Pharmacology And Body Systems Flashcards
What is pharmacology?
The study of drugs and their interactions with living organisms.
True or False: Pharmacodynamics is the study of how the body affects a drug.
False. Pharmacodynamics is the study of how drugs affect the body.
Fill in the blank: Pharmacokinetics is the study of how the body __________ drugs.
Pharmacokinetics is the study of how the body absorbs, distributes, metabolizes, and excretes drugs.
What is a drug receptor?
A protein molecule to which a drug binds to produce its effects.
What is a drug agonist?
A drug that activates a receptor to produce a biological response.
What is a drug antagonist?
A drug that blocks a receptor to prevent a biological response.
What is a side effect of a drug?
An unintended effect of a drug that is not related to its therapeutic action.
What is the placebo effect?
A beneficial effect produced by a placebo drug or treatment that cannot be attributed to its properties.
What is a therapeutic index?
The ratio of the dose of a drug that causes toxicity to the dose that produces a clinically desired or effective response.
True or False: Drug metabolism primarily occurs in the kidneys.
False. Drug metabolism primarily occurs in the liver.
What is the main route of drug excretion from the body?
The kidneys, through urine.
What is the blood-brain barrier?
A filtering mechanism in the blood vessels of the brain that prevents certain substances from entering the brain.
What is the role of the autonomic nervous system in pharmacology?
Regulating involuntary bodily functions and influencing the effects of drugs on the body.
What is the difference between sympathetic and parasympathetic nervous system responses?
Sympathetic responses prepare the body for fight or flight, while parasympathetic responses promote rest and digestion.
What is the primary neurotransmitter of the sympathetic nervous system?
Norepinephrine.
What is the primary neurotransmitter of the parasympathetic nervous system?
Acetylcholine.
How do sympathomimetic drugs affect the body?
They mimic the effects of the sympathetic nervous system, such as increasing heart rate and blood pressure.
What are common side effects of anticholinergic drugs?
Dry mouth, blurred vision, constipation, and urinary retention.
What is the main function of beta-blockers?
To block the effects of adrenaline on beta receptors in the heart, reducing heart rate and blood pressure.
What is the primary use of calcium channel blockers?
To relax and widen blood vessels, reducing blood pressure and increasing blood flow.
True or False: Diuretics are drugs that increase sodium and water reabsorption in the kidneys.
False. Diuretics are drugs that increase urine production by the kidneys.
What is the main mechanism of action of anticoagulant drugs?
To prevent blood clot formation by inhibiting the clotting process.
What is the primary function of bronchodilator drugs?
To relax and widen the airways in the lungs, making breathing easier.
What is the main purpose of analgesic drugs?
To relieve pain without causing loss of consciousness.
Coronary artery disease (CAD)
Definition
Arteries that supply the heart muscle become hardened and narrow.
Processes at play
Atherosclerosis - Lesions form in the arteries which cause narrowing and loss of elasticity.
Hypercholesterolaemia - High cholesterol in the blood (lesions in the arteries are made of cholesterol and lipids and collagen).
Hypertension - High blood pressure when the pressure in arteries is constantly high and puts strain on the system.
Heart failure
Definition
The heart (as a pump) is failing to meet the blood flow needs of the body.
Processes at play
Hypertension - With high blood pressure, the heart works harder to circulate blood; over time the heart muscle becomes thicker and eventually is too stiff to effectively pump blood.
Faulty heart valves - Valves ensure that the blood moves the correct way, if these do not work well the heart has to work harder.
Myocardial infarction - Over time, people with CAD may have an artery rupture, a blood clot forms and a section of the heart muscle becomes is damaged or may die.
Cardiac dysrhythmias
Definition
Abnormalities in the rhythm of the heart associated with an impairment of the conduction system.
Processes at play
Atrial fibrillation (AF) - Rapid and irregular heart rhythm caused when atria quiver rather than pump. The atrial contractions are not coordinated with ventricular contractions.
Ventricular fibrillation (VF) - When contractions of the ventricles are disorganised and the ventricles quiver rather than pump. Is the most serious dysrhythmia as there is no effective cardiac output and will be fatal if untreated.
Cardiac dysrhythmias
Definition
Abnormalities in the rhythm of the heart associated with an impairment of the conduction system.
Processes at play
Atrial fibrillation (AF) - Rapid and irregular heart rhythm caused when atria quiver rather than pump. The atrial contractions are not coordinated with ventricular contractions.
Ventricular fibrillation (VF) - When contractions of the ventricles are disorganised and the ventricles quiver rather than pump. Is the most serious dysrhythmia as there is no effective cardiac output and will be fatal if untreated.
Cardiomyopathy
Definition
Condition in which the cardiac muscle becomes inflamed, enlarged and weakened.
Processes at play
Often unknown - Contributing factors are genetic conditions, hypertension, tachycardia, cardiac arrhythmias, alcoholism.
Peripheral vascular disease (PVD)
Definition
Blood circulation disorder where vessels outside the heart narrow, block or spasm.
Processes at play
Atherosclerosis - Lesions form in the arteries which cause narrowing and loss of elasticity.
Hypercholesterolaemia - High cholesterol in the blood (lesions in the arteries are made of cholesterol and lipids and collagen).
Cerebral vascular accident (CVA or stroke)
Definition
Blood flow to a part of the brain is stopped.
Processes at play
Ischaemic stroke - Arteries in brain become narrow or blocked, causing severely reduced blood flow. Underlying cause can be related to atherosclerosis and/or hypercholesterolaemia.
Haemorrhagic stroke - Blood vessel in brain leaks or ruptures.
Severe hypoperfusion
Definition
A reduction in blood flow and the body tries to compensate by shutting down blood flow to the skin, visceral organs then heart and brain (peripheral to central shutdown)
Processes at play
Post cardiac arrest - Cardiac arrest occurs when the heart stops beating (e.g. as a result of ventricular fibrillation). If successfully treated, the heart may restart but the body may be in a state of hypoperfusion
Shock - A critical condition brought on by sudden drop in blood flow. May be secondary to blood loss (e.g. from trauma), severe infection (sepsis), anaphylaxis or other conditions (e.g. renal failure)
Congenital heart defects
Definition
A general term for a range of birth defects that affect normal heart structure and/or functioning. (Examples below).
Processes at play
Atrial septal defect (ASD) - A hole in the septum between the atria of the heart. Oxygen-rich blood leaks from the left atrium into the right atrium.
Ventricular septal defect (VSD) - A hole in the septum between the ventricles of the heart. Oxygen-rich blood from the left ventricle is forced through the defect into the right ventricle.
Tetralogy of Fallot - A combination of four congenital heart defects. The four defects are a VSD, pulmonary stenosis, a misplaced aorta and right ventricular hypertrophy. They usually result in a lack of oxygen-rich blood reaching the body.
Medications used for hypercholesterolaemia
Statins (Hypolipidaemic agents)
Medication examples: Generic (Trade) name
Atorvastatin (Lipitor)
Simvastatin (Lipex, Zocor)
Action
Act to lower cholesterol levels.
Does so by inhibiting a liver enzyme that is required to synthesis cholesterol and therefore lower the amount of circulating cholesterol in the blood (preventing formation of lesions).
Nursing responsibilities / Patient education
Patients should be advised to:
Take medication as a daily dose in the evening with food.
Have liver function tests every 4 to 6 weeks when dosage changed.
Contact doctor if experience:
very dark urine or yellowing of the eye sclera (as liver function may be affected)
muscle pain or muscle weakness (as inflammation of the muscles is a rare side effect).
Medications used for hypertension
Hypertension refers to elevated blood pressure. Antihypertensives act to lower blood pressure and do so by interfering with the normal body regulatory systems of the nervous, endocrine, cardiac and renal system. A great way to learn the major groups of the antihypertensive medication is using the acronym A, B, C, D, & E.
ACE inhibitors
ACE stands for Angiotension-converting enzyme
Medication examples: Generic name
Captopril
Enalapril
Perindopril
(Note: May end in “pril”)
Action
Act to lower blood pressure.
Do so by blocking the enzyme (angiotensin converting enzyme [ACE]) involved in the conversion of angiotensin I to angiotensin II. Allows blood vessels to relax and vasodilate.
Nursing responsibilities / Patient education
Monitor blood pressure before and after medication (as may drop blood pressure too low and cause dizziness).
Monitor potassium (K+) levels and renal function.
Angiotensin receptor antagonists
ACE stands for Angiotension-converting enzyme
Medication examples: Generic name
Irbesartan,
Candesartan
Losartan
Action
Act to lower blood pressure.
Do so as antagonises angiotensin II receptors so that smooth muscles in the vascular do not constrict.
Nursing responsibilities / Patient education
Monitor blood pressure before and after medication (as may drop blood pressure too low and cause dizziness).
Beta Blockers
Medication examples: Generic name
Atenolol
Carvedilol
Metoprolol
(Note: May end in “olol”)
Action
Act to lower blood pressure.
Are adrenergic antagonists and act by blocking the beta receptors on the heart muscle and reducing the effects of adrenaline, therefore heart beats slower and with less force.
Nursing responsibilities / Patient education
Monitor blood pressure before and after medication (may cause hypotension).
Monitor for other side effects (may cause cough, bradycardia, bronchospasm, sleep disturbances).
Calcium channel antagonists
Medication examples: Generic (Trade) name
Nifedipine (Adalat)
Verapamil (Isoptin)
Action
Act to lower blood pressure.
Do so by decreasing availability of calcium within the heart, this relaxes smooth muscle and reduces heart contractions.
Nursing responsibilities / Patient education
Monitor pulse and blood pressure before and after medication (as may cause bradycardia and hypotension).
Patients should be advised to avoid grapefruit juice when taking medication.
Diuretics
Types of diuretics
Thiazide diuretics e.g. Chlorothiazide (Dithiazide)
Loop diuretics e.g. Furosemide (Frusemide)
Potassium sparing diuretics: Spironolactone (Aldactone)
Thiazide diruetic - medication example:
Chlorothiazide
Act to lower blood pressure.
Do so by reducing blood volume; Inhibits the reabsorption of sodium, chloride and potassium ions, along with water, in the Loop of Henle.
Nursing responsibilities / Patient education
Monitor blood pressure before and after medication (may cause hypotension).
Monitor fluid balance and kidney function (may cause dehydration and kidney failure).
if taking a potassium depleting diuretic, patients should be advised to take potassium supplements as ordered.
Endothelin receptor antagonists
Medication examples: Generic name
Ambrisentan (Volibris)
Bosentan (Tracleer)
Action
Act to lower blood pressure.
Do so by blocking endothelin receptors and blocking constriction of smooth muscles.
Nursing responsibilities / Patient education
Monitor blood pressure before and after medication (may cause hypotension).
Medications used for cardiac tissue perfusion
Peripheral vasodilators
Medication examples: Generic name
Glyceryl trinitrate (GTN)
Isosorbide dintrate
Action
Acts to reduce workload on the heart by vasodilation of arteries and veins.
Can be prescribed for preventative (prophylactic) or therapeutic use.
Nursing responsibilities / Patient education
Monitor for excessive or cerebral vasodilation (may cause hypotension, headache, light headedness).
Medications to treat cardiac arrhythmias and severe hypoperfusion
Antiarrhythmics are a group of medications used to treat ectopic (extra) heart beats and stabilise excitable myocardial tissue (Bullock & Manias, 2022). There are a few different medications in this group, but digoxin is the most common and is used to treat atrial fibrillation, which is experienced by approximately 5% of Australian adults over the age of 55 years (AIHW, 2020). Digoxin is also used in paediatric patients. As some arrhythmias (notably ventricular fibrillation) can lead to cardiac arrest, we include in this section agents used in emergency situations to manage severe hypoperfusion (e.g. adrenergic agonists such as adrenaline and dobutamine)
Cardiac glycosides
Medication examples: Generic (Trade) name
Digoxin (Lanoxin)
Action
Cardiac inotrope: acts to increase the force of myocardial contraction and restore a normal, steady heart rhythm.
May be prescribed for atrial fibrillation, atrial flutter and cardiac failure.
Nursing responsibilities / Patient education
Can be administered orally or slowly, over at least 5 minutes, by an intravenous route.
Must monitor heart rate before administration. Withhold if < 60 beats/minute.
Has a narrow therapeutic index, so must monitor for toxicity e.g. nausea, vomiting, and blurred vision.
May interact with other medications (e.g. amiodarone)
In neonates and children, adhere to paediatric dosing guidelines and protocols.
Antiarrythmics: Calcium channel antagonists
Medication examples
Verapamil (Isoptin)
Action
Calcium channel antagonist which inhibits atrio-ventricular (A-V) conduction
Used for the treatment of dysrhythmias (such as extra ventricular beats)
Nursing responsibilities
Must monitor cardiac response (BP, HR, ECG) and urinary output.
Withhold if patient has hypotension.
Educate patient to avoid grapefruit and its juice as these can increase verapamil serum levels.
Antiarrythmics: Other
Adrenergic agonists
