Drug Administration Rights and Methods

Study Notes

Concentration of drug in the body that produces the desired effect is important, along with minimal or no signs of toxicity or lack of effect.
Patient identity must be verified.
Administering a drug at the correct time maintains desired therapeutic effect and avoids toxicity.
Verify the correct drug four times: removal from storage, dispensing, when returning to the pharmacy, and before giving to the patient.
Right drug strength is important.
Right documentation is crucial, including legal and safety obligations requiring the owner's consent to treatment.
The correct route and technique, patient weight, and dosage must also be correct.

The mass of drug required per unit of body weight (e.g., 2 mg/kg).
Calculated mass of drug administered at one time (e.g., dose = drug dosage x body weight).

High margin of safety means the lethal dose is much higher than the effective dose. Drug has a high therapeutic index.
Low margin of safety means the lethal dose is close to the effective dose. Drug has a low therapeutic index.

Excludes the small intestine (enteral routes).
IV Injection: Fastest way to achieve drug effects with immediate response and 100% bioavailability.
Know the concentration of drug in the blood

Inhalant: Rapid absorption due to a large surface area, drug turns into a gas, nebulised -- Drug turns into a fine spray/ mist. (lung-> alveoli -> blood capillaries)
Topical

Skin, eyes, ears: Dissolution, penetration, diffusion, localized treatment.
Oral Administration: Slower onset than parenteral routes, does not need to be sterile. Requires 3 events: Dissolution, Liberation, Passage through GI tract and vasculature.

Absorption: Movement from administration site into the blood (vascular system). Affected by: Patient characteristics and dose form.
Distribution: Movement to tissues. Affected by Body construction, function, route (eg;Solubility, Ionization, molecule size, pKa of Drug), pH of environment Drug is in, vascular system.
Metabolism: Chemical alterations, primarily in the liver. Affected by various factors including, liver , kidneys, small intestine, etc.
Excretion: Elimination from body. Primarily through urine or bile; consideration for milk in lactating animals. Affected by Various pathways (kidney, liver, lungs, saliva, intestine, sweat).

Effect of drug on the body including depression, stimulation, destruction, irritation, and replacement.
Mechanisms for Drug Movement:
Passive Diffusion: Movement from high to low concentration; requires no energy.
Facilitated Diffusion: Requires carrier proteins, no energy.
Active Transport: Requires energy, moves against the concentration gradient.
Pinocytosis and Phagocytosis: "Cell drinking" and "cell eating"