Pharmacology Flashcards
Drugs interact with specific molecules in the body, such as receptors, enzymes, ion channels, and transporters. True/false?
True
What are the 2 main drugs types?
Agonists and antagonists
Interactions can either enhance (agonist) or inhibit (antagonist) the activity of the target molecule.
What is pharmacodynamics?
Pharmacodynamics is the drug’s biological effect and mechanism of action
.
What is pharmacokinetics?
Pharmacokinetics is body’s response to drugs.
What is drug affinity?
drug affinity applies to both agonists and antagonists, and is the binding/unbinding to cells.
What is drug efficacy?
Drug efficacy doesn’t apply to antagonists
Is the measure of drug activation and action
What is orthosteric vs allosteric binding?
Orthosteric, which bind at the active site; and allosteric, which bind elsewhere on the protein surface, and allosterically change the conformation of the protein binding site.
What are the 4 receptor types and their mechanisms of actions?
LGIC (ligand-gated ion channel) is induced by electrolyte transport.
GPCR (G-protein coupled receptors) is secondary mechanism with use of alpha and beta-gamma complex and ATP.
Kinase-linked receptors operate by binding of stimulus leading to phosphorylation or other mechanism on receptors, resulting in release of substitute proteins and causing effect.
Nuclear receptors act by hormone diffusing into the cell and nucleus, resulting in hormone response and transcription of genes (on and off)
What are the 4 factors that influence drug absorption?
solubility of the drug, chemical stability, lipid to water coefficient, degree of ionisation
What are the 9 different routes of drug administration?
PO (orally)
IM (intramuscular)
IV (intravenous)
Subcutaneous
Transdermal
Eye drop
Per rectum
Inhalation
Sublingual
Describe drug metabolism and the main site of action?
drug metabolism occurs by two steps.
Step 1 is oxidation, reduction and hydrolysis.
Step 2 is conjugation. Both occur in the liver
Describe the process of drug excretion and the main site of action?
Drug excretion occurs in the kidneys by glomerular filtration, active tubular secretion and passive reabsorption by diffusion.
What is elimination rate constant (Ke), and its relationship with changes in dosage?
elimination rate constant (Ke) is fraction of drug elimated per unit time.
Increased dosage doesn’t affect half life or Ke of the drug
What is clearance (CL) of a drug?
Volume of plasma cleared of drug in unit time
What are the effects of noradrenaline and epinephrine (sympathetic), noting the receptor action, effects on HR/contractility/conduction veolicity/duration of systole?
Noradrenaline and epinephrine both act on beta1 adrenoceptors.
This increases HR, contractility, conduction velocity and reduces duration of systole.
What is acetylcholine and it’s receptor? What effects does it have on HR, contractility and systole?
ACh is a postganglionic parasympathetic neurotransmitter that acts on muscarinic M2 receptors. This reduces HR, contractility and increases duration of systole
What are examples of beta blockers?
Selective BBs include Bisoprolol, Atenolol.
Non-selective BBs include propranolol.
Non-selective vs selective beta blockers target receptors?
Selective beta blockers primarily block the beta-1 adrenergic receptors.
Non-selective beta blockers block both beta-1 and beta-2 adrenergic receptors.
What are adverse effects of beta blockers?
Adverse effects of beta blockers include bradycardia, cold peripheries and bronchospasms
Indications for selective beta blockers?
They are commonly used to treat conditions such as hypertension, angina (chest pain), and certain arrhythmias (irregular heartbeats).
Indications for non-selective beta blockers?
They are used to treat a wider range of conditions, including hypertension, angina, arrhythmias, migraines, tremors, and glaucoma.
What is a contraindication for beta blockers?
Asthma since blocking airway β2-receptors can cause severe and sometimes fatal bronchoconstriction in people with asthma.
What is drug type is atropine and what is it the first line treatment for?
Atropine is a muscarinic receptor antagonist, increasing heart rates in patients.
It is the first line treatment for sinus bradycardia.
What are adverse effects of digoxin and what should it not be prescribed with?
Digoxin may compromise optic vision, leading to yellowing of vision.
It may also lead to excessive depression of AV node conduction causing heart block.
It should not be prescribed with amiodarone.
What are the two types of calcium channel blockers and what medication shouldn’t they be used with?
The two types of CCBs include dihydropyridines (non-rate limiting) and rate-limiting calcium channel antagonists.
Rate limiting CCBs should not be used with BBs
What are examples of ACE inhibitors and their mechanism of action?
ACE inhibitors block the release of ACE enzyme from the lungs, preventing the conversion of AT I to AT II.
Examples of ACEIs include Ramipril and Lisinopril.
What are examples of Angiotensin receptor blockers and their mechanism of action?
ARBs are AT2 receptor blockers, blocking the receptor site and action of AT II at the adrenal gland, preventing vasoconstriction and release of aldosterone.
Examples of ARBs include Losartan.
ACEIs give a bad cough, and therefore ARBs are the better alternative.
What other adverse effects are there?
ARBs may cause portal hypertension and hyperkalaemia
Alpha-blockers such as Prazosin and Doxazosin are used for what scenario?
What other drug cannot be co-administered due to the risk of complete heart block?
Alpha blockers are used for vasodilation and acts as add on treatment for hypertension.
They may cause postural hypertension and should not be prescribed with beta blockers for risk of complete heart block.
What are the 2 diuretic types and how do they work?
Loop diuretics act on the ascending Loop of Henle, and blocks the Na/K/2Cl channel.
These include Furosemide.
Thiazide-like diuretics act on the distal convulated tubule, and blocks the Na/Cl channel, and includes examples such as bendroflumothiazide.
What are the adverse effects of diuretics?
Adverse effects of diuretics include:
Hypokalaemia
Hyperglycaemia
Increased uric acid leading to gout
Impotence
What are statins i.e. simvastatin prescribed for?
Statins are used in patients with hypocholesterolaemia or high risk TIA patients, to reduce their TDL and LDL count.
Mostly for prophylaxis of acute coronary events.
What are the adverse effects of statins?
Myopathy (muscular tissue disease)
Rhabdomylosis
What are antiplatelet drugs used for and what are some examples?
Antiplatelet drugs are used to prevent formation of platelet clots in causes of thrombosis.
They are also used to treat arterial white thrombuses.
Examples include Aspirin, Ticagrelor and Clopidogrel.
Adverse effects of antiplatelet drugs?
risk of haemorrhage
peptic ulcers
Risk of anticoagulant drugs?
risk of haemorrhage
What clinical scenarios would warrant the prescription of anticoagulants? Give examples of the drugs.
Anticoagulants are used for treatment of red venous thromboses.
Examples of anticoagulants include LMWH, Warfarin, Rivaroxavan and Dabigatran.
What can reverse the effects of anticoagulants?
Vitamin K
What are the processes of anticogulants such as Heparin, LMWH, Rivaroxiban, Warfarin and Dabigatran?
Warfarin blocks inactive factor X and factor II.
LMWH, Heparin blocks factor Va via antithrombin III.
Heparin also blocks active IIa by antithrombin III.
Rivaroxiban directly blocks factor Xa, and Dabigatran directly blocks IIa
What drug types are adenosine and amiodarone?
Anti-arrhythmic drugs
What are the side effects of long term Amiodarone use?
Long term amiodarone causes pulmonary fibrosis, thyroid disorders and peripheral neuropathy.
