Introduction

Levodopa is a precursor drug of dopamine (DA), which has no pharmacological activity. It enters the center through the blood-brain barrier and is transformed into DA by dopa decarboxylase. Levodopa primary tremor paralysis and non drug induced tremor paralysis syndrome[1]. The appearance of levodopa is characterized by white or off white crystalline powder. The alias of levodopa is (s) - 2-amino-3 - (4-hydroxyphenyl) propionic acid. The density of levodopa is 1.47 g / cm ³。 The melting point of levodopa is 276 to 278 ℃. Levodopa has certain water solubility. C9H11NO4 of levodopa.

Picture 1 Levodopa Powders

The role of levodopa in medical treatment

Levodopa can improve myotonia and bradykinesia. Continuous medication is also effective for tremor, salivation, postural instability and dysphagia[2].

1. Symptomatic Parkinson's syndrome (non drug-induced tremor paralysis syndrome) after Parkinson's disease (primary tremor paralysis) encephalitis or combined with cerebral arteriosclerosis and carbon monoxide and manganese poisoning of the central nervous system. It can reduce the symptoms of tremor paralysis, improve muscle tension and make limb activities more normal. The effect is better for patients with mild and moderate disease, and worse for patients with severe or elderly disease.

2. Hepatic encephalopathy. Levodopa can make patients awake and improve symptoms. Hepatic encephalopathy may be related to the abnormality of central transmitter dopamine. After taking it, it can improve central function. Others believe that levodopa can improve brain tolerance to ammonia, but can not improve liver injury and liver function.

3. Neuralgia. Early administration of levodopa can relieve neuralgia.

4. Hyperprolactinemia. Levodopa can inhibit thyrotropin releasing hormone in hypothalamus and excite prolactin releasing inhibitory factor, so as to reduce prolactin secretion. It is used to treat hyperprolactinemia and has a certain curative effect on galactorrhea.

5. Depilation. The mechanism may be that levodopa increases the catecholamine concentration from blood to tissue and promotes hair growth.

6. Promote the growth and development of children. Levodopa can accelerate the growth and development of children's bones by promoting the secretion of growth hormone. Treat children with hypophysis.

The role of levodopa in medical treatment

There are many adverse reactions, which are difficult to avoid due to the long time of medication. It is mainly caused by excessive peripheral dopamine. Properly adjusting the dose can reduce the adverse reactions.

1. Gastrointestinal reactions: nausea, vomiting and loss of appetite, which can be seen in the early stage of treatment and occur in about 80% of patients. After 3 months of medication, there may be restlessness, insomnia, hallucinations and mental symptoms. In addition, there may be postural hypotension, arrhythmia and involuntary movement. Pay attention to adjust the dose and stop the drug if necessary.

2. "On-off" phenomenon (patients with sudden hyperactivity and restlessness are "on", and then myotonic movement can not be "off"), which is seen in younger patients and occurs in some patients more than one year after medication. This phenomenon can be controlled by reducing the dose or intravenous levodopa.

3. Intraday fluctuation may be due to the narrow threshold of dopamine sensitivity of striatal dopamine receptor to dopamine. When the concentration of dopamine reaches the peak after taking this product, there is dyskinesia; When the concentration of dopamine decreases, it reverses to the inactive state, resulting in significant fluctuations of motor symptoms within one day. Proper adjustment of taking time and method and taking small doses several times can reduce the fluctuation within the day.

4. Dysuria is more likely to occur in the elderly.

Cautious

1. Hypertension, arrhythmia, diabetes, bronchial asthma, emphysema, liver and kidney dysfunction, urinary retention are used cautiously.

2. The elderly with osteoporosis, who are effectively treated with this product, should slowly return to normal life to reduce the risk of fracture.

3. Pay attention to blood routine examination, liver and kidney function and ECG during medication.

4. This product can be secreted into milk and reduce milk secretion.

Animal experiments show that this product can cause visceral and bone deformities. FDA rated the pregnancy safety of this drug as grade C.

5. Use with caution for children.

Reference

1 Wu weizhe, Zhou yanchuang, et al Comparison of levodopa content in cat beans at different harvest periods. Shizhen national medicine, 2009

2 Cai dingfang, Chen Xiqun, Gao Ying, Liu Jing, etc Effect of Bushen Yanggan Recipe on the function of substantia nigra and striatum in Parkinson's rats after long-term administration of levodopa. Chinese Journal of integrated traditional Chinese and Western medicine, 2001