Levodopa: what is it for?

Levodopa is the basic therapy of Parkinson's disease. It is combined with other dopadescarboxylase inhibitor drugs, like cabidopa or benserazide, to treat this disease.

Levodopa is a medicine that belongs to the therapeutic family of antiparkinsonians. It is a drug that acts in the central nervous system, becoming dopamine in the brain.

The first person who associated Parkinson's disease with a dopamine deficit was the biochemist Oleh Hornykiewicz. He examined the autopsies of patients who suffered from Parkinson's disease and suggested this relationship. Later, this scientist began treating patients with a racemic mixture of DOPA, the results being positive.

Not long after, another scientist, Curt Porter, showed that the L-DOPA stereoisomer was really active, which reduced the effective dose of the compound in half.

Later, they began to synthesize different molecules, such as benzeraside or carbodopa, which improved treatment results. With this they also managed to reduce the dose necessary to achieve the desired effects.

Knowing some aspects of Parkinson's disease

Parkinson's is a disease of the central nervous system caused by a deficit of the neurotransmitter dopamine in striated neurons, due to the death of nigrostriatal neurons.

The origin of this disease is multifactorial. In addition, it has a fairly high prevalence in the general population. The most affected population group are the elderly. Specifically, it affects 2% of people over 65 years. However, it can also appear in young people.

Parkinson's presents a very common symptom that is the appearance of tremors. This symptom affects more than 60% of patients. However, other motor symptoms may also appear such as:

• Rigidity.
• Slow movements, also known as bradykinesia.
• Alterations in reflexes postural and falls.

Other symptoms that may appear with the course of the disease are:

• Dementia and memory loss.
• Hallucinations
• Depression.
• Dysphagia
• Muscle pain.
• Neuropathic pain.

Read also: Parkinson's disease

On the other hand, It is known that this disease is related to an increase in α-synuclein protein, which is also related to Alzheimer's. Therefore, the therapeutic strategy under investigation is to administer inhibitors of alpha-synuclein aggregation or immunization for these protein derivatives. There is a study conducted with Nilotinib that tries to investigate this type of therapy.

General characteristics of levodopa

Parkinson's therapy is about trying to increase dopamine levels acting directly on the receptors. This is done by inhibiting the degradation of the neurotransmitter or by inhibiting LAAD, which is the enzyme that transforms dopa into dopamine.

In this sense, it can be thought that why dopamine is not administered directly to the patient. The problem is that it has a high reuptake and metabolization, which prevents its absorption. Further, Dopamine is a very water-soluble molecule and, therefore, is unable to cross the blood brain barrier., which is what protects the brain

For all these reasons, Parkinson's is treated with the dopamine precursor, levodopa. This substance manages to cross the blood brain barrier and transforms into dopamine once it reaches the central and peripheral nervous system.

You may be interested: Blood-brain barrier

However, levodopa, although it crosses the blood-brain barrier very well, has a strong metabolism at the peripheral level, so The amount that reaches the brain is very small.

To solve this problem, It is given together with other drugs that inhibit the LAAD enzyme, as we have already commented. With this, it is possible to inhibit the transformation of levodopa to dopamine at the peripheral level and, ultimately, it is achieved that more levodopa reaches the brain.

Advantages of levodopa administration together with LAAD inhibitors

The co-administration of this type of medication reduces the amount of levodopa to be administered by 75%, since increase the half-life of the drug and help maintain levels more stable in the brain.

Therefore, its administration achieves greater clinical efficacy, which manifests itself in faster action. By reducing the amount of dopamine in peripheral tissues, decrease cardiovascular and gastrointestinal effects. Consequently, levodopa is always administered by combining it with benzeraside or carbidopa.

conclusion

Levodopa It is the first line of treatment to combat Parkinson's disease. It is given together with other drugs to increase its effectiveness.

You can ask your doctor or pharmacist any questions that you have about this disease and its treatment, as well as to inform you about the advances and clinical trials that are currently being carried out.