Pharmacodynamics and pharmacokinetics of ergot alkaloids

Ergodine is metabolized and excreted quickly, and its maintenance time is short. The oral absorption of ergotamine and ergotoxine is slow and irregular. The dose of oral ergotamine is 8 ~ 10 times higher than that of intramuscular injection, and the onset time is about 20min minutes, but the duration of action is longer. The drug is ergot alkaloid, which was used as vasodilator in peripheral vascular diseases in the early stage. 198 1 was officially rated as a drug to improve the metabolism of brain cells by the US FDA. Its functions are as follows:

(1) Improve the metabolism of neurons: The drug can inhibit the activities of ATPase and adenylate cyclase, reduce the decomposition of ATP, improve the energy balance of brain cells, and transform anaerobic fermentation of glucose into aerobic oxidation, thus improving the utilization rate of glucose, increasing the energy of neurons and improving the potential activity and microcirculation.

(2) Drugs can directly act on dopamine and serotonin receptors in the central nervous system, enhance the stimulation of neurotransmitters released by presynaptic nerve endings and postsynaptic receptors, and improve the nerve transmission function.

(3) The drug can block a receptor, relieve vasospasm and reduce vascular resistance, thus increasing the blood supply and oxygen utilization rate of brain tissue.

(4) This medicine can accelerate the frequency and increase the amplitude of a wave in EEG, thus improving the EEG abnormality of the elderly. The drug was absorbed rapidly by oral administration, and its blood concentration reached its peak at about 65438 0.5 hours. Due to the first-pass metabolism of the liver, 25%-50% of drugs enter the blood circulation. The plasma clearance half-life is about 4 hours. Active substances are rapidly excreted through metabolism.