English Views: 1 Author: Site Editor Publish Time: 2022-10-03 Origin: Site
Levodopa is a prodrug of dopamine (DA), which itself has no pharmacological activity. It enters the center through the blood-brain barrier and is converted into DA by dopa decarboxylase to exert pharmacological effects.
1. Parkinson's disease (essential tremor paralysis)
Symptomatic Parkinsonism (non-drug-induced tremor paralysis syndrome) after 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 movements more normal. The effect is better for mild and moderate patients, and worse for severe or elderly patients.
2. Hepatic encephalopathy
It can make the patient wake up and improve the symptoms. Hepatic encephalopathy may be related to the abnormality of the central transmitter dopamine. After taking it, it can improve the central function and work. It is also believed that levodopa can improve the brain's tolerance to ammonia, but does not improve liver damage and liver function.
3. Neuralgia
Taken early to relieve neuralgia.
4. Hyperprolactinemia
It can inhibit the thyrotropin-releasing hormone in the hypothalamus and stimulate the prolactin-releasing inhibitor, thereby reducing the secretion of prolactin. It is used to treat hyperprolactinemia and has a certain effect on galactorrhea.
5. Hair loss
The mechanism may be to increase the concentration of catecholamines in the blood to tissues, which promotes hair growth.
6. Promote the growth and development of children
It can accelerate the growth and development of children's bones by promoting the secretion of growth hormone. Treatment of children with hypopituitarism.
1. Gastrointestinal reactions: At the therapeutic dose, approximately 80% of patients experience nausea and loss of appetite in the early stage. This is because DA directly stimulates the gastrointestinal tract and excites the emetic chemoreceptor area of the brain. Take it after meals, slowing down the rate of increase can be reduced. Or treat with domperidone (morphine).
2. Cardiovascular reactions: Mild orthostatic hypotension occurs in about 30% of patients in the early stage, which can be alleviated by continued medication. There are still arrhythmia and other reactions.
1. Taking amantadine, antan and this product together can enhance the efficacy of levodopa, but those with a history of mental illness do not advocate taking them together;
2. Antiacids, especially those containing calcium, magnesium or sodium bicarbonate, can increase the absorption of levodopa when used together with this product, especially in patients with slow gastric emptying;
3. Haloperidol blocks DA receptors in the brain and counteracts the efficacy of levodopa, which can cause extrapyramidal symptoms, which can aggravate the symptoms of Parkinson's disease;
4. It is forbidden to use with vitamin B6: the coenzyme of dopa decarboxylase can enhance the activity of peripheral decarboxylase, the side effects are aggravated, and the efficacy is reduced.
Since its introduction in 1967, levodopa has been the "gold standard" drug for Parkinson's disease. Although other therapeutic drugs have appeared in the field of Parkinson's disease in the past half century, the status of levodopa as the most basic drug has not been shaken.
Once diagnosed with Parkinson's disease, patients can be treated with levodopa as soon as possible, but the following points should be paid attention to when taking:
1. Start with a small dose and gradually increase the dose. Compound levodopa preparations include two dosage forms, dopashydrazine (also known as Madopa) and carbidopa (also known as Xinningmei). It is necessary to start with a small dose and gradually increase the dose to avoid acute adverse drug reactions, and strive to achieve the medication principle of "achieving satisfactory clinical effects with as small a dose as possible".
2. Levodopa should be taken 1 hour before or 1 to 2 hours after meals. Levodopa is absorbed in the small intestine, and ingestion of food can reduce the speed and extent of levodopa absorption. Moreover, the protein composition of food has a more obvious impact on the absorption of levodopa, so there should be no large amount of protein food in one meal, and the daily intake of protein should be evenly distributed among three meals.
3. Patients taking dopasehydrazine should avoid taking vitamin B6 at the same time, which will enhance the peripheral side effects of levodopa and reduce the efficacy. The effect of carbidopa is not interfered with by vitamin B6.
4. Patients with Parkinson's disease should take regular medication. Intermittent drug therapy or pulsed medication may accelerate the progression of Parkinson's disease. When taking larger doses of levodopa, remember not to stop the drug suddenly, so as not to induce malignant withdrawal syndrome.
