AnestheticsLecture - 1

Md. Amran HowladerLecturer

Dept. of Pharmacy, SEU

What is drug?

• A chemical substance of known structure, other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect.

Drug Vs Medicine

• Drugs may be synthetic chemicals, chemicals obtained from plants or animals, or products of genetic engineering.

• A medicine is a chemical preparation, which usually but not necessarily contains one or more drugs, administered with the intention of producing a therapeutic effect

Drug Vs Medicine- contn’d

• Medicines usually contain other substances (excipients, stabilisers, solvents, etc.) besides the active drug, to make them more convenient to use.

• To count as a drug, the substance must be administered as such, rather than released by physiological mechanisms.

General anesthetics

• General anesthetics are structurally diverse class of Drugs that produce a common end point- a behavioral state referred to as general anesthesia.

• General anesthesia can be defined as a global but reversible depression of central nervous system function resulting in loss of response to and perception of all external stimuli.

• The state of general anesthesia usually includes analgesia, amnesia, loss of consciousness, inhibition of sensory and autonomic reflexes and in many case skeletal muscle relaxation.

Crietria of an ideal anesthetics

• Anesthetics should induce anesthesia smoothly and rapidly and permit rapid recovery as soon as administration ceased.

• The drug should have a wide range of safety and be avoided of adverse effects.

Signs and stages of analgesia

The solubility properties of anesthetics

Arterial concentration in the inspired blood

Pulmonary Ventilation

Pulmonary Blood flowDrugs with moderate to high solubility in

blood

Pulmonary Blood flowDrugs with low solubility in blood

Arteiovenous concentration gradient

?????• Lippincott’s Illustrated Reviews- Harvey, Champe• Clinical Pharmacy and Therapeutics- Walker• Pharmacology- Rang, Dale, Flower & Ritter.• Pharmacology- Goodman n Gillman• End of Lecturer