BASIC - CARDIOVASCULAR + DERMATOLOGY Flashcards
Names of loop diuretics?
Furosemide, bumetanide
Indications of loop diuretics?
Acute pulmonary oedema (with O2 and nitrates)
Chronic heart failure
Other oedematous states (renal and liver disease)
Mechanism of action of loop diuretics?
- Act on ascending limb of loop of Henle – inhibit Na/K/2Cl co-transporter (from lumen to epithelial cell)
- Stops water following by osmosis
- Dilatation of capacitance veins – reduces preload and improves contractile function of heart failure
Side effects of loop diuretics?
- Dehydration
- Hypotension
- Low electrolytes (Na, K, Cl, Ca, Mg)
- Tinnitus and hearing loss
Contraindications of loop diuretics?
- Dehydration/Hypovolaemia
- Hepatic encephalopathy (hypokalaemia cause/worsen coma)
Cautions of loop diuretics?
- Electrolyte disturbances (low K, Na)
- Worsens gout – inhibit uric acid excretion
Interactions of loop diuretics?
- Affect drugs excreted by kidneys
o E.g. lithium levels increase and digoxin toxicity by hypokalaemia - Increase ototoxicity and nephrotoxicity of aminoglycosides
Dose of loop diuretics?
o Oral/IV furosemide 40g
o Oral 1mg bumetanide (500mg if elderly)
o Oral doses taken in morning (second dose in early afternoon when BDS) to avoid nocturia
Communication to patient of loop diuretics?
o Medicine will cause urine to be passed more
o Aim for weight loss of no more than 1kg/day
Monitoring of loop diuretics?
o U&Es during treatment
Names of thiazide diuretics?
Bendroflumethiazide, indapamide, chlortalidone, metolazone
Indications of thiazide diuretics?
- Hypertension add-on (step 3)
- Alternative first-line hypertension when CCB cannot be used (HF, oedema)
Mechanism of action of thiazide diuretics?
- Inhibit Na/Cl co-transporter in distal convoluted tubule
- Prevents sodium and water reabsorption
Side Effects of thiazide diuretics?
- Hyponatraemia
- Hypokalaemia
- Cardiac arrhythmias
- Increase glucose, HDLs and triglycerides
- Impotence in men
Contraindications of thiazide diuretics?
- Hypokalaemia
- Hyponatraemia
- Gout
- Hypercalcaemia
- Addison’s Disease
- History of allergy to sulphonamides
Changes in renal failure of thiazide diuretics?
- Ineffective in eGFR<30
- Metolazone effective if eGFR<30
Changes in liver failure of thiazide diuretics?
- Caution mild-to-moderate
- Avoid in severe liver disease
Interactions of thiazide diuretics?
- NSAIDs reduce effectiveness
- Combination of loop and thiazide diuretics lower serum K
Dose of thiazide diuretics?
- Taken orally, regularly
- Indapamide 2.5mg OD used for hypertension
- Take in morning
Monitoring of thiazide diuretics?
U&Es before starting, 2-4 weeks into therapy and after change in dose
Names of K-sparing diuretics?
Amiloride (as co-amilofruse/co-amilozide), spironolactone, eplerenone
Indications of amiloride and spironolactone?
Amiloride - Hypokalaemia (arising from diuretic therapy)
Spironolactone - Ascites and oedema from liver cirrhosis, CHF, Hypertension (resistant), Nephrotic syndrome
Primary hyperaldosteronism
Mechanism of amiloride and spironolactone?
- Amiloride
o Weak diuretic but can counter-act potassium loss
o Inhibits Na and water reabsorption by ENaC in distal convoluted tubule - Spironolactone
o Competitively bind to aldosterone receptors affecting ENaC in distal convoluted tubule
o Increases potassium retention and increases water and Na excretion
Side effects of K-sparing diuretics?
- GI upset
- Dizziness, hypotension and urinary symptoms
- Hyperkalaemia
- Spironolactone only – gynaecomastia, jaundice, liver impairment, SJS (bullous skin eruption)
Contraindications of K-sparing diuretics?
- Severe renal impairment
- Hyperkalaemia
- Anuria
- Spironolactone – Addison’s disease
- Pregnancy and breast-feeding
Interactions of K-sparing diuretics?
- Do not combine with potassium supplements, aldosterone antagonists, ACEi, ARBs – risk of hyperkalaemia
- Dose adjustment of lithium and digoxin needed
Dose of K-sparing diuretics?
o Co-amilofruse tablet at strength 1:8 so state strength and dose as number of tablets taken daily
o Spironolactone = 100-200mg, increased up to 400mg
o Regular OD dose - take with food
o Take in morning to minimise nocturia
Communication to patients of K-sparing diuretics?
o Warn men possibility of growth and tenderness of tissue under the nipples and impotence - spironolactone
o Reversible
Monitoring of K-sparing diuretics?
o Serum potassium, U&Es
1 week after initiation/dose increase
Monthly for 3 months and then 3 monthly for a year
Then every 6 months
Names of ACE inhibitors?
Ramipril, Lisinopril, Perindopril
Indications of ACE inhibitors?
Hypertension (1st or 2nd line Rx)
Heart Failure (1st line)
Ischaemic Heart Disease
CKD
Mechanism of ACE inhibitors?
- Block action of ACE to prevent conversion of angiotensin 1 to angiotensin 2 (Angiotensin 2 is vasoconstriction and stimulates aldosterone secretion)
- Reduces peripheral vascular resistance (BP), dilates efferent glomerular arteriole (reduces intraglomerular pressure – slows CKD)
- Reduces aldosterone level – promotes sodium and water excretion (beneficial in HF)
Side effects of ACE inhibitors?
- Dry cough (1 in 10) – due to increased bradykinin
- Hypotension (especially with 1st dose – take in night)
- Hyperkalaemia
- Worsen renal failure
- Angioedema
Contraindications of ACE inhibitors?
- Renal artery stenosis
- AKI
- Pregnant and breastfeeding women
Dose changes in hepatic and renal impairment of ACE inhibitors?
Hepatic Impairment
- Caution
Renal Impairment
- Start with lower dose, adjust according to response
Interactions of ACE inhibitors?
- Avoid in potassium-elevating drugs (K+ supplements, potassium sparing diuretics)
- NSAIDs and ACEi – increased risk of renal failure
Dose of ACE inhibitors? (ramipril)
- Orally
- Starting dose 1.25-2.5mg ‘titrated up’ to a maximum 10 mg daily dose over a period of weeks
- First dose before bed to reduce symptomatic hypotension
Communication to patient of ACE inhibitors?
- Treatment to improve blood pressure and reduce strain on their heart
- Advise patients about common side effects
- Avoid taking over-the-counter anti-inflammatories (e.g. ibuprofen) due to the risk of kidney damage.
Monitoring of ACE inhibitors?
o Blood test monitoring as can interfere with their kidney function and upset potassium balance
o Check electrolytes and renal function before starting treatment
o Repeat these 1–2 weeks into treatment and after increasing the dose
If eGFR<25% increase and creatinine <30% increase - continue and recheck levels in 1-2 weeks
If eGFR>25% increase or creatinine >30% increase - stop drug or reduce dose to tolerated dose
If K>6 - stop ACEi
Names of beta-blockers?
Bisoprolol, Atenolol, Propranolol, Metoprolol
Indications of beta-blockers?
- 1st line in Angina, ACS
- CHF
- AF
- SVT
- Hypertension (Step 4)
Mechanism of beta-blockers?
- Beta1-adrenoreceptors found in heart mainly and Beta2-adrenoreceptors found in smooth muscle of airways and blood vessel
- Beta-blockers non-specific
o Atenolol, bisoprolol and metoprolol more B1 specific
o Propranolol non-selective - Mechanism:
o Reduce force of contraction and speed of conduction in the heart
o Prolong refractory period in AV node
o Reduce renin secretion
Side effects of beta-blockers?
- Fatigue, cold extremities, headache and GI upset
- Sleep disturbance
- Impotence in men
Contraindications of beta-blockers?
- Asthma (bronchospasm)
- Cardiogenic shock
- Hypotension
- Metabolic acidosis
- Prinzmetal angina
- 2nd degree Heart block
- Pregnancy
Cautions of beta-blockers?
- 1st degree heart block
- Hx of obstructive airway disease
- Myasthenia gravis
Dose changes in hepatic and renal impairment of beta-blockers??
Hepatic Impairment
- Caution – maximum 10mg in severe
Renal Impairment
- Reduce dose (max 10mg) if eGFR<20
Interactions of beta-blockers?
- Do not combine Beta-blockers and Non-DHP CCB – cause HF and bradycardia
Dose of beta-blockers?
- Oral, start low dose
- Bisoprolol in hypertension = 5-10mg
- Bisoprolol in HF = 1.25mg increased by 1.25mg weekly up to 10mg
- Take at same time each day OD
- Aim for HR of 55-60bpm
Monitoring of beta-blockers?
o Lung function (in patients with Hx of obstructive airway disease)
Cessation of beta-blockers?
Avoid abrupt withdrawal, especially in IHD
Causes rebound worsening of myocardial ischaemia
Names of nitrates?
Isosorbide mononitrate
Glyceryl trinitrate
Indications of nitrates?
- Acute angina, ACS
- Prophylaxis of angina (where BB, CCB not tolerated)
- IV nitrates in pulmonary oedema (with furosemide and oxygen)
Mechanism of nitrates?
- Nitrates converted into NO
- NO increases cGMP and reduces intracellular Ca in vascular smooth muscle cells
- Relaxation of venous capacitance vessels reduces preload
- Reduce cardiac work and myocardial oxygen demand
- Relaxation of systemic arteries, reducing arterial resistance and afterload
Side effects of nitrates?
- Flushing, headaches, light-headedness, hypotension, nausea and vomiting
- Sustained use – tolerance
o Nitrate free period important for 4-12 hours a day
Contraindications of nitrates?
- Severe aortic stenosis
- Cardiac Tamponade
- Constrictive pericarditis
- Cardiogenic shock
- Hypotension
Cautions of nitrates?
- HF due to obstruction
- Hypothermia
- Hypothyroidism
Dose changes in hepatic and renal impairment of nitrates?
Hepatic Impairment
- Caution in severe impairment
Renal Impairment
- Caution in severe impairment
Interactions of nitrates?
- Avoid phosphodiesterase inhibitors (Sildenafil) – hypotension
- Caution in antihypertensives – hypotension
Prescription of nitrates?
o GTN taken sublingually tablets or spray for immediate relief (half-life <5 mins)
o ISMN prescribed BDS/TDS for prevention of recurrent angina
o Available IR, MR, patches
o In ACS GTN given IVI:
Usually given 1mg/mL (50mg in 50mL), express starting dose as rate 1mL/hr
Increase GTN rate by 0.5mL/hr every 15-30 minutes until relieved
Communication to patients on nitrates?
o Take GTN before tasks to prevent angina
o Sit down and rest before and for 5 mins after taking GTN – hypotension
o GTN tablets need to be discarded after 8 weeks, so spray better for infrequent angina
o Ensure nitrate free period – usually overnight to prevent tolerance
Monitoring of nitrates?
o IV nitrates – measure BP and HR - >90mmHg systolic
Cessation of nitrates?
o Avoid abrupt withdrawal
Names of calcium channel blockers?
Dihydropyridines - Amlodipine, Nifedipine (vascular selective)
Non-dihydropyridines – Verapamil, Diltiazem (cardio-selective)
Indications of calcium channel blockers?
- Hypertension – Amlodipine
- Stable angina – amlodipine/Nifedipine
- Supraventricular arrhythmias (diltiazem and verapamil) – SVT, Atrial flutter and fibrillation
Mechanism of action of calcium channel blockers?
- Decrease Ca entry into vascular and cardiac cells
- Causes
o Relaxation and vasodilation in arterial smooth muscle (lowered blood pressure)
o Reduced myocardial contractility
o Reduce cardiac conduction (particularly AV node)
o Reduce myocardial oxygen demand
Side effects of calcium channel blockers?
- DHP
o Ankle swelling, flushing, headache and palpitations (caused by vasodilatation and compensatory tachycardia)
o Abdominal pain, nausea, vomiting - Verapamil
o Constipation, bradycardia, hypotension, heart block, cardiac failure - Diltiazem – any of the above
Contraindications of calcium channel blockers?
- Non-DHP – bradycardia, 2nd/3rd degree heart block, Wolf-Parkinson-White syndrome, hypotension, cardiogenic shock
- DHP - unstable angina, cardiogenic shock and severe aortic stenosis
Dose change in hepatic impairment of calcium channel blockers?
Hepatic Impairment
- Caution – start at low dose
Interactions of calcium channel blockers?
- Non-DHP – do not prescribe with Beta-blockers
Dose of amlodipine/diltiazem?
- Oral, OD (amlodipine)
- E.g. amlodipine 5-10mg OD for hypertension, diltiazem MR 90mg 12hr for angina
- MR swallowed whole, not crushed or chewed
Names of angiotensin receptor antagonists (ARBs)?
Losartan, Candesartan, Irbesartan
Indications of angiotensin receptor antagonists (ARBs)?
- When ACEi not tolerated: o Hypertension o HF o IHD o CKD