Dialysis and Drugs

7/29/2019 Dialysis and Drugs

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Dialysis and Drugs

Carmela D. Barcelona, RPh

Department of Pharmacy

UP College of Pharmacy



Learning Objectives

• At the end of the lecture, the student shall be able to:

– Define dialysis

– Enumerate indications for dialysis

– Identify goals of dialysis

– Differentiate types of dialysis

– Identify common complications of dialysis and ways tomanage them

– Perform dose adjustments for dialyzable drugs based on

creatinine clearance

– Make recommendations for patients using dialyzablemedications



Renal Replacement Therapy (RRT)

• Indication for end-stage kidney disease (ESKD)

• Modalities: dialysis (HD, PD) and kidney

transplantation



Indications for Dialysis

• GFR < 30 mL/min/1.73 m2 (stage 4 CKD); < 15mL/min/1.73 m2

• Progression to ESKD is inevitable

– To allow time to educate patient and family ontreatment modalities and establish appropriateaccess for the modality of choice

• Should be done at a point when the patient isready to undergo treatment, rather than whenthe patient is in emergent need of dialysis



Indications for Dialysis

SYMPTOMS

• Persistent anorexia

• Nausea

• Vomiting

• Fatigue

• Pruritus

OTHER CRITERIA

• Declining nutritional status

• Declining serum albumin

levels• Uncontrolled hypertension

• Volume overload

– Chronic heart failure

– Electrolyte abnormalities(hyperkalemia)

• BUN and SCr levels



Goals of Dialysis

• Remove toxic metabolites to decrease uremic

symptoms

• Correct electrolyte abnormalities

• Restore acid-base status

• Maintain volume status

•

Improve QOL• Decrease morbidity and mortality associated

with ESKD



Principles of Hemodialysis (HD)

• Involves exposure of blood to asemipermeable membrane (?) vs. which aphysiologic solution (?) is flowing

• Dialyzer: capillary fibers inc SA for bloodexposure for more efficient removal of substances

•

Dialysate: purified water + electrolytes;nonsterile

• Diffusion, ultrafiltration, convection



Common Complications of HD

• Hypotension

• Muscle cramping

•

Thrombosis• Infection



Hypotension

• Most common (~ 10-30% of dialysis sessions upto 50%)

• Symptomatic sudden drop of > 30 mmHg in meanarterial or SBP or SBP drop to < 90 mmHg duringHD

• 10 cause: fluid removal from the bloodstream – Antihypertensive meds prior to HD

– Target “dry” weight too low

– Low dialysate Ca or Na

– High dialysate temperature

– Ingesting meals prior to HD



Hypotension

RISK FACTORS

• Elderly age

• Diabetes

• Autonomic neuropathy

• Uremia

• Cardiac disease

SYMPTOMS

• Dizziness

• Nausea

• Vomiting

• Sweating

• Chest pain



Treatment of Hypotension

PHARMACOLOGIC:

to restore intravascular volume

• Normal saline (100 – 200

mL)

• Hypertonic saline (23.4%,10 – 20 mL)

• Mannitol (12.5 g)

NONPHARMACOLOGIC

• Trendelenburg position

• Decreasing ultrafiltration

rate



Muscle Cramping

• Up to 20% of HD sessions

• Cause related to ultrafiltration hypoperfusionof muscles

– Hypotension – Electrolyte and acid-base imbalances

• Rx: 400 IU vitamin E daily; oxazepam, prazosin

• nonRx: decreasing ultrafiltration rate, accuratedetermination of dry weight



Thrombosis

• Most common in patients with venous

catheter access for HD; common cause of

catheter failure

• Rx: local administration of thrombolytics (e.g.,

2 mg alteplase, 0.5 unit reteplase per port)

• nonRx: saline flushes or balloon angioplasty;

catheter replacement



Infection

• Important cause of morbidity and mortality in HDpatients high risk for bacteremia

• Related to organisms found on the skin (e.g., S.epidermidis and S. aureus)

• Venous catheters most commonly infected• Blood cultures for febrile patients

• nonRx: sterile technique, proper disinfection,minimizing use and duration of venous cath for HD

access• Rx: antimicrobial based on culture; mupirocin at exit

site, PVI ointment



Peritoneal Dialysis (PD)

• Same principles as HD

– Semipermeable membrane = peritoneal membrane;

sterile dialysate instilled into peritoneal cavity

• Mesothelial cells lined with microvilli increase SA

– BVs of abdominal organs, muscle and mesentery =

blood component

– Gaps between cells allow entry of large solutes into

bloodstream

– Interstitium and endothelial cells of BVs provide

resistance to limit solute size removed from blood



Peritoneal Dialysis

• Diffusion: most important component of solutetransport

• Polymeric glucose derivatives (e.g., icodextrin):create osmotic gradient for ultrafiltration andconvection

• Dwell time of dialysate – Drained and replaced with fresh dialysate

– Continuous nature• Mimics endogenous kidney function by dec fluctuations in

serum conc of waste products

• Constant rate of water removal: dec fluctuations inintravascular fluid balancemore hemodynamic stability



Types of PD

• Continuous ambulatory peritoneal dialysis

(CAPD)

• Automated peritoneal dialysis (APD)

• Continuous cycling PD (CCPD)

• Nightly intermittent PD (NIPD)

•

Nocturnal tidal PD (NTPD)



Complications of PD

• Mechanical problems related to PD catheter – Kinking, migration, adherence to peritoneal tissue,

excessive movement at exit site

• Metabolic problems associated with componentsof dialysate – Exacerbation of DM from glucose load

– Fluid overload ( exacerbation of chronic HF, edema, pulmo congestion)

– Electrolyte abnormalities – Malnutrition (albumin and AA loss, muscle wasting,

increased adipose tissue, fibrin formation in dialysate)



Complications of PD

• Peritoneal damage

– Alterations in permeability, sclerosis

• Infections

– Peritonitis, catheter-related infections (exit-siteinfections, tunnel infections)

• Pain

– Impringement of catheter tip on visceral organs

– Instillation pain (rapid flow of dialysate, acidic pH of dialysate, chemical irritation from dialysate additives,low dialysate temperature)



RENAL FUNCTION ESTIMATION INADULT PATIENTS

Estimated GFR (eGFR) and Creatinine clearance (CrCl)



Cockcroft - Gault Equation

• M: CrCl = (140 – age in yrs) x BW in kg

72 x SCr in mg/dL

• F: CrCl = 0.85 x CrCl using formula in males

• mL/min



Jelliffe Equation

• M: CrCl = 98 – 0.8 x (age in yrs – 20)

SCr in mg/dL

• F: CrCl = 0.9 x CrCl using formula in males

• mL/min/1.73 m2



Four-variable Modification of Diet in

Renal Disease (MDRD)

• eGFR = 175 X (Creatinine)-1.154 X (Age)-0.203 X

(Gender) X (Race)

where:

– eGFR = estimated GFR in mL/minute/1.73 m2

– Creatinine in mg/dL

– Age in years

– Gender: Females = 0.742; Males = 1

– Race: Black = 1.212; White or other = 1



Six-variable MDRD or Extended

MDRD

• eGFR = 161.5 X (Creatinine)-0.999 X (Age)-0.176 X(SUN)-0.170 X (Albumin)0.318 X (Gender) X (Race)

where:

– eGFR = estimated GFR in mL/minute/1.73 m2

– Creatinine in mg/dL

– Age in years

– SUN = Serum Urea Nitrogen in mg/dL

–

Albumin = Serum Albumin in g/dL – Gender: Females = 0.762; Males = 1

– Race: Black = 1.18; White or other = 1



Sample Case

• A 75 y/o patient weighing 132 lbs wasdiagnosed with nosocomial pneumonia andhis AP planned to start him on Meropenem.

The clinical pharmacist was asked for thedose. What will be your recommendation?

•

Ask for SCr.• (normal SCr) Start patient on Meropenem 1g

IV every 8 hours.



Sample Case

• On day 5 of admission, the patient’s SCr was2.3 mg/dL. What will be yourrecommendation on the antibiotic dose?

• CrCl = (140 – 75 yrs) x 132 lbs (1 kg/2.2 lbs) = 23.55 mL/min

72 x 2.3 mg/dL

• Administer ½ recommended dose based onindication every 12 hoursMeropenem 500mg IV every 12 hours



Sample Case

• Based on the new dosing interval, when willbe the next dose of Meropenem if last dosewas given at 6AM? How will you instruct the

nurse?

• Next dose will be Meropenem 500 mg IV at 6

PM of same day.• Return Meropenem 1 g vials and request for

500 mg vials.



Sample Case

• The patient’s SCr levels continued to increase in

the succeeding days and was assessed for

hemodialysis. What will be your recommendation

for his antibiotic? How will you instruct the nursein administering the drug?

•Administer Meropenem 500 mg IV every 24hours.

• Administer drug post-dialysis since it is dialyzable.



Sample Case

• HD was ordered to run for 6 hours starting at

11 AM. 6AM dose was administered by the

nurse. When will be the next dose?

• Administer Meropenem 500 mg IV at 6 AM

the following day.



THANK YOU FOR YOUR KINDATTENTION!

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Dialysis and Drugs

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