Prescribing Safety #1

Question 1

When on Lithium longterm, what should be checked every 6 months?

Answer 1

• Renal Function (urea and electrolytes)
• Thyroid Function Tests

**whilst lithium can cause ECG changes there’s no need to repeat ecg periodically

Question 2

What is the safe range for lithium when doing Therapeutic drug monitoring, and when should it be done?

Answer 2

Range: 0.4-1.0 mmol/l

Take 12 hours post dose

Question 3

When should you do Therapeutic drug monitoring for ciclosporin?

Answer 3

trough levels immediately before dose should be taken

Question 4

A young girl with croup comes into ED.

Write a prescription for ONE drug that will help to relieve the girls’ symptoms.

Answer 4

Dexamethasone at 0.6mg/kg via the least invasive route

eg; for a 10kg girl Dexamethasone 6mg oral STAT dose

Even mild cases of croup benefit from oral corticosteroids, preferably dexamethasone as it has less mineralcorticoid activity than prednisolone.

Question 5

For antipsychotics, how frequently do you need to measure lipid levels and weight?

Answer 5

• At the start of therapy
• At 3 months
• Annually

Question 6

For antipsychotics, how often do you need to measure fasting blood glucose and prolactin?

Answer 6

• At the start of therapy
• at 6 months
• Annually

Question 7

For antipsychotics, how often do you need to measure FBC, U&E’s and LFT’s?

Answer 7

• At the start of therapy
• Annually
• **Clozapine requires much more frequent monitoring of FBC (initally weekly)

Question 8

Regular nebulised salbutamol is added to the drug chart for someone having an asthma exacerbation.

Write a prescription for ONE additional drug that will help to treat her asthma exacerbation.

Answer 8

Prednisolone 40-50MG PO OD

Question 9

Write a prescription for ONE drug that will help to treat the patients’ meningitis infection (unconfirmed pathogen)

Answer 9

either

Ceftriaxone 2g IV STAT

Cefotaxime 2g IV STAT

(every 12 hourly)

**benxypenicillin is only for confirmed cases of meningicocci, outside of hospital it is used intramuscularly (usually by GPs) in suspected cases of meningococci whilst transfer to hospital is awaited.

Question 10

Two possible prescriptions for a UTI in an elderly woman?

Answer 10

Trimethoprim 200mg PO BD

or

Nitrofurantoin 50mg PO QDS

Question 11

A woman who has recently been diagnosed with hypertension becomes pregnant. What anti-hypertensive is contraindicated in pregnancy?

Answer 11

ACE-inhibitors

Use nifedipine instead

Question 12

It is recommended that patients take ______ of their total oral morphine dose for breakthrough pain

Answer 12

It is recommended that patients take one-sixth of their total oral morphine dose for breakthrough pain

Question 13

The following drugs should be used with caution in patients with ischaemic heart disease:

Answer 13

• NSAIDS
• Oestrogens: eg; COC, HRT
• Varenicline (used for nicotine addiction)

Question 14

General factors that may potentiate warfarin

Answer 14

• liver disease
• P450 enzyme inhibitors (see below)
• cranberry juice
• drugs which displace warfarin from plasma albumin, e.g. NSAIDs
• inhibit platelet function: NSAIDs

Question 15

Inhibitors of the P450 system include - INR will increase

Answer 15

• antibiotics: ciprofloxacin, erythromycin
• isoniazid
• cimetidine,omeprazole
• amiodarone
• allopurinol
• imidazoles: ketoconazole, fluconazole
• SSRIs: fluoxetine, sertraline
• ritonavir
• sodium valproate
• acute alcohol intake
• quinupristin

Question 16

Inducers of the P450 system include - INR will decrease

Answer 16

• antiepileptics: phenytoin, carbamazepine
• barbiturates: phenobarbitone
• rifampicin
• St John’s Wort
• chronic alcohol intake
• griseofulvin
• smoking (affects CYP1A2, reason why smokers require more aminophylline)

Question 17

What is the WHO analgesia ladder?

Answer 17

1. Non-opiod analgesics
   Paracetamol
   NSAIDS inc aspirin
2. Mild opiod analgesics
   codeine
   dihydrocodeine
3. Strong opiod analgesics
   morphine