Prescribing is something you'll do on a day to day basis. Over time certain medications will become incredibly familar and you'll be able to reel of the dose, common interactions and dose alterations without even stopping to think about it, but like everything it takes a bit of time. I've deliberately not included specific doses in a lot of this section because they can vary as guidelines change. 

Key things though, if you ever aren't sure, ask before you prescribe. 

Things to consider when prescribing? 

• Why am I prescribing the medication? 

  • What's the indication - particulary for antibiotics as it influences choice

• Is the medication / dose safe for the patient? 

  • Allergies / other contraindications 

  • Weight 

  • Renal or liver impairment 

• Does it need monitoring 

  • Drugs levels 

  • INR / APTT 

  • Renal / liver function

Always check: 

• Right drug for the right patient 

• Correct dose for age, weight, liver / renal function 

• Right route 

• Make sure they aren't allergic 

• Review common interactions 

Common pitfalls 

• Forgetting to review allergy status 

• Prescribing without reviewing bloods

• Not adjusting for weight 

• missed interactions 

• Duplicate prescriptions 

  • On paper drug charts you can miss things like paracetamol on the PRN and regular sides 

  • On EPMA you can get fatigued by options so be careful 

• No VTE prescribed 

  • if not prescribed a reason should be documented alongside a review date 

Antibiotics: 

• What are we treating 

  • Is it a skin, chest, abdominal, urinary infection or something else 

• Do we need cultures pre treatment 

  • Blood cultures 

  • Urine dip and culture 

  • Wound / skin / pus swabs 

Before prescribing:

• Follow local hospital guidelines - most trusts will have their own online guidelines 

  • These will offer advice by body system 

  • Usually have options for penicillin allergy 

  • Will also have advice for dose in renal impairment 

• Check the patients allergies 

• Be aware if monitoring is required 

  • Document timing of this and hand it over if it falls outside of your shift

    • Eg Chase gentamicin levels - Adjust dose as per nomogram 

• Try and document a review and/or stop date for the course 

VTE 

• Venous thromboembolism encompases both deep vein thrombosis and pulmonary emboli. 

• It occurs when blood clots within the venous system resulting in impaired blood flow and a whole host of other complications, due to a triad of vessel wall injury, stasis and hypercoagulabilty. 

• It is so important to be aware of an individual patients risk because there are an estimated 25,000 deaths per year across the UK attributed to hospital acquired VTE events. (1)

Reviewing risk:

• Most trusts will have a local VTE policy in place - check the intranet 

• Will score the patient based on VTE risk and bleeding risk 

• If no bleeding risk patient should be prescribed VTE prophylaxis 

• Check with seniors before you prescribe VTE particulary for surgical patients who might be going to theatre 

Risk assessment tools: 

• Local VTE assessment protocols 

  • Usually separate algorithms for medical, surgical, obstetric patients 

• WELLS score DVT / PE for patients where you suspect VTE

Pharmacological Prophylaxis 

• First line - usually a low molecular weight heparin 

• Ideally VTE risk is reviewed and prescribed within 14 hours of admission 

• Risk should be reassesed every 48 hours 

Mechanical prophylaxis 

• TED stocking - Provide a graduated pressure from distal to proximal portion of the leg to increase blood flow through improved action of the calf muscle pump 

• Flowtrons - Intermittent pneumatic compression devices stimulate blood flow through deep veins 

  • More common in theatre or on the stroke ward 

Diabetic Medications: 

• Huge topic and seems to change everytime you look! As a result it's not possible to go through everything but there are some key things that you should consider before prescribing anti-diabetic medications. (4) 

• Key things: 

  • What is the patient currently taking - Oral antidiabetics agents, insulin 

  • What is the current blood glucose level? 

  • Is the patient eating and drinking normally 

  • Are they on any other medications that might be affecting blood sugar control 

  • Are they are risk of hypoglycaemia? 

  • Do they have renal impairment? 

  • Do they have an intercurrent illness - some medications need to be temporarily stopped particulary if severe diarrhoea or vomiting - eg metformin or SGLT2 

Sliding Scales

Indications for initiating a sliding scale 

• Type 1 or type 2 diabetes with fasting period – more common in surgical patients 

• People with Type 1 diabetes who have not received background insulin

• Suboptimal diabetes management with HbA1C >69 mmol

• Most diabetics undergoing emergency surgery 

• Persistent hyperglycaemia (CBG >12 mmol/l) in perioperative period

  • Reduces risk of wound infection

Managing a patient on a sliding scale: 

• Generally, continue long acting at 80% normal dose 

  • Might be different depending on local policy 

• Insulin rate determined by blood glucose level and will alter with each CBG review 

• Omit other diabetes medication

• Hourly bedside CBG – as per protocol 

• Daily U&E’s for monitoring 

• Fluid running along side – standard 0.45%  NaCl + 5% Dextrose + 0.15% KCl

• Be aware patients can become hypoglycaemic on the VRII so may need to treatment for this. Can be oral or IV depending on CBG levels. 

Oxygen: 

• Oxygen should always be prescribed 

• Complications from over oxygenation can occur - Hypercapnic respiratory failure 

• Consider the target saturations 

  • Generally speaking - adjusting a patients target saturations requires senior approval 

  • Usually aiming 94% and above 

  • 88-92% in patients who are known CO2 retainers 

• Consider mode of delivery 

• If you have a patient with a worsening oxygen requirment or reduced oxygen saturations despite oxygen therapy - Escalate! 

  • Get an ABG if possible as it can tell us a lot about the patients respiratory status. 

IV fluids: 

• Head to the IV fluid section for this one! 

Pain and opioids: 

• Head to the pain section for this one! 

• But don't forget to prescribe PRN's like naloxone for safety when prescribing opioids 

Helpful people and resources: 

• Pharmacists - amazing help with pretty much anything medication related and always happy to help

• Seniors 

• BNF 

• Renal drug handbook - really really helpful for patients with kidney impairment for guiding the dose adjustment 

• Local antimicrobial guidelines 

• Trust or NICE guidelines for insulin, VTE, fluids

• Diabetic / Pain teams

Disclaimer:

This is a not for profit education resource designed for new resident doctors. All information serves as a guide to help doctors approach day to day life as an F1. It is not intended as a guide to patient care and should never be used as such or in place of advice of treating clinicians or published clinical guidelines. All cases are fictional and any resemblance is purely coincidental. Additionally all images are AI generated unless otherwise stated. 

References / Resources: 

1. Did you know? Working to prevent avoidable venous thromboembolism. (2020, July). NHS Resolution. https://resolution.nhs.uk/wp-content/uploads/2020/09/Did-You-Know_Venous-thromboembolism.pdf

2. Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism. (2018). NICE. https://www.nice.org.uk/guidance/ng89/chapter/recommendations 

3. Guidance on prescribing. (20 B.C.E.). BNF. https://bnf.nice.org.uk/medicines-guidance/guidance-on-prescribing/ (Resource) 

4. Diabetes - Type 2. (2016). NICE. https://cks.nice.org.uk/topics/diabetes-type-2/