ผู้วิจัย/Authors: Vicharn Vichaiya

ชื่อเรื่อง/Title: Clinical Pharmacology of Levodopa

แหล่งที่มา/Source: Journal of The Psychiatric Association of Thailand, Vol. 17, No 1, January 1972, Page 25-43.

รายละเอียด / Details:

The first trial of levodopa in Parkin son's disease was performed in 1961, following a demonstration of striatal dificiency in parkinsonian patients under autopsy. The rationale can be summarized as follows: (1) depletion of dopamine is fresumably due to degeneration of fibers of the nigrostriatel tract, (2) dopamine may act as specific transmitter at certain synapses, (3) dopamine cannot cross the blocd-brain barrier, but its immediate precursor, levodopa, does so readily and restores function by replenishing dopamine. Levodopa is rapidly absorbed from gastrointestinal tract, with peak levels occuring in plasma one-half to two hours. Lovodopa metabolites appear rapidly in plasma mostly in the from of phenylcar-boxylic aeids. Radioactive compounds are rapidly excreted in urine. In replacement therapy high doses of prolonged period is necessary. In reported trials of 2}000 to 3}000 patients, the ratio of suecesful response to failure has been approximatily 3.5 to 1. Rigidity and hypokinesia are of good and early response. Tromer response is irregular and may occur only agter prolonged dosage. The usual initial dosage of levodopa is 300 to 500 mg. With gradual increase. The optimal daily desage ranged from 2.5 to 6.0 gm. Only less than 5% of patients have to stop medication due to untolerable toxicity. The reported side-effects involve any system, but common symptoms are only (1) nausea, vomiting, and anorexia, (2) cardiac dysrhythmias, (3) hypotension (4) abnormal involuntary movements, and (5) behavioral and personality changes. Confirmed clinical episodes of drug interactions are relativety few. However, care chould be excereised when combining other drugs with levodopa.

Keywords: pharmacology, levodopa, parkinson's disease

ปีที่เผยแพร่/Year: 1972

Address: Somdet Chaopraya Hospital, Bangkok 6.

Code: 0000555

ISSN/ISBN: -

Country of publication: Thailand.

Language: English.

Category: Case Report: Journal.

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