From the FDA Drug Label
Sporadic cases of hyperpyrexia and confusion have been associated with dose reductions and withdrawal of carbidopa and levodopa tablets. Patients should be observed carefully if abrupt reduction or discontinuation of carbidopa and levodopa tablets is required, especially if the patient is receiving neuroleptics.
The effects of abruptly stopping carbidopa/levodopa therapy may include hyperpyrexia and confusion.
- Patients should be observed carefully if abrupt reduction or discontinuation is required.
- The label does not provide information on the effects of stopping levothyroxine therapy, as it is not mentioned in the provided drug labels 1 2. The FDA drug label does not answer the question regarding levothyroxine.
From the Research
It is not recommended to stop levothyroxine or carbidopa-levodopa abruptly, as this can lead to severe withdrawal symptoms and potentially life-threatening conditions, such as myxedema coma or neuroleptic malignant-like syndrome. For levothyroxine, which treats hypothyroidism, sudden discontinuation can lead to a return of hypothyroid symptoms including fatigue, weight gain, cold intolerance, constipation, and in severe cases, myxedema coma 3. For carbidopa-levodopa, which treats Parkinson's disease, abrupt cessation can cause a dangerous condition called neuroleptic malignant-like syndrome with symptoms including rigidity, high fever, confusion, and autonomic instability 4.
Key Considerations
- The body becomes dependent on these medications to maintain normal physiological function, and abrupt cessation can disrupt this balance.
- Gradual tapering of these medications is necessary to minimize withdrawal effects and prevent severe symptoms.
- If you need to stop either medication, work with your healthcare provider to develop a gradual tapering schedule.
- The tapering process allows your body to adjust slowly to decreasing medication levels, minimizing withdrawal effects.
Potential Risks
- Myxedema coma: a life-threatening condition that can occur if hypothyroidism is left untreated or if levothyroxine is stopped abruptly.
- Neuroleptic malignant-like syndrome: a rare but potentially life-threatening condition that can occur if carbidopa-levodopa is stopped abruptly.
- Withdrawal symptoms: such as fatigue, weight gain, cold intolerance, constipation, and dyskinesias.
Recommendations
- If you've accidentally missed doses, contact your healthcare provider immediately for guidance rather than restarting at full dose without medical advice.
- Work with your healthcare provider to develop a gradual tapering schedule if you need to stop either medication.
- Be aware of the potential risks and symptoms associated with stopping levothyroxine or carbidopa-levodopa abruptly, and seek medical attention if you experience any severe symptoms.