Potassium sparing diuretics should not be prescribed routinely but may be useful where hypokalaemia may be expected or where any degree of hypokalaemia could be hazardous (e.g. concomitant digoxin, arrhythmias).

Amiloride

• Tablets 5mg (£13.40 = 28 tablets)

Indications

• Potassium conservation when used as an adjunct to thiazide or loop diuretics

Dose

• Used alone, initially 10mg daily or 5mg twice daily, adjusted according to response; maximum 20mg daily
• With other diuretics, congestive heart failure and hypertension, initially 5–10mg daily; cirrhosis with ascites, initially 5mg daily

Aldosterone antagonists

Spironolactone

• Tablets 25mg, 50mg, 100mg (£3.83 = 100mg daily)

Indications

• Chronic heart failure
• Resistant hypertension (unlicensed indication)

Dose

• Moderate to severe heart failure (adjunct) initially 25mg once daily, increased according to response to maximum 50mg once daily
• Resistant hypertension (adjunct) 25mg once daily (unlicensed indication)

Notes

1. In severe heart failure, spironolactone added to other treatments in a low dose can reduce mortality and morbidity. Careful monitoring for hyperkalaemia and hypovolaemia is required especially for people taking other diuretics and/or ACE inhibitors.

Eplerenone

• Tablets 25mg, 50mg (£3.83 = 50mg daily)

Indications

• Heart failure developing 3-14 days post MI

Dose

• Start at 25mg daily and increase within 4 weeks according to serum potassium (see notes below)

Notes

1. Eplerenone has been shown to reduce mortality in patients developing heart failure post MI when initiated within 3-14 days. It may be initiated at a dose of 25mg provided serum potassium less than 5mmol/L and should be titrated to 50mg within 4 weeks unless serum potassium exceeds 5mmol/L. If the serum potassium exceeds 5.5mmol//L, the dose should be reduced or withheld (consult product literature).

Finerenone

• Tablets 10mg, 20mg (£36.68 = 20mg daily)

Indication

• Chronic kidney disease (stage 3 and stage 4 with albuminuria) associated with type 2 diabetes in line with NICE TA877 (see note 6)

Dose

• eGFR ≥25 to <60ml/min/1.73m²:
  • Starting dose 10mg once daily, increasing to 20mg once daily after 4 weeks according to serum K level (see note 1 for initiation).
  • Thereafter, dose adjustment and interruption according to serum K level (see note 2). Maximum dose: 20mg once daily.
  • Discontinue treatment in patients who progress to end-stage renal disease (≤15ml/min/1.73m²) due to limited clinical data
• eGFR <25ml/min/1.73m²: treatment should not be initiated due to limited clinical data
• Hepatic impairment: finerenone should not be initiated in severe hepatic impairment, a significant increase in exposure to finerenone is expected. No dose adjustment required in mild or moderate hepatic impairment.

​Notes​

1. Initiation:
   1. Specialist team:
      1. Specialist to start treatment with finerenone, prescribe and monitor until dose stabilised. Primary care to be asked to take on long-term prescribing and monitoring.
   2. Finerenone can be initiated if serum K <4.8mmol/l. Initiation may be considered if serum K 4.8 to 5.0mmol/L, with additional K monitoring in the first 4 weeks depending on patient characteristics and K level. Do not initiate treatment if K >5.0mmol/L.
   3. Measure serum K and eGFR 4 weeks after initiation. Refer to table below to determine continuation of treatment and daily dose.
2. Treatment continuation and monitoring:
   1. Measure serum K and eGFR 4 weeks after increase in dose or re-starting finerenone (see table below for dose adjustment and interruption of treatment).
   2. Measure serum K periodically as per stage of CKD (see NICE NG203 Frequency of monitoring)
   3. Additional monitoring of serum K is recommended with concomitant administration of certain drugs (see note 4) and may be required in moderate hepatic impairment due to an increase in exposure of finerenone.
   4. BP monitoring recommended with concomitant use of multiple other antihypertensive medicines.
3. Elderly: No dose adjustment is necessary in elderly patients.
4. Drug interactions: Finerenone is cleared almost exclusively via cytochrome P450 (CYP) (mainly CYP3A4 [90%]).
   1. Concomitant administration with strong CYP3A4 inhibitors is contraindicated and is not recommended with strong and moderate CYP34A inducers, potassium-sparing diuretics and other mineralocorticoid receptor antagonists.
   2. Additional monitoring of serum K should be considered with concomitant moderate or weak CYP3A4 inhibitors, potassium supplements, trimethoprim, or trimethoprim/sulfamethoxazole.
   3. Temporary discontinuation of finerenone may be necessary, when patients have to take trimethoprim, or trimethoprim/sulfamethoxazole.
   4. Refer to the BNF or the finerenone SmPC for advice on interactions.
5. Kerendia tablets may be crushed and mixed with water or soft foods, such as apple sauce, directly before oral use.
6. NICE TA877 (March 2023): Finerenone (Kerendia) ​is recommended​ as an option for treating stage 3 and 4 chronic kidney disease (with albuminuria, that is, an albumin to creatinine ratio that is persistently 3 mg/mmol or more) associated with type 2 diabetes in adults, only if:
   
   1. it is an add-on to optimised standard care; this should include, unless they are unsuitable, the highest tolerated licensed doses of:
      1. angiotensin-converting enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs) and 
      2. sodium–glucose cotransporter 2 (SGLT2) inhibitors and 
   2. the person has an estimated glomerular filtration rate (eGFR) of 25 ml/min/1.73 m² or more.

Finerenone doses during treatment continuation

* maintain 10 mg once daily, if eGFR has decreased >30% compared to the previous measurement