Who are we? Drug dosing in special patient populations. Zamzam Ahmed, London United Kingdom Yolande Hanssens, Doha - Qatar

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1 Drug dosing in special patient populations Zamzam Ahmed, London United Kingdom Yolande Hanssens, Doha - Qatar ESCP Prague 16 October 2013 Who are we? yhanssens@hmc.org.qa y_hanssens@hotmail.com zamzam.ahmed.11@ucl.ac.uk zamzamahmed@gmailmail.com

2 3 Objectives To appreciate different patient populations and their very specific medication needs. To get an insight in specific references and dosing tools for these selected patients. To become familiar with information sources providing relevant details about drug dosing in special patient populations.

3 Outline of this session Introduction and definitions Practical clinical guidance, sources of information Case studies in small groups Feedback from the groups Conclusion & take home messages 10 min 15 min 60 min 20 min 10 min Medication One size fits all? 6

4 Medication Goldilocks window 8

5 Factors causing variation of drug blood levels Personalised medicine The right drug To the right patient For the right disease At the right time With the right dosage Using the right dosage form Based on the right information 10

6 Outline of this session Introduction and definitions Practical clinical guidance, sources of information Case studies in small groups Feedback from the groups Conclusion & take home messages 10 min 15 min 60 min 20 min 10 min This WS will focus on Obese Renal patients Geriatric

7 Obesity Pharmacokinetic parameters Principles to keep in mind when dosing obese patients 13 ABW, IBW, or Adjusted BW? Obesity Dosing principles 14

8 Obesity Useful References Pai MP, Bearden DT. Antimicrobial dosing considerations in obese adult patients. Pharmacotherapy. 2007;27(8): Myzienski AE, Lutz MF, Smythe MA. Unfractionated heparin dosing for venous thromboembolism in morbidly obese patients: case report and review of the literature. Pharmacotherapy. 2010;30(3):324. Erstad BL. Dosing of medications in morbidly obese patients in the intensive care unit setting. Intensive Care Med. 2004;30(1): Obesity More References Dosing.aspx#Devine

9 Obesity More References 1 page summary 17 Renal Disease Acute Kidney Injury (AKI) Chronic Kidney Disease/Injury (CKD/CKI) Renal Replacement Therapy (RRT) 18

10 Renal Disease Assessment of renal function: Serum creatinine (Sr Cr) Cockcroft and Gault (CG) equation The Modification of Diet in Renal Disease (MDRD) study equation The CKD-Epidemiology Collaboration (CKD-EPI) equation 19 Renal Disease Drug Dosing Considerations PK/PD Goals of therapy Assessment of patients General principles 20

11 Renal Disease Useful References 814 pages as interactive PDF free online 199/name/Renal+Drug+Handbook.pdf 21 Renal Disease Useful references 814 pages as interactive PDF free online 199/name/Renal+Drug+Handbook.pdf 22

12 Renal Disease Useful references Renal Disease Useful references

13 Geriatric Patients Age group classifications Pharmacokinetics Pharmacodynamics 25 Geriatric Patients Other considerations ADR Compliance Poly-pharmacy 26

14 Geriatric Patients General principles Beers & STOPP START Criteria 27 Geriatric Patients General principles STOPP START Criteria 28

15 Geriatrics - Resources Comparison with Other Related Books or Products: This annually updated handbook is unique in its focus on older adults. Reviewer s Summary: Provides a concise, practical, and easy-touse handbook that can provide dosing information quickly in the clinical setting. This handbook will be invaluable to all health professionals who prescribe and monitor medications in a practice with a significant geriatric population. 29 Geriatrics - Resources 30

16 Outline of this session Introduction and definitions Practical clinical guidance, sources of information Case studies in small groups Feedback from the groups Conclusion & take home messages 10 min 15 min 60 min 20 min 10 min Clinical Cases Your chance to work 32

17 Clinical Cases Your chance to work Patrick Hart, 50 years old, lives with his wife above the shop where he works part-time. He spends most evenings in; watching TV or he joins his friends in the pub for a few drinks. He thinks he drinks approximately 30 alcohol units per week. Mr. Hart has been struggling with obesity for many years and all his efforts to lose weigh have failed. He weighs 130 kg and his BMI is 50. He says he eats unhealthy food also admits to not doing any activities. He smokes about 10 cigarettes a day. 33 Clinical Cases Your chance to work Mr. Hart was admitted for gastric banding surgery. The admission nurse collected the following information: PMH: hypertension, raised cholesterol, peripheral vascular disease, gout, hypothyroidism, asthma FH: father died of a heart attack at the age of 55 mother had bypass surgery 15 years ago Medication history: Bendroflumethiazide 2.5mg PO every morning Beclometasone INH 200 mcg 2 puffs BID, PRN salbutamol His GP prescribed him a statin (unsure which) but he thought it was causing him diarrhoea & flatulence so he stopped taking it.

18 Clinical Cases Your chance to work Mr. Hart was admitted to Surgical Intensive Care Unit after a successful surgery and the following tests were completed: Sodium 135 mmol/l, Potassium 3.1 mmol/l Urea 9.0 mmol/l, Creatinine 130 micromol/l Bilirubin 10 micromol/l ALT 60 IU/L, ALP 95 IU/L, GGT 50 IU/L Hb 14.9 g/dl, WBC 9.6 x10 9 /L, Platelets 163 x10 9 /L Cholesterol 6.5 mmol/l, HDL 0.9 mmol/l, LDL 5.6 mmol/l Triglycerides 1.7 mmol/l Troponin T 3.24, Creatine Kinase 177 The registrar wants to start DVT prophylaxis Clinical Cases Your chance to work What would you recommend to start Mr. Hart on at this stage for DVT Prophylaxis?

19 Clinical Cases Your chance to work Mr. Hart developed fever on his third day post surgery. U&E and CBC were completed major change: WBC 18 x 10 9 /L (from 9.6 x 10 9 /L pre-op) Preliminary blood tests showed gram-positive cocci in clusters. He was referred to the infectious disease team. Meanwhile the registrar wants to initiate Vancomycin for Mr. Hart to cover the possibility of Staphylococcus aureus bacteremia. Review Mr. Hart s case & recommend an appropriate management plan for his current infection. Clinical Cases Your chance to work Ms Virginia Mulligan is a 36 year old patient with type 1 diabetes and renal failure currently receiving maintenance hemodialysis treatment 3 times weekly. She has a past medical history of, anemia in CKD with hemoglobin between 8.5 and 10 g/dl, diabetic gastroparesis, and hypothyroidism. Virginia was recently diagnosed with epilepsy (1 month ago). She was commenced on phenytoin 100 mg TID maintenance dose after appropriate loading. 38

20 Clinical Cases Your chance to work Her current medications include: IV epoetin alfa 6000 units 3/week IV iron 100 mg IV 3/week IV calcitriol 0.5 microgram 3/week SC insulin stable therapy for > 5 years thyroxin 75 microgram po daily multivitamin 3/week 39 Clinical Cases Your chance to work Lab results: HGB: 9 g/dl WBC: 9.6 x 10 9 /L Albumin: 2.7 g/dl (normal range 3.5 to 5 g/dl) phenytoin level: 5 mg/l (normal range mg/l) What would you recommend at this stage? 40

21 Clinical Cases Your chance to work Two weeks later, Ms Mulligan presented at dialysis unit with fever 39 C. Upon examination, she was lethargic and tachycardic. Her dialysis line site was erythematous with pussy discharge. Blood test revealed she had leukocytosis (WBC: 17 X 10 9 /L). The patient was admitted to the ward and septic workup sent (swab from central line, blood culture). Her old catheter was removed and a new line inserted in a different site. Septic workup revealed the following: Specimen Culture results Blood Candida albicans Catheter tip >100 cfu* Candida albicans (*Colony Forming Units) What would you recommend to start the patient on at this stage? 41 Clinical Cases Your chance to work Mr. Bert is a 79 year old gentleman who lives in a nursing home. He has a history of hypertension and diabetes mellitus. He was seen 2 months ago by his GP because he was struggling to sleep at night, apart from that he was OK. Medication history: Furosemide 20 mg po bid Glibenclamide 5 mg po with breakfast Lorazepam 1 mg po at bedtime Over the last 4 days, Mr. Bert has been feeling unwell and has become confused. He fell over while trying to leave his bed this morning. What do you think could explain Mr. Bert s symptoms? 42

22 Clinical Cases Your chance to work An initial diagnosis of fall due to a drug related adverse event was made. A decision was made to admit Mr. Bert to the Care of the Elderly ward for observation. All his medications were held and he was given an injectable opiate for pain. Luckily his Xrays showed no fractures. Mr. Bert became more alert in the following few days. The ward SHO has contacted you to review his medication, assist him with his discharge prescription as well as choosing appropriate pain relief. Review Mr. Bert s case and recommend an appropriate management plan 43 Outline of this session Introduction and definitions 10 min Practical clinical guidance, sources of information 15 min Case studies in small groups Feedback from the groups Conclusion & take home messages 60 min 20 min 10 min

23 Drug dosing in special patient populations This WS focused on obese renal geriatric Many other special patient populations neonates, infants, children pregnant and lactating underlying diseases etc. etc. Conclusions & Take Home Messages General references are for general patients But Many patients do not fit general

24 Conclusions & Take Home Messages Dose recommendations for special patients are limited to renal hepatic elderly But many patients do not fit one category only or any category at all Conclusions & Take Home Messages Drug dosing in patients with several comorbidities polypharmacy critical illness (ICU care) extreme age extreme weight Is often poorly studied & documented

25 Conclusions & Take Home Messages Be aware of limitations of medicine information sources Use specialized references Integrate available information & evidence into clinical picture and adjust when needed Consult colleagues, clinicians, experts to optimize and tailor treatment