Prescribing - T Year Flashcards
1.1 Prescribing drugs for inpatients
What are once-only prescription?
*LOB: Describe the principles of once-only, regular, as required and infusion prescriptions for inpatients
Does not reccur.
“One Dose Only”
In a paper drug chart they have their own section.
Medication that needs to be given once
1.1 Prescribing drugs for inpatients
What are as required prescription?
*LOB: Describe the principles of once-only, regular, as required and infusion prescriptions for inpatients
Also known as PRN
Can be given for the listed indications such as an antiemetic prescribed incase the patient continues to feel nauseous.
May show maximum frequency
And maximum duration
-this enforces a level of medical review
1.1 Prescribing drugs for inpatients
What are infusion prescription?
*LOB: Describe the principles of once-only, regular, as required and infusion prescriptions for inpatients
Using a drip or pump over a period of time
Rate of substance is a crucial determinant of its clinical affect.
The rate can be titrated to change the effect of the drug.
Rate of Infusion
And Duration is required.
1.1 Prescribing drugs for inpatients
What are the different types of prescriptions?
*LOB: Describe the principles of once-only, regular, as required and infusion prescriptions for inpatients
Typical
Scheduled (regular and once only)
As Required
Titratable
IV, NG, some drugs
Atypical
Oxygen
1.1 Prescribing drugs for inpatients
What are the components of a prescription?
*LOB: Describe the essential components of each prescription type
Drug Name
Date and Time
Patient name and details
Allergies noted
Dose
Route
(Max) Frequency
Duration
Indication/ order comments
You can add a stop.
1.1 Prescribing drugs for inpatients
Pros and Cons of Electronic and Paper charting
*LOB: Discuss the differences between paper and electronic prescribing for inpatients
Pro Electronic
Can colour code given, due etc
Can show doses that have been given and which time
Can time doses specificaly.
Can flag allergies etc.
Access to patient data
Pro Paper
Seperate section for One Dose Only
Doesnt rely on systems if outages occur
Con Electronic
Technical outage, must have skill to prescribe on paper
Poorly designed systems show too much data
Con Paper
Increased error risk
Handwriting
Time consuming
Not as much data.
1.1 Prescribing drugs for inpatients
How do you review existing prescriptions?
*LOB: Describe an approach to the critical appraisal of existing prescriptions for inpatients
PAIRS
- Prescription Writing
- legible, legal, correct, complete, indications
- Adverse Effects
- allergies, intolerance, adverse effects
- Interactions
- Drug-drug, drug-disease, OTC, recreational, cautions and contras
- Rational Treatment
- appropriate drug and dosage, can any others be stopped/ tapered?
- Similarities
- Pharmacologically similar drugs, are they on more than 1 drug?, sometimes appropriate to intensify therapy but worth double-checking risks.
1.1 Prescribing drugs for inpatients
Sources for Prescribing
*LOB:Describe the sources of information available to guide prescribing for inpatients
Local Support and written guidance incl senior colleagues
Formularies- BNF
National Guidance
Peer Review Literature
Senior Colleagues
Other respected guidace
Textbook (informal support)
Online resources (informal support)
1.1 Prescribing drugs for inpatients
What is the prescribing process?
*LOB: Demonstrate safe and effective (simulated) prescription writing for common inpatient prescribing tasks
- Define the problem
- Define the therapeutic object/ drug
- Choose a Tx
- Efficacy
- Safety
- Tolerability (cost) - Start a Tx
- prescription writing
- administration
- proving patient information - Monitor Effects
- Stop if appropriate.
1.1 Prescribing drugs for inpatients
How can you ensure safe prescribing?
*LOB: Demonstrate safe and effective (simulated) prescription writing for common inpatient prescribing tasks
Review PAIRS when prescribing
Positive patient identification
Use formularies and local advice.
Check frequency- methotrexate and alendronic acid are accidental daily not correctly weekly.
Check you NSAIDs- make sure they are balanced well and not overtly prescribed. Set a limit (ie 7 days)
Double check if brand name doesnt include same medication ie) CoCodamol and Paracetamol
1.1 Prescribing drugs for inpatients
Best practice for abbreviations etc.
*LOB: Demonstrate safe and effective (simulated) prescription writing for common inpatient prescribing tasks
If using a brand name which is essential, in comments give the drug components.
Combined drugs may have approved names such as 30/500, you MUST use this.
ALWAYS complete the allergies field.
1.2 Prescribing intravenous fluids
What are crystalloids?
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
True solutions
Small molecules dissolved in water- salts and sugars
Sodium Chloride 0.9%
Glucose 5% (dextrose)
Hartmann’s Solution (compound sodium lactate)
Hartmann’s potassium is fixed, the others can be modified.
1.2 Prescribing intravenous fluids
Why is Hartmann’s used?
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
- Balanced pbysiological solution
- More closely approximate serum and ECF electrolytes
- Doesnt change the concentration of serum that much
- Lactate is a source of bicarbonate
- Potassium of Hartmanns is fixed.
The 5mmol K+ is not to have a therapuetic affect but to make hartmanns indifferent to the serum potassium concentration. Doesnt matter how much Hartmann;s that infused, it shouldnt cause a K+ error.
1.2 Prescribing intravenous fluids
What is the consequence of changing the potassium chloride.
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
The amount of potassium chloride can vary but is fixed at manufacture.
By changing the potassium, you also change the chloride amount.
For example, Sodium Chloride 0.9% has a Cl- of 154, but Sodium Chloride 0.9% with potassium chloride 0.3% has a Cl- of 194.
Remember this is concentration- so 40mmol/L at 0.5L = 20mmol given
1.2 Prescribing intravenous fluids
What are colloids?
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
Has a crystalloid base like Sodium chloride .
Includes large osmotically active molecules
such as albumin and gelatin
These make it a colloid.
Understand where the volume will go.
1.2 Prescribing intravenous fluids
Where does the volume of infused fluids go?
5% Glucose
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
THINK: 5% Glucose
A way to infuse pure water
Isotonic in the immediate location just at the point it starts mixing with blood, prevents water moving into cells (prevent lysis)
The Glucose is taken up by cells
Pure water is left,
Nothing stops the water moving so water distributes evenly across the 3 spaces.
1.2 Prescribing intravenous fluids
Where does the volume of infused fluids go?
Sodium chloride 0.9%
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
Sodium cannot pass to cells.
It has the same concentration as serum
Therefore the sodium and water stays in the intersitium and intravascular spaces.
The water doesnt move into cells as it stays in the extracellular compartments, ensuring the osmolality is preserved and does not change with the increase of sodium.
Losing about 80% into interstitium but useful for increasing circulating volume in the intravascular space.
1.2 Prescribing intravenous fluids
Where does the volume of infused fluids go?
Albumin 4.5%
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
Colloid
Large osmotically active moleucle cannot cross the intravascular membrane
The fluid can also not cross the membrane and retained intravascular and expands volume
HOWEVER, in sick pateints, this barrier is leaky and the colloid escapes in the interstitium, taking water with it.
Balance pharmacy risks (hypersensitvity) with effectivity.
Crystalloids are still favoured.
1.2 Prescribing intravenous fluids
How are fluids distributed?
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
**Areas for fluid: **
1) Intracellular
2) Extracellular
- Interstitial
- Intravascular
Mechanisms of control
Na/K/ATPase Pump, constrains potassium to intracellular, sodium to extracellular. Water can move between the two.
Large osmotic molecules ensures that osmolality of serum/ intravascular space is higher than the osmolality of interstitial water. So water always moves interstitial to intravascular- keep water in the blood.
1.2 Prescribing intravenous fluids
What needs to be matched when prescribing IV Fluids?
*LOB: Describe the essential principles of maintenance fluid prescriptions, accounting for sodium, potassium and water requirements
- Daily maintenance requirements
- Additional ongoing losses
- Existing deficits
1.2 Prescribing intravenous fluids
What are daily maintenance requirements?
*LOB: Describe the essential principles of maintenance fluid prescriptions, accounting for sodium, potassium and water requirements
lost per day
25-30ml water lost per kg of body
Sodium and potassium 1mmol each per kg of body
1.2 Prescribing intravenous fluids
How to plan maintenance fluids.
*LOB: Describe the essential principles of maintenance fluid prescriptions, accounting for sodium, potassium and water requirements
Using the 25ml/Kg rather than the 30 as you end up dividng by 24 hours.
You can be approximate.
This person needs 80mmol of sodium, 80mmol of potassium
Half a litre of Sodium chloride 0.9% will give 72mmol (close enough) of sodium and gives half a litre of water
Give the rest of the water with Glucose 5%
This provides the daily glucose.
1.5L of glucose
For potassium, hers is normal, so need to give the potassium chloride.
The potassium chloride 0.3% is the closest.
1.2 Prescribing intravenous fluids
Maintenance fluids Prescription
*LOB: Describe the essential principles of maintenance fluid prescriptions, accounting for sodium, potassium and water requirements
2L of water 24 hours
77mol Sodium
80mmol Potassium
1.2 Prescribing intravenous fluids
How to prescribe maintenance fluids (stepwise).
*LOB: Describe the essential principles of maintenance fluid prescriptions, accounting for sodium, potassium and water requirements
1) decide how to provide 1mmol/kg/day of sodium
2) Calculate and prescribe the hourly infusion rate (1ml/kg/h)
3) Make up the rest of water with 5% glucose
4) Make up potassium if renal fucntion and serum potassium is normal
1.2 Prescribing intravenous fluids
What are the potassium options?
*LOB: Define crystalloid and colloid fluid solutions and give examples of each
Potassium Chloride 0.15% 20mmol / L of K+
Potassium Chloride 0.3% 40mmol / L K+
So half a liter of 0.3% will give 20mmol of potassium.
1.2 Prescribing intravenous fluids
What is fluid resuscitation?
*LOB: Describe the essential principles of fluid resuscitation
Sequential fluid challeneges
Most be assessed and responded afterward.
By increasing fluids, we increase LV filling, therefore stroke volume should increase.
And therefore can help with Cardiac output
HOWEVER this has a limit if the LV is overstretched, increased filling can reduce stroke volume.
1.2 Prescribing intravenous fluids
How is LV filling increased?
*LOB: Describe the essential principles of fluid resuscitation
Sodium containing crystalloid solutions.
0.9% Sodium Chloride or Hartmann’s
As this increases the intravascular water and expands.
Only 20% remains, but in the first few minuets this wont have entered the interstitium yet and so the first few minuets is important to observe.
Rarely use colloid (technically blood products are)
NEVER GLUCOSE
NEVER ADDED POTASSIUM
1.2 Prescribing intravenous fluids
What to prescribe?
*LOB: Describe the essential principles of fluid resuscitation
Volume 250-500ml (500 easier)
Infuse rapidly ~5min
Children 20ml/Kg
1.2 Prescribing intravenous fluids
Monitor Response
*LOB: Describe the essential principles of fluid resuscitation
Hypotension
Tachycardia
Oliguria
AKI
GCS
Lactate
Always observe what was derranged first
IF NO CHANGE, check and repeat
If deteriorate, stop and review
Improvement? Monitor and repeat if needed
1.2 Prescribing intravenous fluids
Adverse effects of fluids
*LOB: Describe the essential principles of fluid resuscitation
Oedema (expected)
Pulmonary Oedema suggests end of starling curve
Breathlessness
Electrolyte derrangement
Hyperchloraemic metabolic acidosis.
1.3 Calculations in prescribing
What units are used in prescribing?
*LOB: Describe (in overview) the International System of units (including base units, derived units and prefixes) as this relates to the use of medicines
Majority are SI units (if in doubt think base 10)
Meter, second, mole, kilogram
Some drugs, such as insulin and heparin, are dosed in units of biological activity.
1.3 Calculations in prescribing
Abbreviations in prescribing
*LOB: Describe (in overview) the International System of units (including base units, derived units and prefixes) as this relates to the use of medicines
Liters are always an uppercase L
g (gram), L (litre) and mol (moles), and their ‘milli’ counterparts (mg, mL and mmol).
1.3 Calculations in prescribing
How to quanitfy body size?
*LOB: Demonstrate the calculation of ideal body weight and adjusted (dosing) body weight, and describe their interpretation and use
- Total body weight- TBW
- Calculated derivatives of weight
- Estimate of Body surface area (haematology and chemo drugs)
BUT TBW shoudl be capped, because 50% extra weight doesnt always mean 50% more drug but can soemtimes nearly double the drug- not likely to occur.
We can cap the drug. (Crude)
**Using Ideal body weight from height ** which is ideal as is easy to calculate and presumes what the liver capacity excretion capacity probably is
1.3 Calculations in prescribing
What is the ideal body weight formula?
*LOB: Demonstrate the calculation of ideal body weight and adjusted (dosing) body weight, and describe their interpretation and use
(0.91 x (height in cm-152.4)) +45.5
You can round slightly
+50 for men
1.3 Calculations in prescribing
How much of excess weight important to drug dosing?
CALCULATING ADJUSTED BODY WEIGHT
*LOB: Demonstrate the calculation of ideal body weight and adjusted (dosing) body weight, and describe their interpretation and use
Crudely divide into lipid and lean
IBW + (0.4 x Excess weight)
Why? Insoluble in lipid
Lean volume does effect distribution.
1.3 Calculations in prescribing
Which body weight method is used when?
*LOB: Demonstrate the calculation of ideal body weight and adjusted (dosing) body weight, and describe their interpretation and use
Why? Total body weight for the demo patient claculated 560mg, capped weight 500mg, adjusted 420g, ideal 300mg all for the same drug.
1.3 Calculations in prescribing
What affects drug dosage?
*LOB: Describe the clinical variables that may need to be considered in determining drug dosage regimens
Age
Indication
Formulation
Body size
Co-morbidity
Administration route
Body composition
Concurrent treatment
Practicability
Renal function
Plasma concentration
Hepatic function
Cardiac output
1.3 Calculations in prescribing
Variables in infusion
*LOB: Describe the clinical variables used in the prescription and administration of drugs in solution and how to convert between these
Mass
Volume
Time (s, min, h, day)
Concentration = Mass/Volume
Rate = volume/time or mass/time or mass/bodyweight/time
1.3 Calculations in prescribing
Converting calculations
*LOB: Demonstrate how to convert between concentrations expressed as percentages, 1-in-n, and mass/volume
Always follow the units
Always double check
Balance both sides
Use the triangle
1.3 Calculations in prescribing
What is percent?
*LOB: Demonstrate how to convert between concentrations expressed as percentages, 1-in-n, and mass/volume
0.9% =0.9kg in 100L
=0.9g in 100mL
=9g/L
=9mg/mL
1.3 Calculations in prescribing
What is ratio strength?
*LOB: Demonstrate how to convert between concentrations expressed as percentages, 1-in-n, and mass/volume
Adrenaline 1:10000
c:x
kg in kg
g in mL
1g adrenaline in 10000mL of water
1mg in 10mL
1.4 Prescribing drugs for outpatients
What is an outpatient prescription?
*LOB: Describe the essential components of an outpatient (FP10) prescription
FP10 and inpatient. FP10 is a complete record in itself- must have a lot more details. Age is required in under 12 years old.
Prescribers address, signature and date are legally required.
1.4 Prescribing drugs for outpatients
Considerations in chronic prescribing
*LOB: Compare and contrast the general considerations in prescribing for acute vs. chronic conditions
- Stability or predictability of person’s condition
- Drug/disease monitoring requirements
- Unfamiliar/specialist treatment
- Multiple/conflicting guidance sources
- Convenience and practicality of administration
- Adherence with treatmetn and aids to improve this
- Potential for misuse
- Carbon footprint
- Treatment cost
- Repeat prescribing
- Remote prescribing
1.4 Prescribing drugs for outpatients
Compliance Aids
*LOB: Describe the range of, and indications for, medication compliance aids to improve adherence
multi-dose drug dispensing systems (often referred to as ‘Dosette Boxes’, or sealed (‘blister packs’).
Potential advantages of multi-dose drug dispensing systems: Reduces complexity for the person taking the medicines and/or their carers; acts as a memory aid; may reduce dosing or timing errors
Potential disadvantages of multi-dose drug dispensing systems: Costly, time-consuming and labour-intensive to fill; risk of dispensing errors; may reduce patient independence and their familiarity with their medicines; not all medicines are suitable for re-packaging; does not improve intentional non-adherence (reported to account for around 50% of non-adherence in patients over 65 years)
1.4 Prescribing drugs for outpatients
Remote Prescribing
*LOB: Discuss the additional challenges that may be faced when prescribing remotely
- Patient safety is the first priority
- Identify venerable patients and take steps to protect them
- Identify yourself fully to the patient (name, role, and professional registration details if online) and explain how the remote consultation will work
- Explain that you will only prescribe if it is safe to do so; if you have sufficient information about the patient; and if information can be shared with other healthcare providers if necessary. If these criteria are not met, you should signpost the patient to other services to meet their needs.
- Obtain informed consent
- Undertake adequate clinical assessment
- Explain the options in a way the patient can understand
- Provide appropriate follow-up and share information with other healthcare professionals as appropriate
- Keep full notes of the clinical encounter and decisions
- Keep up to date with training, support and guidance
THE LAW OF POTASSIUM CHLORIDE
Example 0.3%
The maximum rate at which potassium can be infused is 10 mmol/h.
so 40mmol can be given a maximum over 4 hours
1L over 4 hours = 250mL/hr
Can only be given with glucose or sodium chloride.
THE MAXIMUM CONCENTRATION OF LIDOCAINE
Maximum dose of lidocaine (plain, without vasoconstrictor) is 4.5 mg/kg (not to exceed 300 mg)
Example patient weight - 10 kg
Total dose that can be used for this patient = 4.5 mg/kg x 10 kg = 45 mg
What patient factors increase the risks associated with prescribing?
Age extremes, renal/hepatic impairment, comorbidities, and genetic predispositions.
What drug factors increase the risks associated with prescribing?
Polypharmacy, narrow therapeutic index, and potential for interactions.
What system factors increase the risks associated with prescribing?
Communication errors, prescriber fatigue, and limited access to updated information.
Define allergy as related to drugs.
An immune-mediated reaction that can lead to severe responses (e.g., anaphylaxis, urticaria).
Define intolerance as related to drugs.
A non-immune, often dose-related reaction, generally less severe and more predictable.
How does renal impairment affect prescribing decisions?
Requires dose adjustments or alternative drugs to prevent toxicity.
How does hepatic impairment affect prescribing decisions?
Alters drug metabolism, necessitating careful selection and dosing.
How does cardiac failure affect prescribing decisions?
Caution with drugs that may exacerbate fluid overload or arrhythmias.
How do mental health conditions affect prescribing decisions?
Monitor for interactions with psychotropic medications and ensure adherence.
How does pregnancy affect prescribing decisions?
Avoid teratogens and choose medications with established safety profiles.
How does breastfeeding affect prescribing decisions?
Consider drug excretion into breast milk and potential infant exposure.
How do extremes of age affect prescribing decisions?
Adjust dosing in neonates, children, and the elderly due to altered pharmacokinetics/dynamics.
How does end of life affect prescribing decisions?
Prioritize quality of life with symptom control and deprescribe non-beneficial medications.
What sources of information guide prescribing decisions in special circumstances and comorbidity?
Clinical guidelines/formularies: BNF, NICE guidelines, and specialty-specific protocols.
What are the risks of ‘over-prescribing’?
Polypharmacy increases risk of interactions, cumulative side effects, and patient non-adherence.
What is essential for minimizing unnecessary drug burden?
Regular medication review is essential for deprescribing.
Define side effect.
Often a known, sometimes tolerable effect occurring at therapeutic doses.
Define adverse drug reaction.
An unintended, harmful response that may require intervention or cessation.
What is the mechanistic basis of adverse drug reactions?
Related to the pharmacology of the drug—overdose effects, receptor overactivation/blockade, or off-target effects.
What are immune-mediated reactions?
Include hypersensitivity reactions that may not be dose-related.
How are adverse drug reactions classified in terms of dose-relationship?
Type A: Predictable and dose-dependent; Type B: Unpredictable, idiosyncratic reactions.
How are adverse drug reactions classified in terms of time course?
Immediate versus delayed onset.
What are susceptibility factors for adverse drug reactions?
Patient-specific factors such as age, genetic factors, and existing comorbidities.
What sources of information help identify and manage adverse drug reactions?
Drug monographs and bulletins provide detailed information on ADRs.
What are online databases and reporting systems for adverse drug reactions?
MHRA, FDA, and local pharmacovigilance programs.
What clinical guidelines help with monitoring and management of adverse drug reactions?
Evidence-based recommendations for monitoring and management.
Define pharmacokinetic interactions.
Interactions affecting absorption, distribution, metabolism, or excretion.
Give an example of a pharmacokinetic interaction.
Grapefruit juice inhibiting CYP3A4, altering drug levels.
Define pharmacodynamic interactions.
Interactions at the receptor or effect level, leading to synergistic or antagonistic outcomes.
Give an example of a pharmacodynamic interaction.
Concurrent use of sedatives resulting in excessive CNS depression.
What sources of information help identify and manage drug interactions?
Drug interaction databases are electronic tools integrated into prescribing systems.
What are clinical decision support systems?
Alerts and evidence-based recommendations.
What is a practical approach to identifying and managing interactions?
Medication reconciliation: Systematic review of all patient medications.
What is the use of interaction checkers?
Regular use of digital resources to preempt potential interactions.
What is important for monitoring interactions?
Clinical and laboratory assessments to detect early signs of adverse interactions.
What should be done after identifying interactions?
Dose modification or alternative therapy after interdisciplinary review.
Define therapeutic index.
The ratio between a drug’s toxic dose and its therapeutic dose.
Why is the therapeutic index relevant?
Drugs with a narrow therapeutic index (e.g., warfarin, digoxin) require meticulous monitoring to avoid toxicity.
What pharmacological factors can increase risk in prescribing?
Drug properties: Potency, bioavailability, half-life, and metabolic pathways.
What patient variability factors can increase risk in prescribing?
Differences in drug metabolism and excretion that can alter drug efficacy and safety.
What human factors can increase risk in prescribing?
Communication gaps, cognitive factors, and system issues.
Types of Hypersensitivities
What is DoTS?
Use DOTS to represent dose related toxicity for each reaction type
What are the types of time related drug reactions/ ADR?
And a common error that people make with these types of reaction is that they assume that is the drug that was started most recently.
Give some of the susceptibility factors
Reporting ADRs: the Yellow Card scheme
- Prescribers are asked to report
- All suspected ADRs for drugs marked with a black triangle in the BNF (this denotes drugs subject to additional monitoring—including all new drugs)
- All suspected ADRs in children
- All serious suspected ADRs in other circumstances
What are drug interactions?
- Pharmacokinetics is about how the body handles drugs ADME
- Absorption from the site of administration
- Distribution between tissues and body compartments
- Metabolism to active or inactive products
- Excretion from the body
- Pharmacodynamics is about what the drug, at known concentrations, does to the body
Example of ADME interaction?
- Digoxin is excreted into the urine by a transporter protein called P glycoprotein.
- Clarithromycin, which is an macrolide antibiotic, can inhibit P glycoprotein, therefore reduce digoxin excretion.
Cytochrome P450 Inducers
Narrow therapeutic window drugs
MIND THE GAP
Share pharmacodynamics examples
What increases/ stratifies ADR risk?
First Pass Metabolism Revision
Prescribing for Pregnancy consider….
- Effect of pregnancy on pharmacokinetics
- Effect of drug on foetus
What to avoid in breastfeeding?
- Cytotoxic drugs that may interfere with cellular metabolism of the infant (e.g. methotrexate &)
- Drugs of abuse, for which adverse effects on the infant during breastfeeding have been reported (e.g. amfetamine, cannabis, cocaine, heroin)
- Radioactive compounds (e.g. radioiodine)
Drugs with Caution for Pregnancy/ Infancy/ Breastfeeding
- Atenolol: because, unusually among beta blockers, it is water soluble, so more readily excreted in breast milk
- Aspirin : because of the risk of Reye’s syndrome in the infant
- Bromocriptine E: which can inhibit lactation
- Lithium: which is present in breast milk in concentrations that may cause toxicity
Cognitive bias in medicine
Steady state revision
How to adjust treatment?
- for example for pylori eradication, maybe after someone’s had a peptic ulcer treated. we might need to monitor our therapeutic objectives of achieving ulcer healing not just by symptom review, but by repeating an endoscopy, for example, six weeks after the original endoscopy.
- However, if someone is on, uh, proton pump inhibitors for more than a year, we should be monitoring serum magnesium levels,
How to test efficacy and safety of: ACE-inhibitors/ARB
• Efficacy: symptoms (i.e. if indication is heart failure) or blood pressure (if indication is hypertension)
• Safety: electrolytes (aim K+<6.0 mmol/L) and renal function 1-2 weeks after dose change (accept 30% rise in Cr/25% fall in eGFR)
How to test efficacy and safety of: Antidepressants
Efficacy: Symptom review at 2 weeks and 4 weeks after starting treatment. Change dose at 4 weeks if no effect, otherwise adjust at 6-8 weekly interval
• Safety: Symptom review
How to test efficacy and safety of: Azoles (e.g. fluconazole)
Efficacy: Resolution of infection (how this is judged will depend on the type, location and severity of fungal infection)
Safety: Monitor liver enzymes for toxicity in prolonged/high dose treatment
How to test efficacy and safety of: Antipsychotics
Safety: Monitoring for metabolic syndrome (weight, BP, glucose), clozapine may cause agranulocytosis (check FBC)
• Efficacy: Symptom review
How to test efficacy and safety of: Beta blockers
• Efficacy: Symptoms, heart rate (aim 55-60 beats/min for coronary artery disease)
• Safety: Bradycardia, hypotension, bronchospasm, can mask symptoms of hypoglycaemia/thyrotoxicosis
How to test efficacy and safety of: Bisphosphonates
• Osteoporosis: DEXA scan at 1-2 years
• Hypercalcaemia: calcium level and symptoms
• Safety: symptoms of oesophagitis, osteonecrosis of jaw (don’t start until vitamin D >30 ng/ml)
How to test efficacy and safety of: Calcium
• Efficacy: In hyperkalaemia, repeat 12-lead ECG and look for resolution of PR interval and QRS duration. Repeat dose if needed
How to test efficacy and safety of: Carbamazepine
• Efficacy: seizure frequency monitoring, symptoms of pain in trigeminal neuralgia, mood stability in bipolar disorder
Safety: Routine monitoring unlikely to coincide with hypersensitivity
How to test efficacy and safety of: Digoxin
• Efficacy: symptoms and heart rate
• Safety: periodic ECG (reverse tick is normal), electrolytes (hypokalaemia & hypomagnesaemia increase risk of toxicity)
How to test efficacy and safety of: Furosemide
• Efficacy: symptoms and signs of oedema, weight
• Safety: sodium, potassium and renal function
How to test efficacy and safety of: Gentamicin
• Efficacy: markers of resolution of infection (varies by indication, could include temperature, inflammatory markers, etc)
Safety: serum gentamicin concentration (note that in once-daily gentamicin dosing, there are two main methods for monitoring and dose-adjusting gentamicin: one is to measure a trough (pre-dose) concentration, as is done at St George’s and described in the Grey Book; the other is to measure the concentration at 6-14 hours post dose and then refer to the Hartford nomogram to determine when the next dose is given)
How to test efficacy and safety of: Heparins
• LMWH: Efficacy/safety anti-factor Xa (pregnancy only)
Safety: platelet count should be monitored
• UFH: Efficacy/safety APTT
How to test efficacy and safety of: Iron
• Efficacy: Expect Hb to increase by 20g/L per month
Safety:; Symptom review (e.g. constipation)
How to test efficacy and safety of: Laxatives
• Efficacy/safety: Stool chart
How to test efficacy and safety of: Metformin
Safety: Renal function measured annually (more frequently in renal dysfunction)
• Efficacy: HbA1c
How to test efficacy and safety of: Methotrexate
• Efficacy: depends on indication but could include improvement in symptoms/signs in rheumatoid arthritis (e.g. DAS28 score)
• Safety: FBC, renal and liver function 1-2 weekly until treatment establishment and 3 monthly thereafter
How to test efficacy and safety of: Phenytoin
Safety: Wait 7-days after dose change before checking concentration, cardiac monitoring (if acutely loading intravenously)
• Efficacy: Seizure control
How to test efficacy and safety of: Statin
• Efficacy: Aim for 40% reduction in non-HDL cholesterol
• Safety: liver function tests, muscle symptoms (and if present creatine kinase)
How to test efficacy and safety of: Sulfonylureas
Safety: Monitor renal function (avoid accumulation), hypoglycaemia episodes
• Efficacy: HbA1c
