CPT 1- Drugs PDF

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Summary

DRUGs table. ...

Description

CPT 1: Drugs

Examples

Indications

ACE Inhibitors

Drug (Class)

Lisinopril, ramipril, quinapril, enalapril maleate

Hypertension, heart failure (treatment and prophylaxis).

Angiotensin II Receptor Blockers (ARBs)

Losartan, valsartan, candesartan

Atropine

Beta blockers (Class II)

Mechanism of action (general) Prevents vasoconstriction and release of aldosterone from adrenal cortex (from angiotensin II), ↓ BP

Mechanism of action (specific)

Counselling/adverse effects

Angiotensin-converting enzyme (ACE) inhibitorsreversibly inhibit the conversion of angiotensin I to angiotensin II (a potent vasoconstrictor). Widely distributed in body but particularly high in pulmonary epithelium. In kidney Ang II produced by intrarenal renin alsostimulates aldosterone release from the adrenal cortex. This exerts antinatriuretic and antidiuretic effects i.e. causes salt/water retention ACE inhibition exerts opposite effect.

- Most common SEpersistent dry cough. This is due to inhibition of bradykinin breakdown inflammatory mediator that causes vasodilation in smooth muscle (good for ↓ BP, not good for bronchi  irritation) - Can cause hypotensiondue to inhibition of ACE in vascular smooth muscle - May promote Na+ and H2O excretion (similar to diuretics)hyperkalaemia (particularly in patients with impaired renal function) - Also act as sympatholytics in CNS - Afro-Caribbean patients may respond less well to ACE inhibitors. - Contraindicated in pregnant/breastfeeding women

Hypertension, heart failure (treatment and prophylaxis). Alternative to ACEIs if not well tolerated

Ang II antagonist Prevents vasoconstriction, ↓ BP

AT1-receptorantagonistsblock the activation of angiotensin II AT1 receptors. Blockage of AT1 receptors directly causes vasodilation,↓ secretion of vasopressin and ↓production and secretion of aldosterone. The combined effect reduces blood pressure.

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2nd/3rd degree heart block

Atenolol, bisoprolol, carvedilol

Angina, hypertension, SA/AV node arrhythmias induced by stress/anxiety/exercise (sympathetic outputcirculating catecholamines)

Causes vagolysis i.e. ↓ in vagal tone by blocking muscarinic receptors Block β-adrenergic receptors- ↓ sympathetic activity reduces cardiac O2 demand

Enhances sinus node activity and blocks effects of acetylcholine at AV node ↓ refractory time and ↑speed of conduction through AV node. Antagonism of SNS ↓ HR, ↓ force of contraction, ↓ preload due to venodilation, ↓ afterload due to arterial dilation, ↑diastolic time (only get perfusion during diastole important in angina treatment). Blockage of β-adrenergic receptorsslow sinus rhythm, prolonged PR interval (no effect on QRS/QT intervals)

- Can cause hypotension due to ↓ binding of Ang II in vascular smooth muscle - May promote Na+ and H2O excretion (similar to diuretics)hyperkalaemia (particularly in patients with impaired renal function) - Contraindicated in pregnant/breastfeeding women Not as good as ACE inhibitors Insufficient doses may cause opposite effects- further slowing heart rate.

Also used in hyperthyroidism to ↓ anxiety/cardiac symptoms associated with ↑SNS stimulation.

Biguanides

Bile acid sequestrants

Metformin

Carvedilol: heart failure (nonspecific alpha/beta blocker) Hyperglycaemia

Cholestyramine, colestipol

Hyperlipidaemia (nothypertriglyceridaemia)

↑ glucose uptake ( utilisation in glycolysis) by skeletal muscle

Increased glucose uptake causes ↑ production of LACTIC ACID can cause lactic-acidosisif too much builds up. Liver is responsible for breakdown of LA, so contraindicated in patients with compromised liver function (includes alcoholics)

Prevent reabsorption of bile acids↑ excretion in

Lower LDL cholesterol and often given in combination with statins.

SE’s include: Nausea, diarrhoea, bronchospasm(NOT for use in asthmatics), bradycardia, hypotension, heart failure/heart block(can be used at low doses to treat HF). Can also cause HYPOGLYCAEMIA due to inhibition of β2-adrenoceptor stimulation of glucagon release glycogenolysis.

Metformin is drug of choice in obese individuals SE’s include: Lactic acidosis(muscle effects, rapid breathing) Contraindicated in those with liver/renal impairment, MI, uncontrolled congestive heart failure. Should NOT be used if there are any underlying gut problems.

NOTES: - ↓ blood viscosity(i.e. via anti-coagulants) causes a ↓ in peripheral resistance lowers the workload for the heart - PRELOAD= venoconstriction, AFTERLOAD= arterial constriction (↓ P & A ↓ O2 demand) - PPAR : Target of fish oils, fibrates. Controls genes involved in b-oxidation (exercise etc) PPAR : Master regulator of adipogenesis; target of thiazolidinediones (glitazones) PPAR : Fatty acid uptake (skeletal muscle)...