Methods of Drug Delivery Chapter 3 Methods of Drug Delivery

Delivery of Drugs Enteral – digestive tract Parenteral – major route; Given into the cardiovascular circulation Topical – by application onto the skin or associated membranes

Process of Drug Delivery Drug Administration Phase – depends on form of med, speed medication action is needed, desired location Enteral Parenteral Topical

Process of Drug Delivery Pharmacokinetic Phase – movement of drugs throughout the body to various targets Absorption Distribution Metabolism Excretion

Process of Drug Delivery Pharmacodynamic Phase – drugs produce a change or an effect at a specific target (receptor) Efficacy Potency

Physical Properties Influence how medications enter and move throughout the body

Physical Properties Solids – most effective via a body opening, need to dissolve first to become active, which slows the process

Physical Properties Liquids- move quicker through the body but need to penetrate the cellular membrane, viscosity can make it more difficult if it is higher, solubility the ability to dissolve will affect how easily it passes across the membrane

Physical Properties Hydrophobic- dissolve in lipids, work better penetrating body membranes

Physical Properties Hydrophilic – dissolve in water, work better in the bloodstream

Physical Properties Gas Fast absorption, moves quicker to target area and action is in seconds

Oral Route By mouth Can be chewed, swallowed, or dissolved in the mouth Tablets, capsules, powders, solutions, suspensions Dissolution delays the onset of action, water is needed or may be taken with food

Sublingual Absorbed quickly into the bloodstream Avoid the first- pass effect –intestinal absorption into the portal circulation to the liver to be metabolized by the liver

Rectal Use with unconscious patients, patients with N/V, infants not able to swallow pills Rapid onset of action due to blood supply

Injection Into the Blood Vessels IV Bolus Infusion Bypasses destructive enzymes of GI tract and the liver Fluid overload, infection

Injections Intradermal dermis easily absorbed Subcutaneous hypodermis Intramuscular muscles faster onset of action

Injections Advantage IM and subcutaneous Concentration of drug is predictable Confined to a precise location May be given to unconscious patients and children Disadvantage IM and subcutaneous Pain, swelling, tissue damage, infection

Injections Intrathecal directly in spinal subarachnoid space(dorsal spine spinal cavity beneath a sheath surrounding the spinal cord called the anrachnoid mater) spinal anesthetics or medications that might enter the cerebral spinal fluid

Injections Epidural directly into a space overlying the dura mater (most superficial layer of that protects the CNS)

Injections Intraperitoneal directly into the abdominal cavity

Injections Into the joint spaces (analgesics and anti- inflammatory drugs)

Topical Skin Eyes Ears Nasal membranes Reproductive openings Effect is systemic or local

Transmucosal Drugs Cross membrane lining Respiratory Reproductive tracts Effect: systemic or local Forms: suppositories, sprays, mists, foams, aerosols, volatile agents Examples: asthma, vaginal infections

Ears and Eyes Eyes Effect: to lubricate, prevent inflammation or treat infections of the cornea Forms: ointments, salves, or drops Ears Effect: to treat infections, cerumen buildup Forms: drops ( need to penetrate the ear canal and middle ear to be effective)

Client Teaching Oral: take with water or food to reduce nausea Establish a routine Follow dosing times, do not play catch up Store medication in a dry safe place Discard outdated medications Take medications with calibrated insert provided

End