2.5.5 Drugs affecting the renin-angiotensin system

MHRA Drug Safety Update, June 2014: Combination use of medicines from different classes of renin-angiotensin system blocking agents is associated with an increased risk of hyperkalaemia, hypotension, and impaired renal function and is therefore not recommended.

  • Combination use of medicines from two classes of RAS blocking agents (ACE inhibitor (ACEi), Angiotensin Receptor Blocker (ARB) or direct renin inhibitors (aliskiren)) is not recommended.
  • The combination of an ACEi and an ARB is not recommended for the management of primary hypertension.
  • Prescribers are advised not to give patients with diabetic nephropathy an ACEi with an ARB since they are particularly prone to developing hyperkalaemia.
  • The combination of aliskiren with an ACEi or ARB is contraindicated in patients with kidney impairment (estimated glomerular filtration rate [eGFR] < 60 mL/minute/1.73 m2) or diabetes.
  • Combination therapy with ACEi and ARBs may be initiated only by specialists for patients with resistant proteinuria which is unresponsive to either medication alone.

Patients with heart failure:

  • The benefits of combination use may outweigh the risks in a selected group of people with heart failure for whom other treatments are unsuitable. Some patients with heart failure may have a medical need for treatment with an ACEi and an ARB. Candesartan and valsartan are licensed as add-on therapy to ACEi for people with symptomatic heart failure who require such a combination despite optimal therapy. Specialist guidance should be sought.
  • The triple combination of an ACEi, ARB, and a mineralocorticoid receptor antagonist or other potassium-sparing diuretic is not recommended.

If combination use is considered absolutely necessary, it must be carried out under specialist supervision and with close monitoring of blood pressure, renal function, and electrolyte levels (particularly potassium). Consider monitoring patients when combination use is started and on a monthly basis thereafter, and also after changing dose and during intercurrent illness.

Monitoring of drugs acting on the renin-angiotensin system:

  • Measure serum potassium concentrations and eGFR before starting ACEi, ARBs and direct renin inhibitors. Repeat these measurements between 1 and 2 weeks after starting, after each dose increase, and regularly during intercurrent illness or if concomitant drug treatment is modified; thereafter renal function should be monitored regularly (e.g. annually).
  • Healthcare Commission audit standards advise 6 monthly monitoring of renal function in patients with heart failure. Consider monitoring these parameters monthly in patients taking a combination of medication acting on the renin-angiotensin system.
  • Following introduction or a dose increase, if either the eGFR decrease from pretreatment baseline is less than 25% or the serum creatinine increase from baseline is less than 30% do not modify the dose; repeat the test in 1–2 weeks. If the eGFR change is 25% or more, or the change in serum creatinine is 30% or more stop drug, and investigate cause of deterioration in renal function, such as volume depletion or concurrent medication (for example, NSAIDs). If no explanation, consider investigation for renal artery stenosis. Do not discontinue for lesser changes in eGFR/creatinine, some change is expected. If no cause for the deterioration in renal function is found, stop the medication or reduce the dose to a previously tolerated lower dose, and add an alternative antihypertensive medication if required.
  • Do not routinely offer a drug that blocks or inhibits the renin–angiotensin to people with CKD if their pre-treatment serum potassium concentration is greater than 5.0 mmol/litre.
  • Concurrent prescription of drugs known to promote hyperkalaemia (e.g. NSAIDs or potassium sparing diuretics) is not a contraindication to the use of these agents, but be aware that more frequent monitoring of serum potassium concentration may be required. Use the lowest effective dose of spironolactone and ACEi or ARB if co-administration is considered essential.
  • If serum potassium concentration increases to 6.0 mmol/litre or more, stop drugs known to promote hyperkalaemia and check diet as a cause for raised potassium (e.g. 'LoSalt' intake). If hyperkalaemia persists the ACEi or ARB should be stopped. Modest stable hyperkalaemia may be preferable to discontinuing a valuable therapy.

All patients who have indications for ACEi or ARBs are at higher risk of acute kidney injury (AKI), therefore consideration should be given to stopping these drugs temporarily during an acute illness that increases the risk of AKI (for example, diarrhoea, vomiting and other conditions leading to dehydration or shock).

2.5.5.1 Angiotensin-converting enzyme inhibitors

Doses of ACEi should be titrated up until target doses are reached. In heart failure it is important that ACEi are titrated up to their target dose (or maximum tolerated), as advised by NICE.

Patients discharged from hospital following an acute coronary syndrome, post MI have usually been started on ACEi and beta-blockers, however the doses are usually suboptimal and need up-titrating. Following an infarct with significant damage to the left ventricle it is important that the ACEi is up-titrated first. Doses can be increased every 2 weeks in accordance with the BNF dosing regimen. The beta-blocker needs up-titrating with similar time intervals. Up-titrate agents one at a time.

Profound first-dose hypotension may occur when ACEi are introduced to patients with heart failure who are already taking a high dose of a loop diuretic (e.g. furosemide 80 mg daily or more). Temporary withdrawal of the loop diuretic reduces the risk, but may cause severe rebound pulmonary oedema. Therefore, for patients on high doses of loop diuretics, the ACEi may need to be initiated under specialist supervision. An ACEi can be initiated in the community in patients who are receiving a low dose of a diuretic or who are not otherwise at risk of serious hypotension; nevertheless, care is required and a very low dose of the ACEi is given initially.

ACEi should be initiated under specialist supervision and with careful clinical monitoring in those with severe heart failure or in those:

  • receiving multiple or high-dose diuretic therapy (e.g. more than 80 mg of furosemide daily or its equivalent);
  • receiving concomitant ARB or aliskiren;
  • with hypovolaemia;
  • with hyponatraemia (plasma-sodium concentration below 130 mmol/litre);
  • with hypotension (systolic blood pressure below 90 mmHg);
  • with unstable heart failure;
  • receiving high-dose vasodilator therapy;
  • known renovascular disease.
Lisinopril
  • Tablets 2.5mg, 5mg, 10mg, 20mg (£0.74 = 5mg daily)

Indications

Dose

  • Hypertension:
    • initially 10mg once daily;
    • if used in addition to diuretic or in cardiac decompensation or in volume depletion, initially 2.5–5mg once daily;
    • usual maintenance dose 20mg once daily; maximum 80mg once daily
  • Heart failure (adjunct), initially 2.5mg once daily under close medical supervision; increased in steps no greater than 10mg at intervals of at least 2 weeks up to maximum 35mg once daily if tolerated
  • Renal complications of diabetes mellitus, initially 2.5–5mg once daily adjusted according to response; usual dose range 10–20mg once daily
Ramipril
  • Capsules 1.25mg, 2.5mg, 5mg,10mg (£1.26 = 5mg daily)

Indications

Dose

  • Hypertension, initially 1.25–2.5mg once daily, increased at intervals of 2–4 weeks to maximum 10 mg once daily; if used in addition to diuretic
  • Heart failure (adjunct), initially 1.25mg once daily under close medical supervision, increased gradually at intervals of 1–2 weeks to maximum 10mg daily if tolerated (preferably taken in 2 divided doses)
  • Prophylaxis after myocardial infarction (started at least 48 hours after infarction), initially 2.5mg twice daily, increased after 3 days to 5mg twice daily
  • Prophylaxis of cardiovascular events, initially 2.5mg once daily, increased after 1–2 weeks to 5mg once daily, then increased after a further 2–3 weeks to 10mg once daily
  • Nephropathy, initially 1.25mg once daily, increased after 2 weeks to 2.5mg once daily, then increased after a further 2 weeks to 5mg once daily if tolerated

Notes

  1. Ramipril is the preferred post-MI ACE inhibitor
  2. Ramipril should only be prescribed as the capsules as these are less expensive than ramipril tablets
  3. Ramipril is included as it is excreted by dual pathways
Perindopril erbumine
  • Tablets 2mg, 4mg, 8mg (£1.21 = 4mg daily)

Indications

Dose

  • Hypertension
    • initially 4mg once daily in the morning for 1 month, subsequently adjusted according to response;
    • if used in addition to diuretic, in elderly, in renal impairment, in cardiac decompensation, or in volume depletion, initially 2mg once daily; maximum 8mg daily
  • Heart failure (adjunct), initially 2mg once daily in the morning under close medical supervision, increased after at least 2 weeks to maximum 4mg once daily if tolerated
  • Following myocardial infarction or revascularisation
    • initially 4mg once daily in the morning increased after 2 weeks to 8mg once daily if tolerated;
    • elderly 2mg once daily for 1 week, then 4mg once daily for 1 week, thereafter increased to 8mg once daily if tolerated

Notes

  1. Perindopril should be prescribed generically as listed. Coversyl® Arginine is not dose equivalent and is not included in the formulary.
Captopril
  • Tablets 12.5mg, 25mg, 50mg
  • Oral Solution 5mg/ml

Indications

  • Captopril is included as a hospital only drug for initiation of ACE inhibitors and for use in specialist areas.

Notes

  1. Patients stabilised on captopril do not need to be changed to a formulary ACE inhibitor.

2.5.5.2 Angiotensin-II receptor antagonists

Angiotensin-II receptor antagonists (ARBs) can be used for those patients who suffer from unacceptable side effects when using ACEi. ARBs have many similar properties to ACEi. However, unlike ACEi, are less likely to cause the persistent dry cough which can complicate ACEi therapy. They are therefore a useful alternative for patients who have to discontinue an ACEi because of persistent cough. Note that cough is common in patients with chronic heart failure, many of whom have smoking-related lung disease. Cough is also a symptom of pulmonary oedema which should be excluded when a new or worsening cough develops. Care should therefore be taken when attributing 'worsening cough' as a side effect of ACE inhibitor treatment.

Candesartan
  • Tablets 2mg, 4mg, 8mg, 16mg, 32mg (£1.07 = 8mg daily)

Indications

Dose

  • Hypertension, initially 8mg (intravascular volume depletion 4mg) once daily, increased if necessary at intervals of 4 weeks to maximum 32mg once daily; usual maintenance dose 8mg once daily
  • Heart failure, initially 4mg once daily, increased at intervals of at least 2 weeks to 'target' dose of 32mg once daily or to maximum tolerated dose
Losartan
  • Tablets 12.5mg, 25mg, 50mg, 100mg (£0.87 = 50mg)
  • Oral suspension 2.5mg/5mL (£53.68 = 200ml)

Indications

  • Hypertension
  • Renal protection in type 2 diabetic patients with nephropathy (microalbuminuria).

Dose

  • Usually 50mg once daily (intravascular volume depletion, initially 25mg once daily); if necessary increased after several weeks to 100mg once daily; over 75 years of age initially 25mg daily
Irbesartan
  • Tablets 75mg, 150mg, 300mg (£1.77 = 300mg daily)

Indications

Dose

  • Initially 150mg once daily increased over several weeks to 300mg once daily if tolerated
Valsartan
  • Capsules 40mg, 80mg, 160mg (£1.41 = 160mg twice daily)

Indications

  • Post myocardial infarction

Dose

  • Initially 20mg twice daily increased over several weeks to 160mg twice daily if tolerated
Sacubitril/ valsartan
  • Tablets sacubitril 24mg/ valsartan 26mg (£91.56)
  • Tablets sacubitril 49mg/ valsartan 51mg (£91.56)
  • Tablets sacubitril 97mg/ valsartan 103mg (£91.56)

Indications

  • Sacubitril valsartan is recommended in accordance with NICE TA388 (April 2016) as an option for treating symptomatic chronic heart failure with reduced ejection fraction, only in people:
    • with New York Heart Association (NYHA) class II to IV symptoms and
    • with a left ventricular ejection fraction of 35% or less and
    • who are already taking a stable dose of angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor-blockers (ARBs)
  • Prior treatment with an ACE inhibitor or ARB is a pre-requisite in accordance with NICE TA388, however treatment must be stopped prior to initiation of sacubitril valsartan.

Dose

  • The initial dose is one tablet of 49mg/51mg twice daily, except in the situations described below. The dose should be doubled at 2-4 weeks to the target dose of one tablet of 97mg/103mg twice daily, as tolerated by the patient.
  • A lower starting dose of 24mg/26mg may be required for patients who were taking a low dose of ACE inhibitor or ARB, patients with low systolic blood pressure, or renal impairment (see manufacturer's information for further details)
  • Treatment should not be initiated in patients with serum potassium level >5.4mmol/l or with SBP <100 mmHg

Notes

  1. Treatment with sacubitril valsartan should be initiated by a heart failure Consultant. Following dose titration and once the patient is stabilised on treatment by the specialist heart failure team, ongoing management and monitoring of the patient may be performed in primary care. Initial clinical assessment, monitoring and prescribing will remain the responsibility of the specialist heart failure team for at least the first three months
  2. Sacubitril valsartan should not be co-administered with an ACE inhibitor or and ARB. Due to the potential risk of angioedema when used concomitantly with an ACE inhibitor, sacubitril valsartan must not be started for at least 48 hours after discontinuing ACE inhibitor therapy. A washout period is not needed if switching from an ARB to sacubitril valsartan
  3. To avoid accidental prescribing of concomitant ACEi or ARB it is recommended that sacubitril valsartan is prescribed using the generic name
  4. Following stabilisation on a maximum tolerated dose, patients should be monitored in line with the NICE clinical guideline on chronic heart failure management.

2.5.5.3 Renin inhibitors

Aliskiren
  • Tablets 150mg, 300mg (£28.51 = 150mg daily)

Indications

  • Hypertension in combination with other antihypertensives for patients who remain hypertensive despite maximal therapy with other agents.

Dose

  • 150mg once daily, increased if necessary to 300mg once daily

Notes

  1. Consultant initiated
  2. The combination of aliskiren with ACE inhibitors or ARBs has been associated with serious adverse cardiovascular and renal outcomes. This combination is now contraindicated in;
    1. Diabetic patients (type 1 or type 2)
    2. Non-diabetic patients with and eGFR less than 60mL/min per 1.73m2
  3. In all other patient groups, aliskiren in combination with an ACE inhibitor or an ARB is not recommended.
  4. Any use of aliskiren (either as monotherapy or in combination with other medicines) is no longer recommended in any patient with severe renal impairment: eGFR less than 30mL/min/1.73m2.
  5. Please refer to MHRA Drug Safety Update (March 2012)

 

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