Carbidopa-levodopa is a commonly prescribed medication for treating the motor symptoms of Parkinson’s disease. It works by increasing dopamine levels in the brain, which helps improve movement and coordination. However, stopping carbidopa-levodopa can lead to complications for some Parkinson’s patients. In this article, we will explore what happens when you stop taking carbidopa-levodopa and why it is usually inadvisable to abruptly discontinue this medication without medical supervision.
What is Carbidopa-Levodopa?
Carbidopa-levodopa (also known as co-careldopa or Sinemet) is the most effective medication currently available for managing the motor symptoms of Parkinson’s disease. It contains two active ingredients:
- Carbidopa – Inhibits the breakdown of levodopa before it reaches the brain
- Levodopa – The precursor of dopamine which is converted into dopamine in the brain
By preventing levodopa breakdown outside the brain and increasing dopamine concentration in the brain, carbidopa-levodopa can significantly improve motor symptoms in Parkinson’s patients including bradykinesia (slow movement), rigidity, tremors, and gait/balance problems.
Carbidopa-levodopa is available in standard-release and longer-acting extended-release formulations. The standard version is taken every 4 to 6 hours. The extended-release form is taken less frequently.
Why is Carbidopa-Levodopa Prescribed?
Levodopa on its own was the initial mainstay of Parkinson’s treatment starting in the 1960s. However, a major drawback was that only 1-5% of levodopa ingested actually reached the brain. The rest was metabolized and broken down in the bloodstream.
The addition of carbidopa overcame this obstacle. Carbidopa prevents the breakdown of levodopa before it can reach the brain. As a result, lower doses are required to achieve a therapeutic effect.
Carbidopa-levodopa provides the most dramatic improvement in Parkinson’s symptoms of any available therapy. It helps restore motor function and improve quality of life. It is usually the first line of treatment recommended to manage Parkinson’s disease symptoms.
What Happens When You Stop Taking Carbidopa-Levodopa?
Abruptly stopping carbidopa-levodopa can lead to problematic complications:
Rebound of Parkinson’s Disease Motor Symptoms
Without carbidopa-levodopa, dopamine levels in the brain plummet. This leads to a rapid worsening and rebound of Parkinson’s disease motor symptoms including:
- Increased slowness of movement (bradykinesia)
- Stiff, rigid muscles (rigidity)
- Shaking (tremors)
- Impaired balance and coordination
- Freezing during walking
Symptoms can deteriorate to a level equal or worse than the severity of Parkinson’s symptoms before initially starting carbidopa-levodopa treatment. The rapid decline in motor function from suddenly stopping medication can be disabling.
Neuroleptic Malignant Syndrome
Neuroleptic malignant syndrome (NMS) is a rare but potentially fatal reaction that can occur from abruptly stopping carbidopa-levodopa. It causes:
- High fever
- Severe muscle rigidity
- Mental status changes
- Rapid heart rate and blood pressure changes
- Abnormal blood work findings
NMS requires immediate emergency medical care to prevent organ damage, seizures, or death.
Dopamine Agonist Withdrawal Syndrome (DAWS)
Some Parkinson’s patients take dopamine agonists in addition to carbidopa-levodopa. Dopamine agonists mimic dopamine effects. Stopping them suddenly can trigger dopamine agonist withdrawal syndrome (DAWS).
DAWS can cause anxiety, panic attacks, depression, fatigue, sweating, and pain. Symptoms may begin within hours but can take up to 3 days to appear and typically improve over 2 weeks.
Other Complications
Abruptly stopping carbidopa-levodopa may also increase risks for:
- Falls and injuries from impaired mobility
- Aspiration pneumonia if swallowing problems occur
- Dehydration and malnutrition if eating problems develop
- Deep vein thrombosis and pulmonary embolism if immobility occurs
Patients who suddenly discontinue Parkinson’s medications are also at higher risk for suicide due to associated depression.
Why Stopping Carbidopa-Levodopa is Discouraged
Given the potential consequences, doctors strongly advise against Parkinson’s disease patients abruptly stopping carbidopa-levodopa without medical guidance. Reasons it is discouraged include:
- Deterioration of motor function and quality of life
- Higher caregiving needs
- Increased risk of falls and injuries
- Potentially life-threatening complications
- Worsening of non-motor Parkinson’s symptoms like depression
For most Parkinson’s patients, continuing carbidopa-levodopa and other prescribed Parkinson’s medications provides the best outcomes. The risks associated with sudden withdrawal typically far outweigh any potential benefits.
When Can Carbidopa-Levodopa Be Stopped?
In limited circumstances, discontinuing carbidopa-levodopa may be appropriate but this should always be supervised by a doctor. Reasons stopping treatment may be considered include:
Severe Medication Side Effects
If carbidopa-levodopa causes intolerable side effects, a doctor may recommend discontinuing its use. This requires tapering down the dose gradually under medical guidance to avoid withdrawal complications. Options include switching to other Parkinson’s medications.
Advanced Parkinson’s Disease
In very advanced Parkinson’s disease, medications may lose effectiveness over time. If disability progresses despite optimized treatment, discontinuing carbidopa-levodopa may be considered in select cases. Any tapering would need to be done incrementally with care.
End of Life Care
Discontinuing non-essential medications including carbidopa-levodopa may be appropriate for Parkinson’s patients undergoing hospice or end of life care. However, even in this setting, an incremental approach is advised.
How to Safely Stop Carbidopa-Levodopa
When deemed necessary, carbidopa-levodopa must always be stopped gradually and incrementally under medical supervision. Abruptly halting treatment puts patients at risk. Steps for safe withdrawal include:
- Consulting the prescribing neurologist
- Tapering the dose slowly over weeks to months
- Closely monitoring for worsening Parkinson’s symptoms
- Using additional supportive Parkinson’s medications as needed to manage symptoms
- Watching for psychiatric effects like depression and psychosis
- Adjusting the tapering schedule if symptoms spike
- Considering hospitalization for medically supervised withdrawal if needed
Following these steps and working closely with the care team can help mitigate risks from discontinuing carbidopa-levodopa.
Frequently Asked Questions
How quickly do Parkinson’s symptoms worsen after stopping carbidopa-levodopa?
Symptoms may start deteriorating within 12-48 hours but can worsen rapidly within days to weeks after completely stopping carbidopa-levodopa. The timeframe depends on how suddenly medication is withdrawn. Gradual tapering allows the brain to better adjust compared to abrupt cessation.
Can you just stop taking carbidopa-levodopa cold turkey?
It is extremely inadvisable to suddenly stop carbidopa-levodopa “cold turkey” without medical supervision. The consequences can be quite severe, including markedly worse Parkinson’s symptoms, increased fall risk, NMS, or even death in some cases. Tapering is necessary.
What happens if you run out of carbidopa-levodopa?
Try to never run out of Parkinson’s medications like carbidopa-levodopa due to the risks of suddenly stopping. But if you do run out, contact your doctor immediately to restart treatment. Temporarily use other Parkinson’s medications at higher doses. Seek emergency care if symptoms spike acutely or NMS is suspected.
Can you stop carbidopa-levodopa for surgery?
In most cases, it is recommended to continue taking carbidopa-levodopa before surgery. Stopping it may lead to problems with anesthesia, intubation, and post-op mobility. Talk to your doctor about adjusting the timing of doses around procedures. In rare cases where stopping for surgery is deemed necessary, tapering the dose pre-op and resume treatment ASAP after is key.
What if you miss a dose of carbidopa-levodopa?
If you occasionally miss a dose, just take your next scheduled dose on time. Do not double the dose. Try to avoid frequently missing or delaying doses which can increase motor fluctuations. If you regularly struggle taking carbidopa-levodopa on time, discuss options like extended-release formulations with your doctor.
Conclusion
Carbidopa-levodopa is the most effective oral medication for controlling Parkinson’s disease motor symptoms. But stopping it suddenly can lead to a rapid worsening of symptoms, medication withdrawal reactions, increased fall risk, and other medical complications. Doctors strongly advise against abruptly quitting carbidopa-levodopa without close supervision. When required, tapering down the dose slowly under medical guidance is crucial to safety manage withdrawal and avoid adverse outcomes. Ongoing treatment with carbidopa-levodopa provides the best results for most Parkinson’s disease patients.