Clinical Guideline Bone chemistry management for pre-dialysis adult patients (CKD stage 3 5)

Transcription

1 Clinical Guideline Bone chemistry management for pre-dialysis adult patients (CKD stage 3 5) This guidance covers how to: Maintain serum phosphate as close to normal as possible ( mmol/L). 1 Maintain serum corrected calcium between 2.13 and 2.50mmol/L. 1 Maintain serum parathyroid hormone (PTH) within normal reference range ( pmol/L). 1 Restrict daily intake (from phosphate-binding medicines) of elemental calcium to no more than 1500mg for stable patients, unless in special circumstances. 2 General Information Patients will be referred by the nephrology team to a renal dietitian for advice on maintaining a lowphosphate diet (800 to 1000mg phosphorus per day). (N.B If patients are not eating well, dietary phosphate restrictions may be relaxed under dietetic supervision). Patients will be prescribed an appropriate dose of: A phosphate binding agent(s). Alfacalcitol/calcitriol The renal dietitian will advise patients on the timing and distribution of phosphate binders. This guideline applies to patients who have chronic kidney disease (CKD) stages 3 5 but do not yet require dialysis. It also applies to failed renal transplant patients who do not yet require dialysis. Blood Results 1. Corrected calcium The guidance relates to calcium levels corrected for serum albumin: Corrected calcium [mmol/l] = 0.02 x (40 serum albumin [g/l]) + serum calcium [mmol/l] Calcium should be checked during each clinic visit. If patient is hypercalcaemic (if nausea, vomiting or limb parasthesia occurs) or hypocalcaemic check calcium once a week until back within normal range If patient is started on alfacalcidol, or its dose is changed, check calcium after one week, then at least once a month for the first 3 months and during each clinic visit thereafter 2. Phosphate Phosphate should be checked during each clinic visit Refer to Chart 1 (p4) to determine whether treatment is necessary 3. Parathyroid hormone (PTH) PTH should be checked during each clinic visit Refer to Chart 2 (p5) to determine whether treatment is necessary 4. Aluminium Check yearly If patient are taking Alucaps, check during each clinic visit (no more frequently than every three months). If serum aluminium >1.5micromol/L, refer to a consultant nephrologist. Page 1 of 6

2 Phosphate-binding preparations (see Appendix 1 for cost comparisons) Trade name of phosphate binder Constituent and amount per tablet Amount of elemental calcium per tablet Administration method and timing in relation to meals Calcichew Calcium carbonate 1.25g 500 mg Chew or suck with meals PhosLo Calcium acetate 667mg 169mg Swallow whole with meals Phosex Calcium acetate 1000mg 250 mg Swallow whole with meals Alu-Caps Renagel Fosrenol Aluminium hydroxide 475mg Sevelamer hydrochloride 800mg Lanthanum carbonate 500mg, 750mg, 1000mg 0 Swallow whole with meals 0 Swallow whole with meals 0 Chew with, or immediately after, meals Aluminium hydroxide may be prescribed under the discretion of a clinician in resistant cases of hyperphosphataemia. Administration advice Phosphate binders should be taken at the appropriate time with relation to meals. Phosphate binders should not be taken within 2 hours of taking iron supplements. Phosphate binders should not be taken without food. Phosphate binders must be taken with phosphate-containing food or snacks whilst patient is on dialysis Quantity of phosphate binders taken with each meal should be determined according to the size of meal. Oral calcium may interfere with the absorption of biphosphonates, ciprofloxacin, levothyroxine, and tetracycline. These agents should be taken at least two hours before or four to six hours after calcium. Aluminium hydroxide may reduce the absorption of antibiotics (e.g cefaclor, quinolones, tetracyclines). Aluminium hydroxide is contraindicated in patients with hypophosphataemia or porphyria. Accumulation in renal failure has been linked with neurotoxicity, osteomalacia and a reduced response to erythropoietin. Supply of phosphate binders and/or alfacalcidol/calcitriol Phosphate binders and alfacalcidol are supplied on prescription by GPs. If any dose or type of treatment is altered, started or stopped, a standard letter detailing the change will be completed by the renal dietitian, renal pharmacist or renal specialist nurse (using the CyberRen system), signed by a consultant nephrologist or a non-medical prescriber, and sent to the GP. A second copy of this letter should be produced and filed in the patients medical notes. A standard letter will also be sent (by the renal dietician, renal pharmacist or renal specialist nurse) to the patient with details of their new/amended medication and to remind them to collect their new prescription from their GP. Page 2 of 6

3 Chart 1: Hyperphosphataemia pathway in pre-dialysis renal patients with CKD stages 3 5 (secondary care use) Serum phosphate >1.5mmol/L Refer to dietician for dietary phosphate restriction. Corrected calcium* <2.3mmol/L Corrected calcium* 2.3mmol/L Calcium carbonate 1.25g (Calcichew ) three tablets/day with meals Or Calcium acetate 667mg (PhosLo ) titrate up to nine capsules/day with meals Or Calcium acetate 1g (Phosex ) titrate up to six tablets/day with meals. Check bloods at next clinic appointment. Phosphate >1.5mmol/L and corrected calcium 2.5mmol/L Check compliance with medication and educate patient Start sevelamer hydrochloride (Renagel ) 800mg three tablets/day with meals. Titrate in increments of three tablets/day with meals until phosphate 1.5mmol/L or patient taking 9 sevelamer tablets per day. Consider stopping calcium-based phosphate binder If corrected calcium* <2.1mmol/L refer to consultant If phosphate >1.5mmol/l and patient taking 9 sevelamer tablets/day or not tolerating sevelamer Continue to monitor. Phosphate binders may need to be reduced if phosphate falls <0.8mmol/L. If phosphate becomes >1.5mmol/L No Phosphate >1.5mmol/L? Yes Check compliance with medication and educate patient. Refer to consultant if phosphate remains >1.5mmol/L. Check compliance with medication and educate patient. Stop sevelamer hydrochloride. Start lanthanum carbonate (Fosrenol ) 500mg three tablets/day with meals. Titrate as necessary to 750mg three tablets/day with meals and then 1000mg three tablets/day with meals until phosphate 1.5mmol/L or patient taking 3000mg/day. In some patients it may be necessary to start at a higher dose of lanthanum per day. Notes: Calcium and phosphate are routinely monitored during clinic visits *Corrected calcium (mmol/l) = 0.02(40-albumin) + serum calcium Page 3 of 6

4 Chart 2: Alfacalcidol Pathway PTH >6.9pmol/L Start alfacalcidol 250nanograms orally once daily Monitor PTH every clinic visit PTH >6.9 pmol/l PTH 6.9 pmol/l Increase alfacalcidol by 250 nanograms orally once daily providing corrected Ca is <2.5mmol/L Up to a maximum of 1microgram daily Continue alfacalcidol at current dose If PTH remains >6.9pmol/L Or if Ca >2.5mmol/L Refer to consultant for alfacalcidol dose advice Page 4 of 6

5 Chart 3: Hypercalcaemia pathway in patients with CKD stages 3 5 (secondary care use) Corrected calcium* >2.50mmol/L Check patient is not taking any over-thecounter calcium- containing medicines such as Rennie, Tums, etc Stop calcium-based phosphate binders and convert to non-calcium based binders (see table on page 2) *Corrected calcium (mmol/l) = 0.02(40-albumin) + serum calcium If corrected calcium* returns to <2.50mmol/L continue with current therapy and re-check as normal next clinic visit Recheck calcium in a month If corrected calcium* >2.50mmol/L. If prescribed, consider changing alfacalcidol to pulsed weekly dose. Recheck calcium in one month If corrected calcium* >2.50mmol/L. Reduce/stop alfacalcidol, if prescribed Recheck calcium in one month Seek medical attention if corrected calcium* remains >2.50mmol/L Page 5 of 6

6 Appendix 1: Cost Comparisons - Phosphate Binders Trade name of phosphate binder Constituent and amount per tablet Maximum maintenance dose* Cost per 28 days** Cost per original pack** Calcichew Phosex PhosLo *** Alu-Caps Renagel Fosrenol Calcium carbonate 1.25g Calcium acetate 1000mg Calcium acetate 667mg Aluminium hydroxide 475mg Sevelamer hydrochloride 800mg Lanthanum carbonate 500mg 750mg 1000mg 3 tablets/day tablets 6 tablets/day tablets 9 capsules/day Capsules 9 capsules/day Capsules 9 tablets/day Tablets 3000mg/day tablets *Maximum maintenance dose as per Wirral and Chester Nephrology Units Clinical Guidance for the Management of Bone Chemistry. **Prices based on current costing including VAT for January *** The Scottish Medicines Consortium (SMC) has accepted calcium acetate (PhosLo ) for use in NHS Scotland for prevention/treatment of hyperphosphataemia in patients with advanced renal failure on dialysis 3. References 1. Steddon S, Sharples E. CKD-Mineral and Bone Disorders. Available at: (accessed 26 April 2011) 2. National Kidney Foundation. K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease in CKD. American Journal of Kidney Disease 2003;42:suppl Scottish Medicines Consortium. Calcium acetate (Phoslo): advice. Available at: (accessed 26 April 2011). Page 6 of 6