Dose. Route. Units. Given. Special situations. Dose. Route. Units. Given. Special situations

Transcription

1 Chapter 3 Cardiology Georgia Woodfield ASPIRIN FONDAPARINUX 300 once only in acute MI 75 in primary/ secondary prevention of thrombus formation and thromboembolic disease or PR; can also be given via nasogastric tube Once daily May predispose to GI bleeding. Can cause a hypersensitivity reaction with bronchospasm, rhinorrhoea, urticaria and angioedema. 2.5 in acute MI once daily for up to 5 days SC Once daily Increased bleeding risk. Do not use in severe renal failure (egfr <30 ml/min). MORPHINE SULPHATE for chest pain CLOPIDOGREL 300 stat (in acute MI) then 75 daily in primary/ secondary prevention of thrombus formation, can also be given via nasogastric tube Once daily Increases bleeding risk. IV; different formulations of morphine can be given via different routes (see Chapter 7) No maximum; dose is titrated according to response, and presence of any signs of opiate toxicity such as respiratory depression and decreasing consciousness Regular opiate users may have very high requirements, whereas opiate naïve patients may find 2.5 sufficient. Essential Practical Prescribing, First Edition. Georgia Woodfield, Benedict Lyle Phillips, Victoria Taylor, Amy Hawkins and Andrew Stanton by John Wiley & Sons, Ltd. Published 2016 by John Wiley & Sons, Ltd.

2 METOCLOPRAMIDE 10 or IV Up to three times in 24 hours Metoclopramide can cause an oculogyric crisis due to its effect on dopamine receptors (see Chapter 7). This occurs particularly in young women, although is rare. Procyclidine reverses this unwanted symptom. GLYCERYL TRINITRATE (GTN) SPRAY 2 sprays (each spray is 0.3 ) Sublingual Sprays at a time, repeat as required Causes headache due to vasodilation of vessels in the head (as well as the desired coronary vessels). This can limit use. GLYCERYL TRINITRATE (GTN) INFUSION 1 10 per hour IV As an infusion over 24 hours Titrate to blood pressure, as it will invariably drop blood pressure due to vasodilation. Ideally aim for the maximum dose, or dose that will adequately control pain without dropping BP to less than 90 systolic. Again, it can cause headache. FUROSEMIDE 40 as a starting point IV; can be given but will take longer to work As required If patient is already on high doses of furosemide, 40 may not be enough. Consider doubling patient s usual maintenance.

3 GLYCERYL TRINITRATE (GTN) SPRAY 2 sprays (each spray is 0.3 ) Sublingual Sprays at a time, repeat as required Causes headache due to vasodilation of vessels in the head (as well as the desired coronary vessels). This can limit use. GLYCERYL TRINITRATE (GTN) INFUSION 1 10 per hour IV MORPHINE SULPHATE for pulmonary oedema IV; different formulations of morphine can be given via different routes (see Chapter 7) No maximum however this is being given for vasodilation and calming effect, therefore high doses are not required. is titrated according to response, and consciousness levels Monitor carefully for respiratory depression or decreasing consciousness as this is very detrimental to a patient already in respiratory distress. As an infusion over 24 hours Titrate to blood pressure, as it will invariably drop blood pressure due to vasodilation. Ideally aim for the maximum dose, or dose that will adequately control pain without dropping BP to less than 90 mmhg systolic. Again can cause headache. METOCLOPRAMIDE 10 or IV Up to three times in 24 hours Metoclopramide can cause an oculogyric crisis due to its effect on dopamine receptors (see Chapter 7). This occurs particularly in young women, although is rare. Procyclidine reverses this unwanted symptom.

4 ENALAPRIL BISOPROLOL 2.5 aiming for Start at 2.5 BD, aiming for BD 1.25 starting, aiming for 10, aiming for 10 ACEIs will cause a degree of renal impairment. Allow a <50% deterioration in baseline creatinine; however, renal function that is poor may limit dosing. None CARVEDILOL RAMIPRIL 2.5, aiming for 10 Start at 2.5, aiming for 10 ACEIs will cause a degree of renal impairment. Allow a <50% deterioration in baseline creatinine; however, renal function that is poor may limit dosing. LISINOPRIL 2.5 aiming for BD starting dose BD, aiming for BD None METOPROLOL 50 starting, aiming for 200, can also be given IV but not for chronic LVF, aiming for 200 None Start at 2.5, aiming for ACEIs will cause a degree of renal impairment. Allow a <50% deterioration in baseline creatinine; however, renal function that is poor may limit dosing.

5 SPIRONOLACTONE FUROSEMIDE 25 starting dose, aiming for (max dose daily, discuss with senior) or BD Note that this chronic heart failure dose is different to the higher dose used in chronic liver disease and other requiring more significant diuresis. EPLERENONE 25 starting dose, aiming for 50 Titrate dose to tolerance, blood pressure and electrolyte control. Heart failure patients will be on other medications that are beneficial to survival, hence furosemide dose must fit around the optimum doses of these medications as first priority. BENDROFLUMETHIAZIDE 2.5 Eplerenone is used in preference to spironolactone post-mi. Useful in severe heart failure where resistance to loop diuretics has occurred (see Section Diuretics: Rationale and Evidence).

6 VALSARTAN BISOPROLOL 40 aiming for 160 BD 2.5 (up to maximum of 10 ) Start at 40 BD, aiming for 160 BD ARBs (like ACEIs) will cause a degree of renal impairment. Allow a <50% deterioration in baseline creatinine; however, renal function that is poor may limit dosing. DIGOXIN 250 micrograms micrograms Note this dose differs from the higher doses that may be used for rate control of atrial fibrillation. Digoxin levels must be monitored as it has a narrow therapeutic window (see Digoxin Toxicity). Levels are best taken 7 10 days after starting treatment. Do not use in asthma/copd, uncontrolled heart failure, sick sinus syndrome, heart block, hypotension or severe peripheral vascular disease. ORAL METOPROLOL 50 TDS; can give up to 300 daily in divided doses Do not use first line in asthma/ COPD, uncontrolled heart failure, sick sinus syndrome, heart block, hypotension or severe peripheral vascular disease.

7 IV METOPROLOL 1 5, give in 1 aliquots max total dose is 15 IV Give, then wait 5 10 minutes, repeat if no response 5 is a common dose, but it is less risky to give smaller doses and repeat rather than give the full 5 at the start Do not use first line in asthma/ COPD, uncontrolled heart failure, sick sinus syndrome, heart block, hypotension or severe peripheral vascular disease. DIGOXIN 500 microgram loading dose 2 (separated by 6 hours) or IV micrograms Give second dose after 4 6 hours then continue daily oral maintenance dose of micrograms once daily May be used first line for AF in the elderly, immobile or where beta-blockers are contraindicated. Check digoxin levels after hours as maintenance dose may need adjustment. Typically, digoxin levels should be ng/ml. Do not use in heart block, Wolff Parkinson White syndrome, ventricular tachycardias (VT) as it may potentiate the use of the abnormal conduction pathways by slowing the atrioventricular (AV) node (normal) conduction.

8 DILTIAZEM 60 or IV TDS Do not give in heart failure, hypotension, sick sinus syndrome, bradycardia, 2nd or 3rd degree heart block (without pacemaker), AF with WPW, VT, pregnancy and breast feeding. Caution with beta-blockers risk of bradycardia, AV block and arrhythmias. NB: there are numerous longeracting maintenance formulations where brand name must be specified, e.g. Adizem-SR and Tildiem LA. Seek advice from senior/ cardiologist if you are unfamiliar with this drug. VERAPAMIL 40 oral or 5 IV or IV TDS Do not give in heart failure, hypotension, sick sinus syndrome, bradycardia, 2nd or 3rd degree heart block (without pacemaker), AF with WPW, VT, pregnancy and breast feeding. Do not give with beta-blockers risk of bradycardia, AV block and arrhythmias. Seek advice from senior/ cardiologist if you are unfamiliar with this drug.

9 ADENOSINE 6 IV Stat. If ineffective, repeat with 9, then 12 if required Must be given via large-bore cannula in antecubital fossa and flushed immediately with 5 10 ml normal saline otherwise it will not be effective. Do not use in Wolff Parkinson White syndrome or where there is a known aberrant pathway. Adenosine will block the AV node and therefore potentiate conduction through the abnormal pathway in these. Adenosine can precipitate AF due to its effect of atrial tissue. Where there is an aberrant pathway present, this can precipitate VT or VF due to conduction of AF down the aberrant pathway. Contraindications: asthma or bronchospasm from other causes. AMIARONE first dose 300 loading dose IV via a central line (or at very least through large bore cannula in antecubital fossa check with local guidance) Over 1 hour Irritant to blood vessels, hence preferable to give IV amiodarone via a central line. If it is given via a peripheral cannula and then extravasates, it causes painful inflammation to skin. Can cause hypokalaemia and hypotension when given IV. Can cause severe hepatocellular toxicity, even acutely. Can cause arrhythmias due to the fact it can prolong the QT interval, hence use in extreme caution with other drugs that cause prolonged QT. Contraindications: sinus bradycardia, sinoatrial heart block (unless pacemaker fitted), iodine sensitivity. AMIARONE second dose 900 prolonged loading dose, given after the first 300 loading dose has run through IV via a central line Over 23 hours As above. Maximum dose is 1.2 g in 24 hours.

10 maintenance AMIARONE MAGNESIUM SULPHATE 200 maintenance dose oral Three times daily for 1 week then twice daily for 1 week then once daily Different cardiologists may alter this typical regimen of oral dosing, also practices in different trusts vary. Amiodarone has many longterm side effects, many of which are irreversible. It is a toxic and unpleasant drug. See Section Amiodarone: Essential Pharmacology for numerous side effects and cautions. 4 8 mmol (1 2 tablets) of magnesium glycerophosphate mmol (there is generally 4 mmol in one tablet) Up to TDS There is a significant interrelationship between the plasma concentrations of magnesium and potassium, where abnormalities of either can cause arrhythmias. Potassium levels should therefore also be checked at the same time, and potassium replaced if needed. Main things to remember are: Arrhythmogenic Check thyroid and liver function tests every 6 months Can cause hypokalaemia Check colour vision. MAGNESIUM SULPHATE 2 g IV grams over 2 hours This dose is for rapid replacement of Mg rather than everyday prescribing.

11 TASSIUM CHLORIDE mmol of KCl in 1 L of 0.9% saline IV mmol No faster than 10 mmol KCl per hour (max rate) KCl given neat would cause fatal arrhythmias, hence it is always diluted in saline 0.9% or dextrose 5% in a premixed fluid bag and given slowly. Nurses no longer make up the fluid bags on the ward for fear of concentration errors. This situation may be different in intensive care settings, but even in ITU the pharmacy tends to mix the fluid for non-standard potassium prescriptions. There is a significant interrelationship between the plasma concentrations of magnesium and potassium, where abnormalities of either can cause arrhythmias. Magnesium levels should therefore also be checked at the same time, and Mg replaced if needed. ATROPINE 0.5 IV Stat Give up to 3 if ineffective at first May be ineffective in third-degree heart block. If an overdose is given, the antidote is physostigmine or pilocarpine. Side effects are dose related: blurred vision, dry mouth, urinary retention. Can cause confusion in the elderly. RAMPRIL ACEIs will cause a degree of renal impairment. Allow a <50% deterioration in baseline creatinine; however, renal function that is poor may limit dosing. Contraindicated in renal artery stenosis, due to substantial reduction on glomerular filtration rate, leading to severe and progressive renal failure.

12 ENALAPRIL LOSARTAN ACEIs will cause a degree of renal impairment. Allow a <50% deterioration in baseline creatinine; however, renal function that is poor may limit dosing. Contraindicated in renal artery stenosis, due to substantial reduction on glomerular filtration rate, leading to severe and progressive renal failure. Note this is a higher dose than when used for chronic heart failure (12.5 ). can be up-titrated to 100. Use with caution in renal artery stenosis. Use with caution in chronic renal impairment; contraindicated where egfr <60 ml/min/1.73 m 2. LISINOPRIL ACEIs will cause a degree of renal impairment. Allow a <50% deterioration in baseline creatinine; however, renal function that is poor may limit dosing. Contraindicated in renal artery stenosis, due to substantial reduction on glomerular filtration rate, leading to severe and progressive renal failure. CANDESARTAN 8 Oral Max dose is 32. for heart failure is usually lower (4 starting dose). See losartan for cautions.

13 ATENOLOL FELIPINE This is a lower dose than for arrhythmias and angina (up to 100 daily). Contraindicated in asthma and COPD with bronchoconstriction. Common side effect is peripheral oedema. INDAPAMIDE BISOPROLOL Commonly causes hyponatraemia. Used as an adjunct in heart failure, usually at , Contraindicated in asthma and COPD with bronchoconstriction. BENDROFLUMETHIAZIDE AMLIPINE 5 10 Common side effect is peripheral oedema.

14 METOLAZONE 5 on alternate days Metolazone is a potent diuretic and can cause profound prerenal renal dysfunction. For this reason low doses are given for hypertension treatment, often on alternate days. For resistant oedema higher doses of 80 (maximum) can be given, but this is a very high dose.