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Flashcards in DRUGS Deck (74):

Thiazide Diuretics: Examples

Bendroflumethiazide, Indapamide, Chlortalidone


Thiazide Diuretics: Mechanism of Action

Blocks Na+/Cl- co-trasnporter of DISTAL convoluted tubule of kidney. Stops Na from being reabsorbed so water stays in DCT.

Also have vasodilating effects


Thiazide Diuretics: Indications

First-line treatment for HTN when CCBs are contraindicated (e.g. in oedema)
Also add on to ACEis and CCBs


Thiazide Diuretics: Dose, prescribing and route

PO, 2.5mg OD


Calcium Channel Blockers: Examples

Amlodipine, Nifedipine, Verapamil, Diltiazem


Calcium Channel Blockers: Mechanism of Action

Block entry of Ca to muscle cells (myocytes or arterial SMCs) to prevent contraction. They hence vasodilator and slowing of heart rate.


Calcium Channel Blockers: Types

DIHYDROPYRIDINES: Selective to vessels: help to vasodilator and reduce blood pressure (AMLODIPINE, NIFEDIPINE)
NON-DIHYDROPYRIDINES: Selective for cardiac tissue help to reduce contractility and heart rate (verapamil and diltiazem)


Calcium Channel Blockers: Indications

- First or second line for HTN
- First line for stable angina (reducing rate and contractility reduces mycote requirement)
- Verapamil and diltiazem are cardiac specific and so can be used for arrhythmias (AF)


Calcium Channel Blockers: Adverse effects

Leg swelling, flushing, headache and palpitations

Verapamil can cause constipation and worsen heart failure


Angiotensin Receptor Blockers: Examples

Losartan, Candesartan, Irbesartan


Angiotensin Receptor Blockers: Mechanism of Action

Produced in RAAS system. Angiotensin II acts on SMCs or arteries to cause vasoconstriction.
ARBs block the AT1 angiotensin receptor on SMCs
- Dilates efferent nephron arteries reducing pressure in kidney and limiting damage here
- Reducing aldosterone levels and hence increasing sodium and water excretion


Angiotensin Receptor Blockers: Adverse Effects

Hypotension, Hypokalaemia (due to aldosterone drop)
Renal failure


Angiotensin Receptor Blockers: Prescribing, Dose and Route

PO 50mg OD (12.5mg if for heart failure). Titrate up.
Second line HTN treatment (with ACEi or CCB), third line is to add a TZD.


ACEis: Examples

Ramipril, Lisonopril, Perindopril


ACEis: Mechanism of Action

Inhibits Angiotensin covering enzyme and so stops angiotensin II from being produced. Prevents vasoconstriction and so PVR drops. No aldosterone secretion and so water and salt are excreted more.
- Dilates efferent nephron arteriole limiting kidney damage


ACEis: Indications

- First line for HTN <55yo
- Useful in chronic heart failure
- Reduced risk of cardiac events in IHD
- Useful in diabetic nephropathy


ACEis: Prescribing, Dose and Route

PO 2.5mg OD (lower dose for heart failure)


Loop Diuretics: Examples

Furosemide and Butenamide


Potassium Sparing Diuretics: Examples

Spironolactone, Amiloride, Eplenerone


Potassium Sparing Diuretic: Mechanism of Action

Blocks aldosterone receptors in the kidney to decrease reabsorption of sodium and water in the kidney tubule. MAINTAINS REABSORPTION OF POTASSIUM (Spironolactone)


Potassium Sparing Diuretic: Indications

Rarely used as first line diuretics but used consequentially when the patient develops hypokalaemia
Spironolactone can also be used to treat excessive hair growth and acne in women and early puberty in boys
- HTN due to hyperaldosteronaemia (CONN'S SYNDROME)


Potassium Sparing Diuretic: Adverse Effects

Spironolactone: hyperkalaemia, nausea, vomiting, headache, rashes, dizziness, decreased libido and gynecomastia in men

Amiloride: GI upset, dizziness, hypotension and urinary symptoms

Be wary of effect of lithium and digoxin clearance


Potassium Sparing Diuretic: Route, Prescribing and Dose

Spironolactone is PO 25-50mg. Best to take in morning.
Amiloride is most often given as CO-AMILOFRUSE (contain amiloride and furosemide). Usually contain 2.5mg of amiloride and 20mg of furosemide


Warfarin: Mechanism of Action

Clotting factors 2, 7, 9 and 10 require vit K to be present, in its reduced form, to be synthesised by liver. Warfarin blocks the enzyme that reduces vitamin K (vitamin K epoxide reductase)


Warfarin: Indications

Heart valve replacement
Someone at high risk of blood clots


Warfarin: Adverse effects

Easy bruising and bleeding
Always stop 4 days prior to surgery (replace with heparin in hospital)


Warfarin: Dosage Control

Dose extremely variable. Decided by monitoring their International Normalised Ratio (INR).
INR = Patients PT/ Standard PT
Aim for INR 2.0-3.0 (3.5 if valve replacement)


Anti-Platelets: Examples

Aspirin and Clopidogrel


Anti-Platelets (Aspirin): Mechanism of Action

Aspirin is a COX inhibitor that is weakly more selective for COX-1. Inhibiting COX reduces production of prostaglandins which cause vasoconstriction and platelet aggregation


Anti-Platelets (Clopidogrel): Mechanism of Action

Binds to ADP receptors on platelets stopping them from aggregating


Anti-Platelets: Indications

ACS to help inhibit platelet aggregation and limits arterial thrombosis
- Long term preventing in pro-thrombotic disorders (high risk of MI)
- Reduce risk of thrombus in AF when warfarin or NOAC is contraindicated
- Clopidogrel used to prevent occlusion of stents
- Aspirin can be used for mild to moderate pain


Anti-Platelets: Adverse Effects & interactions

- GI upset and gastric ulceration, haemorrhage. High dose can cause tinnitus, hearing problems, hyperventilation due to bronchospasm and metabolic acidosis
CLOPIDOGREL: mostly to do with bleeding (can be serious if GI or intra-cranial). Dyspepsia and diarrhoea also common


Anti-Platelets: Route, Prescribing and Dose

PO (aspirin can be given per rectum if high dose needed)
ACS: loading dose of 300mg and follow-uo of 75mg
- Consider PPI with aspirin, encourage to take with food


Thrombolytics: Examples

Tissue Plasminogen Activator (TPA), Streptokinase


Thrombolytics: Mechanism of action

Drugs that break down blood clots that have already formed. Helps turn plasminogen into plasmin which lyses fibrin meshes. tPA is direct copy of endogenous enzyme


Thrombolytics: Indications



Thrombolytics: Adverse effects

Streptokinase has a very short half life. Over-bleeding and haemorrhage is risk
People can have hypersensitivity to streptokinase (sourced from bacteria).
tPA doesn't have many AEs and so is used preferentially


Thrombolytics: Route, Prescribing and Dose

IV infusion, 100mg over 3 hours
Time window for prescribing is small (Usually within 3-4 hours but trust dependent)


Heparin: Examples

Fondaparinux, Tinzaparin, Enoxaparin, Dalteparin


Heparin: Types

Most common is LMWH: inhibits factor Xa and thrombin (common pathway)

Also Unfractioned Heparin: activates antithrombin that then, in turn, inhibits factor Xa and thrombin


Heparin: Indications

LMWH given prophylactically and widely in hospital as part of VTE prevention pathways
LMWH and fondaparinux are commonly given in ACS care as well


Heparin: Route

Sc injection ideally in abdo wall


Heparin: Prescribing and Dose

VTE control: 40mg tinza or enoxaparin
- Higher doses used when in treatment pathway for ACS


NOACs: Examples

Rivaroxaban, Apixaban


NOACs: Mechanism of action

Work in a similar way to heparin then directly inhibit factor Xa in the coag cascade


NOACs: Indications

Prophylaxis for VTE (esp in patients with joint replacement)
Treatment of DVT and PE
Prophylaxis of stroke
Prophylaxis of clot in NON-VALVULAR AF


NOACs: Adverse effects

Bleeding is main AE
Hypotension, nausea and vomiting
Avoid in those with active bleeding, malignant neoplasms, oesophageal varices or anyone who's had surgery recently
Avoid in pregnancy
NOT LICENSED for use in people with prosthetic valves


NOACs: Route, Prescribing and Dose

PO, 2.5mg BD usually elevated to 10mg BD and then back down to 5mg BD maintenance dose


Amiodarone: Mechanism of Action

Blocks sodium, potassium and calcium channels and antagonises alpha AND beta adrenergic receptors. Reduces spontaneous depolarisation, slow conduction velocity (conductivity) and increases cells' resistance to depolarisation (refractoriness). Does this throughout myocardium and at AV node hence reducing ventricular contraction rate in AF


Amiodarone: Indications

Management of arrhythmias
Management of AF
Management of SVT, VT and VF


Amiodarone: Adverse effects

Can cause hypotension (if IV infusion). If used chronically can cause:
- Pneumonitis
- Bradycardia and AV block
- Hepatitis
- Photosensitivity and grey coloration of skin
- Thyroid abnormalities (Contains iodine)

**very long half life.
***lots of interactions: increase conc. of digoxin, diltiazem and verapamil


Amiodarone: Prescribing

Should not be offered long term due to adverse effects


Beta-Blockers: Mechanism of action

BETA RECEPTORS: Beta-2 in tubes and Beta 1 found in heart. When beta-1 are stimulated they increase rate and contractility of heart. BBs block this


Beta-Blockers: Examples

Atenolol, Propanolol, Bisoprolol, Metoprolol


Beta-Blockers: Indications

1. First line for IHD (angina and ACS): improve sx and prog.
2. First line for AF: stabilise heart beat and regain sinus
3.Chronic heart failure: decrease contractility and stop heart enlarging
4. First line for SVT: restore sinus rhythm
5. HTN: second line. Control renin secretion in kidney as well as vasodilator


Beta-Blockers: Adverse effects and interactions

Headaches, cold extremities, Fatigue, GI upset, Sleep disturbances, Impotence in men
DO NOT USE IN ASTHMATICS: bronchoconstriction can cause asthma attack (usually okay in COPD - use atenolol: good B1 selectivity)



Beta-Blockers: Route, Dose and prescribing

PO, 12.5mg TD then titrate up


Cardiac Glycoside: Examples



Cardiac Glycoside: Mechanism of action

Reduce contractility of the heart by blocking Na+/K+ pumps meaning Na+ accumulates in myocyte, therefore Ca can't move out of the cell (exchanged). High Ca means contractility increases.
Glycosides also increase parasympathetic tone and decrease conduction at AVN and hence decrease rate


Cardiac Glycoside: Indications

1. AF (increase parasympathetic tone and blocking at AVN sinus rhythm is established (BB better)
2. Heart failure (usually 3rd line after ACEi, BB and aldosterone agonist)


Cardiac Glycoside: Adverse effects and interactions

- Bradycardia
- Dizziness
- GI upset
- Rash
- Visual disturbances

*Narrow TPI. At too high dose can cause arrhythmias
**Dont give in heart block or arrhythmia patients
***reduce dose in renal failure
****be wary in electrolyte balance
*****be wary with loop and TZDs


Cardiac Glycoside: Route, prescribing and dose

PO (effect within 2 hours)
IV (effect within 30 mins)
Large volume of distribution: LOADING DOSE: 500micrograms followed by 250micrograms 6 hours later then 125-250microgram OD maintenance dose


Nitrates: Examples

Glyceryl Trinitrate (GTN), Isosorbide mononitrate


Nitrates: Mechanism of Action

Vasodilators which help to relieve sx of ischaemia. Converted to NO in body which is endogenous vasodilator: Increase production of cGMP reducing intracellular Ca which reduces contraction. Venous dilation reduces preload reducing cardiac work and myocardial O2 demand helping to relieve angina and cardiac failure.


Nitrates: Indications

1. GTN is short acting for treatment of acute angina and ACS
2. Isosorbide mononitrate is long action and used prophylactically for angina where BB or CCB not tolerated
3. IV nitrate used for pulmonary oedema +furosemide ++oxygen


Nitrates: Adverse Effects and Interactions

Vasodilatory effects:
- Flushing
- Headaches
- Dizziness
- Hypotension
*can build up a tolerance to them
**do not give in patients with severe aortic stenosis, might cause cardiovascular collapse. Avoid in hypotensive patients.


Nitrates: Route, Prescribing and Dose

Sublingual spray or tablet. GTN half life <5min
GTN can also be given IV (50mg/50mL)


Statins: Examples

Simvastatin, Atorvastatin, Pravastatin, Rosuvastatin


Statins: Mechanism of Action

Inhibit HMG CoA Reductase which is en enzyme involved in making cholesterol.
Encourage clearance of LDL and slightly increase HDL


Statins: Indications

1. 1ry prevention of cardiovascular disease. Always given in people >40yo with >20% risk of CVD in next 10 years
2. 2ry prevention of CVD (those that have already had an event)
3. Primary hyperlipidaemia and hypercholesterolaemia


Statins: Adverse Effects and Interactions

Headaches, GI upset
Myalgia: in severe cases can cause rhabdomyolysis
Can cause raise in liver enzymes
*use in caution in hepatic or renal impairment patients
**metabolised by CYP450 so drugs that act on this system (amiodarone, diltiazme and macrocodes will have an effect on serum levels)


Statins: Route, Prescribing and Dose

PO, 40mg OD (50mg for atorva). Higher doses are used for 2ry prevention


What is an Ionotrope?
Give some examples

A drug which changes the force of contraction.
Digoxin, Amiodarone, BBs


What is a Chronotrope?
Give some examples

A drug that changes the rate of contraction.
Beta-Blockers, Amiodarone, Digoxin