NS, CV and renal pharmacology Flashcards
What is the treatment for second and third degree heart block?
Emergency treatment required - Atropine (IV) or Isoprenaline (IV)
Class I Anti-arrhythmic drugs
Sodium channel blockers
Class II anti-arrhythmic drugs
Beta blockers
Class III anti-arrhythmic drugs
K+ channel blockers/Prolong A.P duration
Class IV anti-arrhrhymic drugs
Calcium channel blockers
What are the differences between Class Ia,b and C anti-arrhythmic drugs?
Differences due to recovery/unbinding of drugs
What is the main affect of Class I anti-arrhrhymic drugs?
Block Na+ channels to decrease phase 0 - depolarisaiob
Dysopyramide
Sodium channel blocker (Class 1A anti-arrhythmic drug) used to treat ventricular arrhythmias
Lidocaine (IV)
Sodium channel blocker (Class 1b anti-arrhrhymic drug) used in treatment prevention of ventricular tachycardia and fibrillation during and immediately after myocardial infarction
Flecainide
Sodium channel blocker (Class 1c anti-arrhrhymic drug) used to prevent paroxysmal atrial fibrillation and recurrent tachyarrythmias associated with abnormal conduction pathways
Amiodarone, sotalol, Bretylium
K+ channel blockers, prolong A.P depolarisation
What is Amidarone used to treat?
Tachycardia associated with WPW syndrome
What is Sotalol used to treat?
used in paraxysmal supraventricular dsyrthmias and suppresses ventricular ectopic beats, and short runs of ventricular tachycardia
outline the mechanism of CCB’s
act on L-type channels, shorten the plateau of the AP and reduce the force of contraction. Reduced Ca2+ entry reduces after depolarisation and thus suppresses premature ectopic beats
Veramapil
CCB
Diltiazem
CCB
outline the side effects of CCBs?
bradycardia, negative inotropic effect, constipation (verapamil), hypotension (diltiazem)
Loop diuretics, site of action
Act on thick ascending limb (TAL) of loop of Henle to inhibt Na+/K+/Cl-
Furosemide, Butetamide
Loop diuretics
Thiazides site of action
Distal tubule
Why might thiazides be preferred over loop diuretics?
Thiazides are less powerful than loop diuretics so preferred in treating uncomplicated hypertension. In contrast to loop diuretics thiazides reduce Ca2+ excretion and so is favourable in elderly patients
Thiazides mechanism of action
Bind to the Cl- site of distal tubular Na+/Cl- cotransport system inhibiting its action causing natriuresis with loss of Na+ and Cl-, results in reduced blood volume.
Clinical uses of thiazide diuretics
Hypertension, mild heart failure (loop diuretics preferred), severe resistant oedema, nephrogenic diabetes insipidus
Adverse effects of loop diuretics and thiazides
hypotension, gout, hypokalemia (caues dysrhythmias, increased digoxin toxicity and hyperglycaemia)
Potassium sparing diuretics- site of action
Act exclusively on distal parts of nephron: collecting tubule and collecting duct
Aldosterone antagonist - mechanism of action
Competitive inhibtion of intracellular aldosterone receptors, decreases the numbre of luminal Na+ channles and decreases number of basolateral Na+-K+-ATPases. This inhibits Na+ retention and K+ secretion
Spironolactone
Potassium sparing diuretic - aldosterone antagonist
Na+ channel blockers - mechanism of action
Inhibit Na+ re-absorption by blocking lumenal sodium channels and decreasing K+ excretion
Triameterene, Amiloride
Potassium sparing diuretic - Na+ channel blockers
Clinical uses of potassium sparing drugs
used with K+ losing diuretics, heart failure, primary aldosteronism (conns syndrome), resistant essential hypertension, secondary hyperaldosteronism caused by hepatic cirrhosis complicated by ascites
Osmoitic diuretics - site of action
Main effect is exerted on parts of the nephron that are FREELY permeable to water: proximal tubule, descending limb of the loop and collecting tubules
Osmotic diuretics - mechanism of action
Increase filtrate osmolairty, passive water reabsoprtion is reduced by the presence of non reabsorbable solute within the tubule
Clinical use of Osmotic diuretics
Used in emergency treatment of acutely raised intraocular or intracranial pressure
Clinical uses of carbonic anhydrase inhibitors
Glaucoma, altitude sickness, little use as a diuretic drug due to rapid tolerance
What is nephrotic syndrome?
Increased permeability of the glomerular basement membrane to proteins leading to proteinuria. Increases volume of interstitial fluid leading to tissue swelling and activation of RAAS.
Treatment of glomerular nephritis
Antihypertensive, loop diuretic, immunosuppresive
Consquences of glomerular nephritis
Acute renal failure, chronic renal failure, dialysis or transplantation
Acute Kidney Injury
Abrupt reduction in kidney function resulting in failure to maintain fluidm electrolye, and acid-base homeostasis. Decreased urine production and fluid-electrolyte imbalance.
Pre-renal causes of AKI
Causes that decrease effective blood flow to the kidney e.g. reduced cardiac output - heart failure, MI, bradycardia. Drugs - ACE inhibitors, NSAIDS
Renal causes of AKI
Blockage of renal vasculature = uric acid crystals, cholesterol emboli, vasculitis, endothelial damage (blood clots). Glomerulonenephritis Interstitial nephritis
Post renal causes of AKI
Urinary tract obstruction, benign prostatic hypertrophy, cancers/tumours, stones, non-emptying bladder, crystal deposition
Disopyramide, procainamine, quinidine
Class 1a antiarrythmic drugs - sodium channel blockers. Intermediate dissociation rate, leading to moderate decrease in phase 0 and increased QRS and QT interval Used to treat AF (triggered by vagal overreactivity) and VT
lidocaine, mexiletine
Class 1b anti-arrhythmic drugs -sodium channel blockers. Fast dissociation rate, decreased AP duration and QT interval. Used to treat and prevent VT and VF immediatley after Myocardial infarction
Flecainide, Moncizine, propafenone
Class 1c anti-arrhythmic drugs, blocks with slow dissociation rate causing large decrease in phase 0, leading to increased QRS and QT interval. Used to treat AF and recurrentt tachycardias associated with adnormal conduction pathways and WPW syndrome
Class 1a anti-arrhythmic drugs side effects
Atropine like (urinary retention, dry mouth, blurred vision, constipation) and Quinide causes syncope (due to triggering torsades de pointes)
Class 1b anti-arrhythmic drugs side effects
CNS, drowsiness, disorientation and convulsions
Beta blockers mechanism
Block cardiac B1 adrenoreceptors to reduce sympathetic drive to the heart, decreasing heart rate
Propranolol
Non selective B antagonist, long acting, oral
Timolol
Non selective B antagonist, used to treat glaucoma (decreases AH formation)
Atenolol, bisoprolo, metoprolol
B1 Selective antagonist
Pindolol
B1 Selective partial agonist
Nevbivolol
B1 selective antagonist and also increases NO (leading to less fatigue, bradycardia,and impotence)
Labetalol
Mixed alpha/beta adrenergic antagonist
Carvedilol
Mixed Alpha1/beta antagonist
Clinical uses of beta blockers
Rate control in SVT, rate and rhythm control in AF and flutter, VT
Adverse effects of B blockers
Bronchospasm (caution in asthma), negative inotropic effect, bradycardia, fatigue, increased risk of hypoglycaemia (diabetics)
Sotalol, amiodarone, bretylium
Class 3 anti-arrhythmic drugs-prolong AP duration by prolong phase 3 by blocking K+ channels
Amidarone
K+ channel blocker. Also a modest Na+ and Ca2+ blocker and alpha adrenergic receptor antagonist and decreases cardiac B1 adrenergic receptor expression. When given orally has slow onset (up to 3 weeks) and a very long plasma half life
Amidarone side effects
thyroid abnormalities, corneal deposits, pulmonary disorders, skin pigmentation
Class 3 anti-arrhythmic drugs clinical uses
SVTs, WPW syndrome, ventricular tachycardias
Sotalol
Class 3 anti-arrhythmic also a non selective B blocker. Lacks the adverse ADRs seen in amidarone
Verapamil, Diltiazen
Class IV anti-arrhythmic drugs. Calcium channel blockers to slow down AVN conduction
Therapeutic uses of Class IV anti-arrhythmic drug
paroxsmal SVT, AF (but NOT if due to WPW)
Class IV anti-arrhythmic drug side effects
bradycardias, negative inotropic effect, constipation (verapamil), hypotension (more with diltazem)
Ist line treatment for hypertension <55 years
ACE inhibitor or angiotensin receptor AT1 blockers
Captopril, Enalapril
ACE inhibitors
ACE inhibitors effects
reduce TPR with little effect on HR or cardiac output
ACE inhibitors adverse effects
Dry cough (due to accumulation of bradykinin)
Losortan, Candesartan
Angiotensin receptor (AT1) blockers
?Why mgiht AT1 blockers be preffered over ACE inhibitors
NO dry cough - no bradykinin accumulation
Aliskiren
Renin inhibitor
Renin inhibitors
e.g. Aliskiren. reduces plasma renin activity by binding and inhibiting activity
Contraindication of RAAS inhibitors
In pregnancy (due to fetotoxicity)
Common ADRs of RAAS inhibitors
hypotension (with thiazides), hypersemsitvity (head & neck angioedema), hyperkalaemia
1st line hypertension treatment in African/Carribbean and elderly (>55 years)
Calcium channel blockers
Nifedipine, Amlodipine
CCB, dihydropines, act preferentially on vascular smooth muscle, use in hypertension and angina
Phenylalkylamines
Verapamil - CCB act on cardiac preferentially
Benzothiazepines
Diltiazem, CCB with an intermediate effect on cardiac and smooth muscle
ADRs of Calcium channel blockers
Postural hypotension, flushes/tremors (nifedipine), AV block and negative ionotropic effects (verapamil, diltiazem)
Treatment for hypertension when ACEi/CCBs do not work?
Also give patient diuretics
Treatment in resistant hypertension
B Blockers and alpha antagonists
Statins, fibrates, bile-acid binding resins
Lipid lowering drugs
Statins mechanism
inhibits HMG-CoA reductase (key enzyme in cholestrol production)
Simvastatin, Atorvastatin, Pravastatin
Statins
Clinical uses of Statins
Primary and secondary prevention of CHD, (in patients with chronic kidney disease, diabetes type 1 and 2) familial hypercholesterolaemias, in children (>10years)
Contraindications in statins
In pregnancy
Statins ADRs
Muscle. (more serious: myopathies, hepatotoxicity)
Fibrates mechanism and effects
activator of peroxisomal proliferator activator receptor (PPARalpha) leads to increasedity, lipoprotein lipase activity and increase HDL synthesis
Clinical uses of Fibrates
In combination with statins/ in various dyslipidaemias
Fenofibrate, gemfribrozil
Fibrates (lipid lowering drugs)
Colestyramine, cholestipol
Bile acid binding resins (lipid lowering drugs)
Bile acid binding resins mechanism and effects
Enhance plasma cholesterol clearance via enterohepatic circulation. Get decrease in LDL (but no increase in HDL and triglyceride :( )
Clinical uses of bile acid binding resins
In patients with liver disease/pregnancy (with caution) when statins are not recommended
Ezetimibe
Lipid lowering drug, decreases cholesterol absoroption
Nicotinic acid/Niacin
Lipid lowering drug
Aspirin
COX-1 Inhibitors (antiplatlet agent)
Clopidogel mechanism
Antagonists of ADP Receptors (antiplatlet drug). Reduced expression of GPIIb/IIIa leads to platlet aggregation
Dipyridamole
Phosphodisterase inhibitors
ABCIXIMAB, Eptifibatide, tirofiban
Glycoprotein IIb/IIIa receptor inhibitors
Aspirin therapeutic uses
Primary prevention of ACS (in stable angina):Low dose Aspirin 75-150mg/day
In unstable angina: higher loading doses 150-300mg
Secondary prevention of MI = in combination with ACEI, statins and B blockers
Aspirin Side Effects
GI bleeding, Cerebral Haemorrhage
Clopidogrel clincial uses
Secondary prevention of MI (with aspirin or alone)
Anticoagulant mechanism of Heparin
Binds reversibly to to antithrombin III (ATIII) and greatly accerlates the rate at which it inactivates coagulation enzymes thrombin and factor Xa
Side effects of Heparin
Bleeding, immune thrombocytopenia, osteoporosis, hypersensitivity
Protamine Sulfate
Herpain antagonist (IV admin) used to to stop bleeding caused by heparin
Fondapariunux
Synthetic pentasaccheride inhibitor of activated factor Xa
Fondaparinux clinical uses
Acute coronary syndromes (unstable angina, NSTEMI, STEMI), stroke, deep-vein thrombosis, pulmonary embolism, prophylaxis of venous, thromboembolism follwoing orthapedic surgery
Enoxaparin
Low molecular weight Heparin
Hirudin, Bivalirudin
Direct thrombin inhibitors
Direct thrombin inhibitors therapeutic uses
Prevention of stroke and systemic embolism. Prophylaxis of venous thromboembolism (After hip or knee replacement surgery)
Rivaroxaban
Selective factor Xa inhibitor
Warfain
Oral anticoagulant. Inhibits Vitamin K reductase
Warfain -drug interactions
Antibiotics (decreased vitamin K avalibilty) excess alcohol (increases warfain), drugs inhibiting hepatic drug metabolism, NSAIDS (increase internal bleeding) Hypothyroidism (decreases warfain) and Hyperthyroidism (ncrease warfain)
Warfain: side effects and contraindication
Bleeding.
Teratogenic (avoid in 1st trimester in pregnancy)
Clinical uses of anticoagulants
treatment of unstable angina (NSTEMI), Prophylaxis of venous thromboembolism,
Alteplsae
fibrinolytic agent - recombinant tPA. Prevents conversion of plasminogen to plasmin
Reteplase
Fibrinolytic agents- recombinant tPA prevents conversion of plasminogen to plasmin
Streptokinase
fibronlytic agent
Urokinase
fibrinolytic agents
Tranexamic acid
anti-thrombolytic
First line treatment of heart failure
ACE inhibitor +B-blocker + Diuretic
Digoxin, Oubain
Cardiac glycosides
Milrinone, Enoximone
Phoshodiesterase type 3-inhibitors cardiac selective
Minoxidil, Diazoxide, Nicorandil
Potassium (ATP-sensitive) channel activators (openers)
Uses and effects of phoshodiesterase inhibitors in CHF
Use: short term treatment in acute decompensation of CHF
Effects: increased CO, reduced right atrial pressure, reduced TPR, overall has little affect of HR and BP
Phosphodiesterase inhibitors side effects
Nausea, vomiting, liver abnormalities, thrombocytopenia, lethal arrthymias (with prolonged use)
Glyceral trinitrate, isosorbide dinitrate, isosorbide mononitrate, sodium nitroprusside
Nitrates, and nitric oxide releasing drugs
Ivabradine
I (funny) current inhibitors (SA node)
Ranolazine
blocker of persistent cardiac sodium channels
Moxonidine
Imidazoline I1 receptor agonists
Levosimendan
Calcium sensitising positive inotropes
Loop diuretics. Site of action
Thick ascending limb of the loop of henle
Loop diuretics. Mechanism
Inhbition of the luminal Na+ /K+/2Cl- cotransporter
Furosemide, Bumetanide
Loop diuretics
loop diuretics - therapeutic uses
For treatment of salt and water overload in: acute pulmonary oedema, CHF, renal failure, nephrotic syndrome.
Liver cirrhosis with ascites
Hypertension complicated by renal impairment
Thiazides site of action
early distal tubule
Thiazides mechanism
Inhibition of Na+/Cl- transporter
Bendroflumethiazide, Chlorothiazide
Thiazides
Chlortalidone, Indapamide, Metolazone
Thiazide-like drugs
Thiazides therapeutic uses
hypertension, in mild heart failure, severe resistant odema, prevention of kidney stone formation in idiopathic hypercalcicuria, nephrogenic diabetes insipidus
Adverse effects of loop diuretics and thiazides
Hypotension, Gout, Hypokalaemia (Dysrhythmias, increased digoxin toxicity, hyperglycaemia)
Spironalactone, Epleronone
Aldoesterone antagonists (Potassium sparing diuretic)
Amiloride, Triamterene
Na+ channel epithelial blockers
Potassium sparing diuretics therapeutic uses
To prevent hypokalalemia, heart failure, resistant essential hypertension, aldosteronisms
Adverse effects of potassium sparing diuretics
Main= hyperkalaemia (more common in patients with renal diseases)
Mannitol
Osmotic diuretic
Mechanism of osmotic diuretics
Increase filtrate osmolarity. decreasing passive water reabsorption. Act of parts of the nephron freely permeable to water: Proximal tubule, descending limb of loop of henle, collecting tubule (in the presence of ADH)
Osmotic diuretics therapeutic uses
In acute renal failure.
Non renal uses: in emergency treatment of raised intracranial and intraocular pressure (glaucoma)
Acetazolamide
Carbonic anhydrase inhibitors
Carbonic anhydrase inhibitors clinical uses
Glaucoma, alitude thickness - little use as a diuretic drug due to rapid tolerance
Phenylephrine - site of action
alpha 1 selective agonist
Phenylephrine and Methoxamine uses
Selective Alpha 1 agonists cause smooth muscle constriction, used as nasal decongestants
Methoxamine
Selective alpha 1 agonist
Clonidine - site of action and effects
Selective alpha 2 agonist prevents NA release and hence reduces BP used as an antihypertensive
Dobutamine - site of action
B1 agonist
Dobutamine effects and uses
Dobutamine is an B1 agonist which increases cardiac contractility and so is used to treat cardiogenic shock
Adrenaline - therapeutic uses
Cardiac arrest and anaphylatic shock
Terbutaline -site of action
B2 agonist
Carbidopa
Inhibits NA synthesis by inhibiting DOPA decarboxylase. Used to treat parkisons disease alongside Levodpa
alpha-methyl-p-tyrosine
Inhibits tyrosine hyroxylase, inhibiting synthesis of NA - prossible us in phaechromocytoma
Isoprenaline
NON SELECTIVE Beta agonists
Oxymetazoline
NON SELECTIVE alpha agonist
Doxazocin, Prazosin - site of action
Selective alpha 1 agonists
Effects of Prazosin
Alpha 1 antagonist causing vasodilation and fall in aterial pressure (smooth muscle relaxation of bladder)
Yohimbine - site of action
Selective alpha 2 antagonist
Amphetamine, Tyramine
Indirectly acting sympathimimetic. Substrate for NET - rapidly displaces NA and increases NA in the synapse.
Cocaine, impramine
Inhibits NET -and therefore NA uptake, increasing NA in synapse
Guanethidine
Substrate for NET and VMAT. Displaces NA slowly (high doses will destory neurones)
Reserpine
Inhibits VMAT and therefore vesicular NA uptake. Free NA is metabolised by MAO
Side effects of Reserpine
Depression and parkinsonism
NA is metabolised by what two enzymes
Monoamine Oxidase (MAO) and Catechol-O-methyl transferase
Alpha-methyldopa
False NA precursor. Metabolised to methyl-NA acts as a alpha 2 agonist (this inhibits release of NA), used to treat pregnancy induced hypertension.
Carbachol
Muscarinic receptor agonists
Bethanecol
Muscarinic agonist - use to assist bladder empyting or to stimulate GI
Pilocarpine
Muscarinic receptor agonist - selectivity for constrictor pupillae, sweat, salivary, lacrimal. (minimal activity on smooth muscle and heart) Used to treat glaucoma. Stable compound actions last for one day.
Oxotremorine
Muscarinic agonist
Methacholine
Muscarinic receptor agonist
Atropine
NON Selective muscarinic antagonist
Clinical uses of Atropine
Adjunct anaesthia, treat anticholinsterase poisoning, bradycardia, GI hypermotility
Atropine side effects
Urinary retention, dry mouth, blurred vision, constipation
Scopolamine
Non selective muscarinic receptor antagonist.
Pirenzipine
M1 selective antagonist - treatment for peptic ulcers
Ipratropium
Non selective muscarinic antagonist
What is Ipratripiom used to treat?
Irritant induced bronchospasm by inhilation/nebulisers, asthma, bronchitis, COPD
Tioptropium
Simular to Iproatropium but with improved PK. Binds to all muscarinc receptors - but with so M3 selectivity
Oxybutynin
M3 selective antagonist
Nicotinine
Stimulates autonomic ganglia, leads to tachycardia, increased BP and increased secretions
Trimetaphan
Blocks nicotinic receptors and therefore action of ACH. used for emergency lowering of blood pressure
Hexamethonium
Blocks channels on autonomic ganglia - doesnt not compete with ACh
Hemicholinium
Blocks the uptake of choline
Botulinum toxin
Prevents vesicles fusing and releasing ACh (Botox)
Vesamicol
Vesamicol acts presynaptically by inhibiting ACh uptake into synaptic vesciles leads to empty vesicles fusing with neuron membranes and reducing ACh release.
Tubocurarine
non depolarising competitve nACh receptor antagonist
Gallamine
Non depolarising competitive nACh antagonist - synthetic analogue of tubocuraine
Pancuronium
non depolarisng competitive nACh antagonist - synthetic analogue of tubocuraine
Suxamethonium
Nicotinic acetylcholine receptor agonist, depolarizing neuromuscular blocker, resulting in persistent depolarization of the motor end plate. Used to induce short term muscle relaxation and short term paralysis
α-Bungarotoxin
Bind irreversibly and competitively to the nACh receptors causing paralysis and respiratory failure
Triethylcholine
Acts presynaptically. It is a drug that mimics choline (false transmitter) and causes failure of cholinergic transmission by interfering with synthesis of acetylcholine in nerve endings.
Streptomycin
Inhibits Ca2+ entry presynaptically
Neomycin
Inhibits Ca2+ entry presynaptically
ß-Bungarotoxin
Acts pre-synaptically to block ACh release
Neostigmine
Parasympathomimetic that binds and inhibits acetylcholinesterase. Used in people with myasthenia gravis.
Edrophonium
Anticholinesterase reversible inhibitor
Physostigmine (Eserine)
Physostigmine is a parasympathomimetic, specifically, a reversible cholinesterase inhibitor which effectively increases the concentration of acetylcholine at the sites of cholinergic transmission. Physostigmine is used to treat glaucoma. Because it crosses the blood-brain barrier, it is also used to treat the central nervous system effects of atropine overdose and other anticholinergic drug overdoses
Disopropyl fluorophosphate (DFP)
Diisopropyl fluorophosphate is a parasympathomimetic drug irreversible anti-cholinesterase and has been used in ophthalmology as a miotic agent in treatment of chronic glaucoma
Sarin
Inhibitor of anticholinisterase
Pralidoxime
Dyflos/Sarin antidote