Pharmacology for the Nurse Educator
Pharmacokinetics
Involves ADME (absorption, distribution, metabolism and elimination).
Absorption: absorption from the administration site either directly or indirectly into the
blood/plasma.
Distribution: reversibly or irreversibly move from the bloodstream into the interstitial and
intracellular fluid.
Metabolism: bio-transformed via hepatic metabolism or by other tissues.
Elimination: lastly, the drug & its metabolites are eliminated from the body
The route of administration with the highest bio-availability is
Intravenous; putting entire dose into a patient's vein and bypassing absorption. Intravenous
route avoids first-pass metabolism in the liver.
rectal administration disadvantages
variable and erratic absorption
Steady state (SS)
is usually reached within 4-5 half-lives of a drug
The half-life of a drug is defined as
how long it takes for half the drug to be excreted from the body
Half-life of a drug
Determines how frequently the drug must be administered
Predicts how long toxic effects can last
Half-life is constant with first-order pharmacokinetics of a drug
,Zero-order (nonlinear) pharmacokinetics means a drug is metabolized at a constant rate per
unit time.
CYP3A4 substrate drugs
May have enhanced activity if any CYP3A4 inducer drugs are used along with it.
Drug development steps (according to the FDA)
Discovery: laboratory research to develop the new drug
Pre-clinical research with animal testing for safety (Phase I)
Clinical research on human subjects for medication safety (Phase II)
Clinical research in humans comparing the new drug to accepted medications or placebo
depending on the study (Phase III)
FDA review of the results to determine approval
Post-marketing study to identify adverse effects not found in earlier clinical studies (Phase IV)
Medication safety organizations
The Institute for Safe Medication Practices (ISMP)
The Institute of Medicine (IOM)
The Joint Commission
The National Coordinating Council for Medication Error Reporting and Prevention (NCCMERP)
Food and Drug Administration (FDA) Safe Use Initiative
Adverse Drug Reactions (ADRs)
Two basic type of ADRs: pharmacological and idiosyncratic.
85% to 90% of ADRs are pharmacological.
Adverse drug reactions are usually preventable, frequently occur in a hospital or nursing home
setting, and include medication errors, adverse drug effects, allergic and idiosyncratic type
, reactions.
ADRs are not commonly reported; the FDA does not mandate that ADRs be reported.
Polypharmacy involves using multiple healthcare providers for care, using multiple medications,
and using several pharmacies for prescription filling.
Cardiovascular-Angiotensin converting enzyme inhibitors (ACEIs):
Lisinopril, captopril, enalapril, ramipril, benazepril, fosinopril;
*ACEIs reduce blood pressure by suppressing the release of angiotensin-converting enzyme.
*Important side effects of ACE inhibitors include cough and angioedema; discontinue the ACEI if
angioedema occurs.
Angiotensin II receptor blocking agents (ARBs):
Candesartan (Atacand), eprosartan (Teveten), irbesartan (Avapro), losartan (Cozaar), telmisartan
(Micardis) and valsartan (Diovan).
ARBs reduce blood pressure by blocking angiotensin II receptors.
Cardiovascular-Essential (primary) hypertension
Accounts for 90% of cases; secondary hypertension may be caused by chronic renal failure.
Nitroglycerin
nitrate drug used in the treatment of angina; a nitrate drug that can be administered IV, SL, a
topical ointment and as a transdermal patch
PDE-5 inhibitors
-Pulmonary hypertension therapy
-Include sildenafil. Inhibit cGMP PDE5 and prolong vasodilatory effect of nitric oxide.
cGMP phosphodiesterase
an enzyme in cells that converts cGMP into GMP
Amiodarone
is the antiarrhythmic of choice when there is coexisting heart failure; can cause thyroid and
pulmonary toxicity.
Alpha-1 adrenergic stimulation
results in vasoconstriction and increased blood pressure.