PTCB - Medications Pt. 1

What are the two major branches of pharmacology?

Pharmacodynamics and pharmacokinetics

Pharmacodynamics

what the drug does to the body; studies the biochemical and physiological effects of drugs on the body

Pharmacokinetics

what the body does to the drug

What are the four components of PK?

Absorption, distribution, metabolism, excretion (ADME)

Absorption

the process of drugs entering the body and getting absorbed by the small intestine and into the bloodstream

Distribution

the process of the drug being distributed and dispensed throughout the body by the bloodstream

Metabolism

also known as Biotransformation; the body chemically alters the drug through the liver or GI tract

Excretion

the drug and its metabolites are eliminated from the body through the kidneys and bladder

Bioavailability

the amount of administered drug that reaches blood circulation and can be used by the body (depends on the route of administration)

A drug that is administered intravenously has a bioavailability of ___%

100

When two drugs have the same bioavailability, they are known to be __________

Bioequivalent (BE)

Bioequivalent

drugs that are absorbed equally into the body and have the same bioavailability

Orange Book

an FDA publication of approved drugs products and their therapeutic equivalence

Oral (PO)

by mouth

Sublingual (SL)

under the tongue

Buccal (BUCC)

between the gums and cheek

Intramuscular (IM)

into the muscle

Subcutaneous (SC)

under the skin

Intravenous (IV)

into the vein

Intrathecal (IT)

into the spinal cord spaces

Rectal (PR)

into the rectum

Vaginal (PV)

into the vagina

Transdermal (TD)

through the skin

Intranasal (IN)

into the nostril

Topical (TOP)

onto the skin

Inhalation (INH)

into the lungs

Otic (AS, AD, AU)

into the ear

Ocular or ophthalmic (OS, OD, OU)

into the eye

Pharmacodynamics is important because…

it helps us learn what the optimum dose of a drug should be

Optimum dose

limits side effects while maximizing the clinical effect of the drug

Receptors

proteins located inside cells or on the cell surface that interact with administered drugs to produce an effect in the body

Agonist drug molecules

mimic normal physiological processes in the body, and they bind to a receptor to activate it an generate a response (they often. mimic neurotransmitters)

Antagonist drug molecule

designed to block or inhibit an agonist from activating a receptor

Dopamine

a neurotransmitter involved in motivation and reward and regulates mood, attention, and learning

Low dopamine results in…

Parkinson’s disease

High dopamine results in…

schizophrenia

Epinephrine (Adrenaline)

a neurotransmitter that initiates the “fight” flight” response and affects alertness and arousal

Histamine

a neurotransmitter involved in immune response, inflammation, and gastric acid secretion; it affects wakefulness, appetite, and cognition

Serotonin (5-HT)

a neurotransmitter that contributes to sleep, mood regulation, appetite, and digestion; low levels are associated with depression and anxiety

Therapeutic index (TI)

indicates the range of doses at which a medication is both safe and effective

Narrow therapeutic index (NTI)

drugs with a NTI have a very small gap between their effective doses and those that produce adverse effects

Therapeutic drug monitoring is done by…

measuring “trough and peak” in the patient’s blood

Trough

the lowest blood concentration of a drug

Peak

the highest blood concentration of a drug

Cyclosporine

immunosuppressant used in organ transplant

Digoxin

atrial fibrillation drug

Digitoxin

anti arrhythmic drug

Fosphenytoin

anti epileptic drug

Levothyroxine

hypothyroidism drug

Lithium

bipolar disorder drug

Phenytoin

anti epileptic drug

Theophylline

asthma and COPD (chronic obstructive pulmonary disease) drug

Warfarin

blood thinner (anticoagulant)

Drug-drug interactions

occur when two or more drugs interact with each other

Addition (drug-drug)

the combined effect of two drugs is the same as the effects of each drug taken alone (one drug adds on to the effects of another)

Antagonism (drug-drug)

the action of one drug blocks or works against the action of another drug

Potentiation (drug-drug)

one drug enhances or prolongs the effects of another drug

Synergism

the combined of effect of two drugs is greater than the sum of the effect of them individually

Selective Serotonin reuptake inhibitors (SSRI’s) are used to treat _________, and triptans are indicated to treat _________

depression; migraines

Naloxone blocks the effects of ________

morphine

Nitrates (nitroglycerin) and phosphodiesterase-5 (sildenafil) both cause ________ _____ ____

increased blood flow (vasodilation)

Co-administration of nitroglycerin and sildenafil can cause ______ _______, leading to ______ _________

extreme vasodilation: severe hypotension

Drug-disease interactions

occurs when certain diseases/conditions alter the absorption or elimination of some medications, so the drug may cause harmful effects because of an underlying disease/condition

Pseudoepinephrine is the active ingredient in some OTC nasal decongestants due to its ___________ effect

vasoconstrictive

Laxatives can cause ________ and _______ _________

dehydration; electrolyte imbalance

Drug-nutrient interactions

occur when certain foods or drinks increase or decrease the effects of drugs in the body

Grapefruit juice is contraindicated from…

statins

Green leafy vegetables are contraindicated from…

warfarin

Medications that interact with certain minerals such as calcium should be separated from dairy or mineral-containing products for at least…

two to four hours

Some examples of drugs that interact with calcium and other minerals include…

biphosphonates (alendronate), fluoroquinolone antibiotics (ciprofloxacin, levofloxacin), levothyroxine

Drug-herbal interactions

occur when herbal or dietary supplements increase or decrease a drug’s effects

______ ______, a herbal supplement, increases the risk of bleeding

__ ________ ____, a herbal supplement used to treat depression, increases the adverse effects of antidepressants

St. John’s Wort

St. John’s Wort can also decrease the effectiveness of ___ _________ ___________

HIV antiviral medications

Drug-alcohol interactions

occur due to alcohol’s chemical reactions with the drug itself or because alcohol can have additive harmful side effects with some CNS depressants

___________ (Flagyl), is an antibiotic that is contraindicated with alcohol because of a “disulfiram-like” reaction that causes vomiting and stomach pain

Metronidazole

Opioid analgesics (oxycodone, tramadol) are contraindicated with alcohol because…

the have the risk of additive CNS depression

Drug-labratory interactions

occur when medications interfere with laboratory testing and cause incorrect results

Thiazide diuretics and loop diuretics can…

elevate HDL cholesterol levels

Barbiturates, thiazide diuretics, corticosteroids, and oral contraceptives can…

elevate blood glucose levels

Beta-blockers, aspirin, and trimethoprim/sulfamethoxazole can…

decrease blood sugar

Thiazide diuretics, angiotensin-converting enzyme (ACE) inhibitors, NSAID’s, and caffeine can…

cause hypokalemia

Hypokalemia

low serum potassium