drug administration and pharmacology of phenobarbital
DESCRIPTION
laboratory work for drug administration in pharmacology class. Diponegoro University, School of MedicineTRANSCRIPT
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Drug Administration
Laboratory of PharmacologyDepartment of Pharmacology and Therapeutics
Faculty of Medicine Diponegoro University2012
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• Enteral (oral? Intubation= nasogastric tube?)
• Parenteral (Injection= Intramuscular/Intravenous/Intraperitoneal/Subcutan)
• Inhalation• Topical
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Drug Administration
• oral• sublingual• Rectal/rectal suppository• application to other epithelial surfaces (e.g. skin, cornea, vagina
and nasal mucosa) topical-vaginal suppository• inhalation• Injection
– Subcutaneous– Intramuscular– Intravenous– Intrathecal– intravitreal.
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Enteral Administration
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Phenobarbital
• Barbiturate drug, trade name Luminal
• Mainly as Anticonvulsant• Hypnotic effect, Sedative effect,• Bioavailability after proper
administration = 95%• Metabolism= Hepatic
(Cytochrome P450)• Half-life= 53-118 hours• Excretion= Renal and Fecal
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Clinical Use
• Phenobarbital is useful in the treatment of partial seizures and generalized tonic-clonic seizures, although the drug is often tried for virtually every seizure type, especially when attacks are difficult to control
• Depresses neurons activities via Reticular Formation, Induces sleep (Sedative, Hypnotics, and Anesthetics)
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Formantio Reticularis
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GABA-mediated chloride ion channel
from Zorumski CF, Isenberg KE: Insights into the structure and function of GABA receptors: Ion channels and psychiatry. Am J Psychiatry 1991;148:162.)
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Pharmacokinetics
• The rates of oral absorption of sedative-hypnotics differ depending on a number of factors, including lipophilicity.
• Most of the barbiturates and other older sedative-hypnotics, as well as the newer hypnotics (eszopiclone, zaleplon, zolpidem), are absorbed rapidly into the blood following oral administration.
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Pharmacodynamics• Benzodiazepines and phenobarbital augment
the activation of the GABAA receptor by physiologically released amounts of GABA.• Elongates the GABA-mediated Chloride Ion
Channel Opening.• Elongates GABA and Glycine Inhibitory Effect • Chloride influx is increased, counteracting
depolarization. • Depresses the CNS via Reticular Formation.• Induces sleep (Sedative, Hypnotics, and
Anesthetics)