Drug Administration

Laboratory of PharmacologyDepartment of Pharmacology and Therapeutics

Faculty of Medicine Diponegoro University2012

• Enteral (oral? Intubation= nasogastric tube?)

• Parenteral (Injection= Intramuscular/Intravenous/Intraperitoneal/Subcutan)

• Inhalation• Topical

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.

Enteral Administration

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

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)

Formantio Reticularis

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.)

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.

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)