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Pharmaceutical aspects of Iv medications

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Presentation on theme: "Pharmaceutical aspects of Iv medications"— Presentation transcript:

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 For NBM patients e.g. for TPN For drugs that have no oral formulation e.g. Ceftazidime, Piperacillin, Reopro For drugs that are not absorbed from GI tract e.g. Gentamicin, Vancomycin, Heparin For drugs that are destroyed by stomach acid e.g. Benzylpenicillin, Insulin ( broken down straight away by gut) When IM injection is unsuitable e.g. elderly emaciated patients, severe shock, paediatrics When you want a rapid response in emergencies e.g. anaphylactic shock, cerebral oedema, p psychiatric emergencies, acute pain management, inducing anaesthesia, severe dehydration E.g. Amiodarone- loading When predictable and/or high blood level are required e.g sepsis, theatre, anaesthetic induction( delivery of known quantity of drug over a known period of time) For drugs that have to be given by continuous infusion. Continuous infusion allows fine tuning and frequent adjustment to be made e.g insulin, morphine, drugs with short duration of action – inotropes. You can stop treatment and effects are quickly re erased. For drugs that have high first pass, which means that oral administration is relatively ineffective. Examples are Lignocaine, Adrenaline, Dopamine. IV administration gives direct access to blood stream and bypasses initial gut and liver metabolism.

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 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. NRLS – National Reporting and Learning System – (the body that collects information on medication errors and incidents around the UK and feeds into the NPSA)

8 Professional Responsibility
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 Prescriber and Administrator Doctors have responsibility for making the decision that a drug should be given by the IV route. They should ensure that the drug is essential (could an alternative be given?) Is the drug compatible with the prescribed infusion fluid. They must also ensure that the prescription is written correctly and clearly with all required information, Drug, Dose, Infusion fluid, Administration time and method (bolus, infusion) Both prescriber and administrator must ensure that appropriate monitoring equipment is available before medications is administered. Think about the patients’ condition electrolytes and diabetic status and give a drug in glucose if compatible and sodium levels are high. Also think about the concentration, some drugs can be over or under diluted and think about the flush.

9 Professional Responsibility
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 Nurse It is the responsibility of the nurse/midwife to ensure that he/she is deemed competent by the Trust/Hospital where employed. Staff member must also be confident of performing tasks once training is completed and singed off as competent. Each site/hospital will have local policies and member of staff needs to ensure that they are aware and follow policy.

10 Professional Responsibility
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 Pharmacist In special circumstances e.g. fluid restriction, not enough lines etc. the pharmacist can advice. Need for IV therapy needs to be considered first e.g. ciprofloxacin has a great bioavailability when given orally.

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 Is the dose and frequency appropriate for the route? IV doses can be different from oral doses e.g. ciprofloxaxin, metronidazole, ranitidine, hydrocortisone Is the route suitable for the medicine and required rate? IV Bolus e.g. amoxicillin, tramadol, IV intermittent infusion e.g. erythromycin IV continuous infusion e.g. heparin, insulin Centrally or peripherally Required rate Can increase risk of toxicity/adverse effects if administered at the incorrect rate. Too quickly – e.g. furosemide, vancomycin adverse effects Duration Once off prescription or to continue? Number of days? IV prescriptions valid for 24 hrs – need to represcribed on inpatient charts Properties pH – can precipitate if diluted to incorrect pH Irritant – extravasation, phlebitis, Short t1/2 – heparin, therefore continuous infusion

12 Considerations for IV therapy Concentration, Diluent and Vehicle
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. Concentration: Too concentrated or over diluted Too concentrated: Vancomycin or caspofungin, tigecycline Too dilute e.g.: Amiodarone, cyclizine, Concentration can be deciding factor on method of IV administration i.e.: bolus, central, peripheral, etc Diluent and vehicle Diluent – what fluid you use to reconstitute with Vehicle – infusion fluid or what is used to further dilute with

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 Ask audience – how are parental drugs mixed? e.g. In the same bag of IV fluids In the same syringe, diluted for a subcutaneous infusion In the same syringe neat for IM/IV injection In the same IV line or giving set In the same venflon/ cannula Y site compatibility is different to compatibility in a bag/syringe

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 Erythromycin for fluid restricted patients in ITU setting can be given as 50mg/ml via a central line 1g over 60 minutes (this is an UNLICENSED preparation/ method)

15 Preparation: Factors Affecting Stability
Effect Action Example Light  rate of degradation Ensure appropriate storage TPN, Pabrinex® Temperature  rate of degradation / microbial growth Aciclovir, TPN pH Add buffer Phenytoin (in glucose 5%) Concentration Less stable at changes in concentration Check volume Amiodarone, Amphotericin Adsorption Drug loss into plastic/glass Avoid or minimise contact Insulin, Nitrates e.g. GTN Light Causes photo degradation of some products. E.g. TPN, and most chemotherapy drugs are light sensitive and therefore must be covered whilst being infused. Temp Heat provides energy for chemical reactions and some drugs will not be stable once reconstituted. E.g. Aciclovir must be discarded after 12hours. Drugs normally stored in the refrigerator may be stable at room temp for short time only. E.g. lorazepam. pH The most likely reason for precipitation is the mixing in the infusion container/line of two medicines with very different pH values, especially if one is acidic and the other alkaline Concentration Once reconstituted the stability of some drugs varies at certain concentrations and therefore cannot be over diluted or too concentrated. Adsorption Some drugs bind to certain plastics depending on available surface area, diluents, flow rate, temperature, time and pH.

16 Displacement Volumes and pH
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 Displacement value example: The displacement value of Augmentin® / Co- amoxiclav is 0.5ml/ 600mg Thus when 100mg is needed 11.5 ml of WFI is added to the vial (giving a solution of 600mg in 12ml= 50mg/ml) and then 2 ml is used. pH example: IV Amiodarone pH is and therefore only stable in glucose 5% (pH ) IV cyclizine pH is and is also only stable in glucose, can be diluted to 1:1 but this is unlicensed. IT MUST BE FLUSHED WITH GLUCOSE Phenytoin pH is 12 and therefore only stable in NaCl 0.9% ( use an inline filter) (Can also be given as a bolus in a central line)

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 Important that all products are correctly labelled for identification. Any additions made to IV fluid bags must be labelled using the IV additive labels and attached to the IV bag/syringe. Ensures that errors in administration are minimised. All IV doses administered must be recorded on the drug chart and fluid balance chart.

18 Rate of Administration
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 Systemic damage Furosemide  ototoxicity Phenytoin  arrhythmias Ranitidine  bradycardia Vancomycin  red man syndrome Local damage Pain Extravasation Phlebitis

19 Phlebitis more likely with
Monitoring Extravasation Phlebitis more likely with Irritants Hypertonic solutions Highly acidic solutions Alkaline solution Extravasation of drugs i.e. leakage of drug outside the vein into the surrounding tissues can result in severe tissue damage and necrosis. Phlebitis - inflammation of the vein Phlebitis is more likely to occur the narrower the vein Irritants like: cytotoxics, erythromycin hypertonic solutions (glucose >10%) highly acidic solutions like ciprofloxacin, amiodarone alkaline solutions like aciclovir, sodium bicarbonate

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 Many different sources of information available to staff which they can refer to and will usually provide answer to any query they may have regarding the preparation of the drug required. Another source is the University College of London Injectable Medicines Administration Guide produced by the pharmacy department.

21 Remember If in doubt, don’t administer! Most important consideration is the PATIENT They have to suffer the consequences Final reminder that if they are unsure of anything don’t administer the medication. Always investigate any irregularities and double check details. The most important person to remember is the patient. They are already unwell and if anything is wrong they have to suffer the consequences. They are innocent and rely on you to know what you are doing. Don’t put them at unnecessary risk.

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 mcg/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 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 = mcg/hour 4. Dobutamine is available in mg and our dose is in mcg: 1000mcg = 1mg mcg/hour = 18mg/hour 5. Ampoules available are 50ml, we have to calculate the dose per 1ml 250mg in 50ml ? 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 18mg………….Xml X = = 3.6ml /hour 5 7.We need to give to patient 3.6ml/per hour of our Dobutamine.

26 Questions?


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