Pharmacology

• Right drug
• Right dose
• Right time
• Right route
• Right patient

Pharmocognosy = sources of drugs

Pharmacokinetics = absorption, distribution, metabolism and excretion of drugs in the body

Pharmacodynamics = using drugs to prevent/ treat disease

Toxicolgy = study of poisons and unwanted effects

Pharmacognosy = the source of drugs

• plant
• animal
• mineral
• chemical (synthetic)

• oral
• inhaler
• patch
• topical (applied to body surfaces; eyes, nose, vagina, skin...)
• intramuscular
• subcutaneous (beneath the skin)
• suppositry (rectum)
• intravenour (fastest route)

• route of administration
• ability of drug to dissolve
• food/fluids already in the body
• weight (body surface area)
• status of absorptive surface
• rate of blood flow to small intestine
• lipid solubility (ability to dissolve in fat)
• status of digestive system (old age/ poor system)

• transported by the blood stream
• water/fat soluable (dissolves in)
• areas of quick distrubution: liver, heart, kidneys, brain
• areas of slow distribution: muscle, fat, skin

• When the liver removes a drug before it is available for use (when orally administered)
• the liver may extensively metabolise a drug before it passes into the circulatory system (less effective?)
• IV administration bypasses the liver - preventing the first pass effect

Intravenous (IV) is the fastest route of administration

Danger of delayed drug metabolism:

• accumulation of drugs
• prolonged action of drugs

= possible overdose or adverse reaction when mixing drugs

Danger of stimulated drug metabolism:

• diminished pharmacologic effects (may not achieve desired effect/ too quick)

Through the:

• kindeys
• liver
• bowel

Enterohepatic circulation = circulation of drugs through the GI tract

Biliary excretion = initiated in the liver

• receptors are reactive sites on a cell which selectively bind with a drug creating a pharmacologic response

Affinity = how well a drug will fit with a receptor (better fit = better response)

Agonist = drug and receptor bind leadingto a pharmacologic response

Antagonist = prevent a substance binding to receptors (eg. Beta Blockers)

• effects depend on the cells or organ targeted by the drug
• once the drug hits the 'site of action' it can modify how and the rate at which a cell/ tissue functions

• Enzymes catalyse nearly all reactions in a cell
• drugs interact with enzymes to alter the response/effect
• can 'fool' enzyme into binding to a drug instead of a target cell

• doesn't involve a receptor site or an alteration in enzyme function
• main site of action is cell membrane
• drug will interfere or chemically alter cell function/ process
• final product - defect/cell death (eg. caner treatment/ antibiotics)

*sometimes not specific enough - e.g. could treat throat infection but cause an alteration in the bacteria of the vagina

• Theraputic effect = expected response
• Side effect = unintended secondary effects (from harmless to serious)
• Adverse effect = undesirable response
• Toxic effect = developed after prolonged intake /impaired metabolism or excretion
• Idiosyncratic reaction = unpredictable effects (differs per individual)
• Allergic reaction = drug acts as antigen (bad) which triggers the body to release antibodies - can be mild-severe (eg. hives/itching)

Pregnancy

• drugs can cross the placenta
• first trimester is the period of greatest danger for drug induced fetal defects
• can affect growth and functional developments in second trimester
• can affect labour/the neonnate

Breast Feeding

• exposes bf infants to drugs consumed by mother
• risk to benefit ratio must be considered