthostatic hypotension and hypertension.
- Sympathomimetics (e.g., epinephrine, norepinephrine, dopamine) - increased risk of arrhythmias and hypertension.
- Other COMT inhibitors (e.g., tolcapone) - not recommended due to lack of additional benefit and potential for increased adverse effects.
Minor Interactions
- High-protein diet - may reduce levodopa absorption.
Monitoring
Baseline Monitoring
Rationale: To establish baseline and monitor for potential hematologic abnormalities (e.g., hemolytic anemia, leukopenia, thrombocytopenia) associated with levodopa.
Timing: Prior to initiation
Rationale: To establish baseline and monitor for potential hepatotoxicity, especially with entacapone.
Timing: Prior to initiation
Rationale: To assess baseline renal function, as elimination is partly renal.
Timing: Prior to initiation
Rationale: To assess for baseline orthostatic hypotension or cardiac arrhythmias.
Timing: Prior to initiation
Rationale: To establish baseline cognitive and psychiatric status.
Timing: Prior to initiation
Routine Monitoring
Frequency: At each visit, or as needed
Target: Optimal motor control with minimal dyskinesia
Action Threshold: Increased 'off' time, severe dyskinesia, or new onset of dyskinesia requires dose adjustment or addition of other therapies.
Frequency: Regularly, especially during dose titration
Target: Normotensive, minimal orthostatic drop
Action Threshold: Significant orthostatic hypotension (e.g., >20 mmHg systolic drop) requires dose adjustment or intervention.
Frequency: At each visit, or as needed
Target: Absence of new or worsening psychiatric symptoms
Action Threshold: New onset or worsening of symptoms requires dose adjustment or psychiatric evaluation.
Frequency: Periodically (e.g., every 6-12 months or as clinically indicated), especially if symptoms of liver dysfunction appear.
Target: Within normal limits
Action Threshold: Significant elevation (e.g., >3x ULN) requires investigation and potential discontinuation.
Frequency: Periodically (e.g., every 6-12 months or as clinically indicated).
Target: Within normal limits
Action Threshold: Significant abnormalities require investigation.
Frequency: Patient self-monitoring
Target: Normal
Action Threshold: Darkening of urine (harmless, due to entacapone metabolites) should be noted but does not require action unless accompanied by other symptoms.
Symptom Monitoring
- Orthostatic hypotension (dizziness, lightheadedness upon standing)
- Dyskinesia (involuntary movements)
- Nausea/vomiting
- Hallucinations, delusions, confusion
- Impulse control disorders (e.g., pathological gambling, hypersexuality, compulsive shopping, binge eating)
- Diarrhea (can be severe and persistent with entacapone)
- Sleepiness/sudden onset of sleep
- Darkening of urine, sweat, or saliva (harmless, due to entacapone metabolites)
Special Patient Groups
Pregnancy
Category C. Animal studies have shown adverse effects on fetal development. There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
Lactation
Levodopa is excreted in human milk. It is unknown if carbidopa or entacapone are excreted in human milk. Levodopa may inhibit lactation. Due to the potential for serious adverse reactions in breastfed infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Pediatric Use
Safety and effectiveness have not been established in pediatric patients. Not recommended for use in this population.
Geriatric Use
No specific dose adjustment is generally required based on age alone. However, elderly patients may be more sensitive to the adverse effects of levodopa, such as dyskinesias, hallucinations, and orthostatic hypotension. Initiate at the lower end of the dosing range and titrate carefully.
Clinical Information
Clinical Pearls
- This combination product is intended for patients already on carbidopa/levodopa who experience 'wearing-off' symptoms, not for initial Parkinson's therapy.
- Patients should be advised that their urine, sweat, and saliva may turn reddish-brown or dark due to entacapone metabolites, which is a harmless effect.
- Monitor for impulse control disorders (e.g., pathological gambling, hypersexuality, compulsive shopping, binge eating), which can occur with dopaminergic therapies.
- Diarrhea can be a significant side effect of entacapone; if severe or persistent, consider dose reduction or discontinuation.
- Sudden discontinuation can lead to a neuroleptic malignant syndrome-like reaction (fever, muscle rigidity, altered mental status, autonomic instability). Taper slowly if discontinuation is necessary.
- Advise patients to avoid sudden changes in posture to minimize orthostatic hypotension.
Alternative Therapies
- Dopamine agonists (e.g., pramipexole, ropinirole, rotigotine, apomorphine)
- MAO-B inhibitors (e.g., selegiline, rasagiline, safinamide)
- Amantadine
- Anticholinergics (e.g., benztropine, trihexyphenidyl)
- Adenosine A2A receptor antagonists (e.g., istradefylline)