R&U Systems 3

Chronic Renal Failure: Vitamin D Analogs: calcitriol

Vitamin D Analogs

Prototypes: calcitriol (Rocaltrol)

Indications for use

• Hypoparathyroidism and management of hypocalcemia in patients undergoing chronic renal dialysis

Mechanism of action

• Binds to vitamin D receptors in the kidneys, parathyroid, intestines, and bones to raise serum calcium by enhancing intestinal absorption, renal reabsorption, and release from bone.

Adverse Drug Reactions

• Hypercalcemia: overshooting

Interventions/Nursing Actions

• Monitor Ca+ levels

Client Instructions

• Notify MD for any fast or Irregular heartbeat

• Confusion, increased thirst,

• Muscle or joint pain (may indicate Ca+ too high)

Contraindications

• Hypercalcemia

• Use caution with calcium supplements

Drug Interactions

• Corticosteroids, ketoconazole, digoxin, Phosphate binding agents, thiazide diuretics

Precautions

• pregnant/breastfeeding

• know how to educate patient

Renal Diet

• Limit proteins to high biologic value proteins.

• May need a fluid restriction as well

Chronic Renal Failure: Calcium Free Phosphate Binders: sevelamer hydrochloride

Calcium Free Phosphate Binders

Prototypes: sevelamer hydrochloride (Renvela)

Indications for use

• Hyperphosphatemia in end-stage renal disease

Mechanism of action

• Binds to phosphate in the gut and reduces it’s absorption

Adverse Drug Reactions

• GI intolerance, N/V/D, Dyspepsia, abd pain, nasopharyngitis, Limb pain, pruritus, arthralgia, and bronchitis

Interventions/Nursing Actions

• Do not crush

• Monitor bicarbonate, calcium, Phosphorus, parathyroid hormone, and chloride labs

Client Instructions

• Take with EVERY meals (~4x a day). Bind up phosphate while in GI tract before it gets absorbed.

• Do not crush or separate

Contraindications

• Presence of hypersensitivity

• Bowel obstruction

Drug Interactions

• Administer separate from other medication due to risk for decreased bioavailability

Precautions

• GI disorders such as UC

Stages of Chronic Kidney Disease

Dialysis

DIALYSIS = USUALLY WHEN GFR IS 15% OR LESS + S/S

Peritoneal dialysis

• hyperosmolar dialysate with dextrose & sodium

• reducing workload going to kidneys

Renal Dosing Across the lifespan: KID SAFE

Why it matters

• Kidneys remove many drugs from the body

• Impaired kidney function → drug build-up → toxicity

• Dosing must be adjusted to: patient’s age, renal function, clinical condition

How do we keep patients SAFE?

• Size dose to kidney function + age (pharmacy and provider will do this, but you need to report the information in front of you).

• Age extremes (neonates/elderly) = most risk.

• Follow levels + labs.

• Evaluate + be ready to adjust often

Neonates and Infants

• Kidneys immature at birth → ↓ clearance

• Drug half-life prolonged

• Require smaller doses or longer intervals (e.g., antibiotics)

• By ~1 year, renal function approaches adult levels

Children

• After infancy, renal clearance may be faster than adults

• Often require weight-based or body surface area dosing

• Careful monitoring essential

Adults

• Typically stable renal function if healthy

• Adjust dosing if kidney disease or acute illness (e.g., dehydration, sepsis)

Older Adults

• Normal aging → ↓ GFR and renal blood flow

• BEERS Criteria*

• “Normal” creatinine can be misleading (low muscle mass)

• Higher risk of accumulation (digoxin, aminoglycosides, lithium)

• Start low, go slow

Case Study

1) Renal Status: Based on the GFR of 38 mL/min, what stage of Chronic Kidney disease is the patient in?

• The patient is at stage 3B of Chronic Kidney Disease

2) BEERS Criteria ID: Identify the one medication on his list that is considered a Potentially Inappropriate Medication (PIM) for the elderly according to the BEERS criteria. What is the specific class of this drug, and why is it flagged (i.e., what risk does it pose)?

• Digoxin

3) What is the primary risk associated with this PIM in the elderly?

• The primary risk associated with this PIM is toxicity.

4) Considering Mr. Franklin's GFR of 38 mL/min, which renally-cleared medication should have its dose immediately reduced to prevent accumulation and toxicity?

• digoxin

5) What is the most critical pre-administration lab value a nurse must check before giving a renally-cleared drug like Digoxin or Allopurinol?

• Glomerular Filtration rate