Levaodopa, also called L-Dopa is the existing gold standard for the treatment of Parkinson’s disease. For over 30 years, this has been the trusted drug of choice, even though there are newer medications available now.
What is Parkinson’s disease?
Parkinson’s disease is a slowly progressive neurological condition occurring due to the lack of dopamine in the brain cells. Dopamine is one of the neurotransmitters involved in the transmission of information through the nerves. Movement, muscle control and balance are commonly affected if there is a deficiency of dopamine; hence the symptoms of Parkinson’s disease are related to these.
What are the signs and symptoms of Parkinson’s disease?
The most common signs are
1. Tremor- uncontrolled shaking of the body while atnrest. This is especially noted at the hands.
2. Bradykinesia- Slowness & difficulty beginning a voluntary movement. Simple movements like standing up from a sitting position, turning to one side etc may become difficult, as the disease progresses.
3. Muscle stiffness
4. Imbalance. The patient frequently loses balance and there is a high risk of falls. In elderly people, the bones are extremely fragile, hence any fall might add to the complications already present.
The symptoms presented are
1. Hypomimia- a lack of expression on the face. This occurs due to the damage of the nerves controlling the facial movements.
2. Hypophonia- the voice becomes softened. Other people may find it difficult to hear when the person with Parkinson’s disease is speaking.
3. Microgrpahia- handwriting becomes smaller.
4. Depression.
5. Constipation.
Management of Parkinson’s disease
The treatment of Parkinson’s disease is aimed at improvement of the daily living of the patient. No definitive treatment modality has been developed till now. It is better to start the treatment for the disease at the earliest, once the diagnosis is made, as there might be adverse effects in the later stages of the disease, if treatment is not given.
Medications used in the treatment of Parkinson’s disease
Levodopa is the most commonly used medication for managing Parkinson’s disease. This is used in combination with other medications, thereby improving the condition of the patient.
Mechanism of action of Levodopa
Levodopa is a naturally present substance in animals and plants. But taken orally the dopamine from these products might not reach the brain. This is being done by the medication. Levodopa, taken in the form of medication, reaches the brain cells where it is converted into dopamine. The dopamine producing brain cells, take in the dopamine and the symptoms of Parkinson’s disease is reduced.
Levodopa used in combination treatment
Levodopa alone is not commonly used for the treatment of Parkinson’s disease. it is always used in conjunction with other medications like carbidopa or benserazide. The combination therapy is more effective because carbidopa or benserazide if used along with levodopa would restrict the conversion of levodopa into dopamine outside the brain. This results in the optimal amount of dopamine in the brain.
Levodopa is most effective against rigidity and slowness present in the Parkinson’s disease. It is not as effective against the imbalance or tremor.
Side effects of Levodopa
1. Nausea and vomiting- in the initial stages of the treatment. As doses are increased, the dose of carbidopa or benserazide is adequate in controlling this side effect.
2. Dyskinesias- involuntary movements like jerking, writhing, nodding might occur.
3. Low blood pressure- in the initial stages if the dosage is higher than required.
4. Arrythmia
5. Hairloss
6. Confusion
7. Visual and auditory hallucinations.
8. Wearing off effect- if the dose of levodopa is not adequate to control the symptoms, or if adequate levodopa has not reached the brain, the symptoms might be evident before it is time for the second dose. This is called wearing off effect and most people think it is a worsening of the disease because of the medication. The progression of the disease might be a reason for this effect.
For each patient, the disease manifests in a different way. The treatment of the disease and the dosage of the drugs are also individual.
There are other newer drugs also included in the treatment of Parkinson’s disease, used in combination with levodopa.