Pharmaceutical aspects of Iv medications

1. Pharmaceutical aspects of Iv medications

2. Aims and objectives • Rationale for IV use • Advantages and disadvantages of IV therapy • Roles and Responsibilities • Considerations for IV therapy • Prescribing • Preparing • Administering • Monitoring • National and Local Policies • Calculations

3. The Five Rights of Medicine Administration Right patient Right medicine Right route Right dose Right time ……every time!

4. Why IV? • Oral or other route of administration not suitable or available e.g. vomiting, diarrhoea, malabsorption, resting gastro-intestinal tract, low muscle mass • Where rapid effect or high/predictable concentrations essential • Medicine not effective via other routes e.g. gentamicin, benzylpenicillin

5. ADVANTAGES • Medicine gets into the circulation quickly • Rapid effect achieved • Predictable concentrations achieved i.e. 100% reaches systemic circulation • Some medicines cannot be given by another route e.g. gentamicin and meropenem

6. DISADVANTAGES • Risk of Infection • Severity of side effects • Multiple steps in preparation • Increased cost and nursing time • Increased complications e.g. extravasation, emboli, anaphylaxis reactions

7. IV Therapy incidents/reports • Published in The Times 18th May 2010 • Hospital is fined £100,000 over death of mother in drugs mix-up • Patient died hours after her son was born when a nurse at the Great Western Hospital in Swindon, Wiltshire, wrongly attached an epidural anaesthetic Bupivacaine to her intravenous drip instead of a saline solution. • NRLS incident reports 2005 -2006 • 24% of total medication incidents reported related to IV medications. • 93% of IV medication incidents reported to the NPSA were prescribing, administration or preparation errors. • 25 incidents of death reported to NPSA from IV medication incidents between Jan 2005 – June 2006. • NPSA Patient Safety Alert 20 – Promoting Safer use of injectable medicines • Highlights actions to be taken by healthcare providers to ensure safe and effective IV medication use. • All healthcare providers have to comply with guidance.

8. Professional Responsibility Prescriber and Administrator • Prescription is clear, unambiguous and legal • Medicine is essential and appropriate • Dose, route and rate is appropriate • Medicine is compatible with infusion fluid • Patient is not allergic to prescribed medication • Appropriate monitoring requirements are in place e.g. ECG machine for potassium infusions

9. Professional Responsibility Nurse • Must have completed IV Medicines Training, be certified competent and be aware of own limitations • Must not administer a drug if doubtful about any aspect of IV medicine prescription / calculation / preparation / compatibility / administration / monitoring • Must ensure that appropriate and current information sources are used

10. Professional Responsibility Pharmacist • Legal responsibility • Specialist knowledge • Access to specialist and up to date information • Can advise and provide support on any aspect of IV medicine use i.e. dose, calculations, method and rate of administration, diluents, stability and incompatibilities • Can provide advice via ward pharmacist or on-call pharmacist

11. Considerations for IV therapy Dose, Route and Rate • Is the dose appropriate for the IV route • Is the route suitable for the medicine and required rate? • Is the expected duration of treatment specified and/or appropriate? • Properties of the medicine? e.g. osmolarity, pH, irritant, short half life

12. Considerations for IV therapy Concentration, Diluent and Vehicle Concentration • Check that the concentration of the drug is within the recommended range for safety and efficacy and method of administration. e.g. erythromycin must be between 1-5mg/ml Diluent and Vehicle • Not always the same! !ALWAYS CHECK! e.g. clarithromycin must be reconstituted with water but diluted in sodium chloride 0.9% • Often used interchangeably by most staff i.e. most refer to both as diluent.

13. Considerations for IV therapy Compatibility Incompatibility occurs after mixing parental drugs if one or all of them become less effective. Changes that occur include: • Physical incompatibility e.g. precipitation, crystallisation, cracking e.g. TPN • Largely determined by pH and formulation • Chemical incompatibility e.g. degradation, inactivation or a new compound formed • Chemical reaction between drugs • Never add medicines to fluid unless compatibility assured • Never mix medicines together unless compatibility assured

14. Considerations for IV therapy Compatibility • Caspofungin is incompatible with diluents containing glucose • Erythromycin must be diluted to 5mg/ml for peripheral use • Phenytoin is given as undiluted bolus into a large vein or as an infusion diluted in NaCl 0.9%, can easily participate thus in- line filter is necessary • Vitamin K flush with glucose

15. Preparation: Factors Affecting Stability

16. Displacement Volumes and pH Displacement volume • Volume of fluid displaced by a powder when reconstituted • Important when part-vials are used • Mainly only relevant to paediatrics pH • Most medicines are stable at a specific pH • Rate of degradation often pH dependent e.g. amphotericin requires glucose pH>4.2

17. Labelling • When drugs are added to burettes, syringes or IV bags, the container must be clearly labelled with following: • Drug added • Dose added • Date and time of addition • Signature of practitioner

18. Rate of Administration Systemic damage • Furosemide  ototoxicity • Phenytoin  arrhythmias • Ranitidine  bradycardia • Vancomycin  red man syndrome Local damage • Pain • Extravasation • Phlebitis • Most IV bolus injections over at least 3-5 minutes • 95% of IV bolus injections given too fast!!!!!!! • Ensure device is capable of accurate delivery and desired infusion rate

19. Monitoring • Extravasation • Phlebitis more likely with • Irritants • Hypertonic solutions • Highly acidic solutions • Alkaline solution

20. Sources of Information • IV Drug Monographs/ Medusa website (http://www.injguide.nhs.uk/logon.asp) available on grapevine with log in details • BNF/BNFC • Product Information Leaflet • Medicines Information • Pharmacist • On-call Pharmacist • University College London Hospitals Injectable Medicine Administration Guide

21. Remember If in doubt, don’t administer! Most important consideration is the PATIENT They have to suffer the consequences

22. Calculations • 1gram (g) = 1000 milligrams (mg) • 1milligram(mg) = 1000micrograms(mcg) • 1microgram(mcg) =1000nanograms(ng) • E.g. Digoxin 250mcg = 0.25mg

23. Calculations • 1:1000 means 1g in 1000ml • How much adrenaline is there in 0.5ml if the strength you have is 1:1000 1:1000 = 1g in 1000ml • 1000mg in 1000ml • 1mg in 1ml • 0.5mg in 0.5ml

24. Calculations • A 6 year old boy (20kg) must receive a morphine infusion at a dose of 10mcg per kg per hour. The syringe is labelled 25mg in 50mls. What rate should infusion pump be set at? --------------------------------------------------------------------------------------------------------------------------------- 1. We need: 10mcg/kg/hour We have: 25mg in 50mls --------------------------------------------------------------------------------------------------------------------------------- 2. The boy weighs 20kg  we need to calculate the total dose for his weight : 10 mcg x 20 kg/hour=200mcg/hour --------------------------------------------------------------------------------------------------------------------------------- 3. We need to give 200mcg/hour and the syringe is labelled in milligrams: 1000mcg=1mg 200mcg/hour= 0.2mg/hour --------------------------------------------------------------------------------------------------------------------------------- 4. We have got syringe with 25mg in 50ml, we need to calculate in what volume is 0.2mg. 25mg…………..50ml 0.2mg …………..Xml 0.2 X= ---------- x 50 =0.4ml 25 --------------------------------------------------------------------------------------------------------------------------------- 5.The infusion pump should be set in 0.4ml/hour.

25. Calculations Dobutamine 250mg amp is diluted to a total of 50ml normal saline. A patient weighing 60kg must receive 5mcg/kg/min. How many mls per hour would you give the patient? ----------------------------------------------------------------------------------------------------------------------------------------- • We need: X mls/hour We have: 250mg in 50ml ----------------------------------------------------------------------------------------------------------------------------------------- 2. The patient is 60kg, we need to calculate the total dose for his weight: 5mcg x 60 / min = 300mcg/min ----------------------------------------------------------------------------------------------------------------------------------------- 3. Our result needs to be per hour and the dose is per minute: 300mcg / min x 60 = 18 000 mcg/hour ----------------------------------------------------------------------------------------------------------------------------------------- 4. Dobutamine is available in mg and our dose is in mcg: 1000mcg = 1mg 18000mcg/hour = 18mg/hour --------------------------------------------------------------------------------------------------------------------------------------- 5. Ampoules available are 50ml, we have to calculate the dose per 1ml 250mg in 50ml 250 ? in 1ml ------------ = 5mg 50 ---------------------------------------------------------------------------------------------------------------------------------------- 6. We have solution with 5mg in 1ml and need to give 18mg /hour. How many mls per hour do we give? 5ml …………1ml 18 18mg………….Xml X = -------- = 3.6ml /hour 5 ---------------------------------------------------------------------------------------------------------------------------------------- 7.We need to give to patient 3.6ml/per hour of our Dobutamine.

26. Questions?