Drug consent

Question 1

Indications for methotrexate

And mechanism

Answer 1

Inflammatory arthritis, especially rheumatoid
Psoriasis
Some chemo eg ALL

Inhibits dihydrofolate reductase

Question 2

Contraindications and interactions of methotrexate

Answer 2

Contraindic: men and women need to avoid pregnancy for >6 months after treatment has stopped
Interactions: trimethoprim or co-trimoxazole incr risk of marrow aplasia
High dose aspirin incr risk of methotrexate toxicity 2ndary to reduced excretion
** treatment of methotrexate toxicity is folinic acid**

Question 3

Adverse effects of methotrexate

Answer 3

Mucositis
Myelosupression
Pneumoniitis
Pulmonary fibrosis
Liver fibrosis

Question 4

Prescribing and monitoring methotrexate

Answer 4

Taken weekly, with folic acid 5mg once weekly coprescribed, to be taken on a different day.
FBC, U&Es and LFTs should be regularly monitored: weekly until therapy stabilised then every 2-3 months

Question 5

Bisphosphonates clinical use

Answer 5

Inhibit osteoclasts by reducing recruitment and promoting apoptosis
Use:
- prevention and treatment of osteoporosis
- hypercalcaemia
- Paget’s disease
- pain from bone metastases

Question 6

Adverse effects of bisphosphonates

Answer 6

Oesophagitis, oesophageal ulcers (esp with alendronate)
Osteonecrosis of the jaw (especially if IV in treatment of cancer. poor dental hygiene also a risk factor)
Incr risk atypical stress fractures of proximal femur
Acute phase following administration: fever, myalgia and arthralgia
Hypocalcaemia - usually unimportant

Question 7

Advice for patients taking oral bisphosphonates

Answer 7

• Swallow tablets whole
• with plenty of water
• whilst sitting or standing
• on an empty stomach
• at least 30 mins before breakfast or another oral med
• stand or sit upright for 30 mins after taking

Correct hypocalcaemia/low vit D before giving bisphosphonates.

Question 8

Indications for denosumab rather than oral bisphosphonates

Answer 8

Alendronate first line, then alternative oral eg risedronate.
Following this then only if certain criteria are met then increasing role for denosumab
Inhibits RANKL, generally well tolerated (other than dyspnoea and diarrhoea), given sc every 6 months.

Question 9

Statin mechanism

Answer 9

Inhibit action of HMG-CoA reductase, rate limiting enzyme in hepatic cholesterol synthesis

Question 10

Indications to take statin

Answer 10

All patients with established cardiovascular disease (stroke, TIA, ischemic heart disease, peripheral arterial disease)
Anyone with 10 year cardiovascular risk >10%
Patients with type 1 DM who were diagnosed >10 years ago or are age >40 or have established neuropathy

Question 11

What statin and when

Answer 11

Take at night as this is when majority of cholesterol synthesis occurs. Esp Simvastatin as has shorter 1/2 life
Generally atorvastatin 20 for primary prevention
Atorvastatin 80mg for secondary prevention

Question 12

Adverse effects of statins

Answer 12

Myopathy: myalgia, myositis, rhabdo etc. risks: increasing age, female, low BMI. more in simvastatn and atorva than pravastatin etc
Check LFTs at baseline, 3 months and 12 months for liver impairment. Discontinue if ALT rise and remain at 3x ULN

Question 13

Contraindications for statins

Answer 13

Pregnancy
Macrolides (erythromycin/clarithromycin) potential interaction and should hold statins whwilst taking
Avoid if history intracerebral haemorrhage (mixed evidence)

Question 14

, DOAC, steroid, , insulin, inhalers

Question 15

Metformin mechanism

Answer 15

Acts via AMP-activated protein kinase
Increases insulin sensitivity, and decreases hepatic gluconeogenesis.
First line for type 2 diabetes. also used in PCOS and NAFLD

Question 16

Adverse effects of metformin

Answer 16

GI upset common (nausea, anorexia, diarrhoea) and intolerable in 20%
Reduced vit B12 absorption - rarely a clinical problem
Lactic acidosis with severe liver disease or renal failrue - rare but important

Question 17

Contraindications to metformin

Answer 17

Chronic kidney disease ( review when eGFR <45, and stop when <30)
Periods of tissue hypoxia, eg recent MI, sepsis, AKI and severe dehydration as incr risk lactic acidosis
Iodine containing contrast media, as incr risk provoking renal impairment
Alcohol abuse is relative contraindication

Question 18

Starting metformin

Answer 18

Titrate up slowly to reduce incidence of GI side effects
If unacceptable SE, then consider modified release metformin

Question 19

important steroid counselling re withdrawal

Answer 19

If on long term steriods, double dose in intercurrent illness
Longer term systemic steroids suppress natural production of endogenous. Withdrawing suddenly may precipitate Addisonian crisis
gradual withdrawal for: >40mg pred daily for >1 week, >3 weeks of treatment, or recently received repeat courses

Question 20

warfarin mechanism

Answer 20

Oral anticoagulant
Inhibits enzyme reducing vitamin K to its active form
Vit K normally acts as cofactor in carboxylation of clotting factors II, VII, IX and X (1972), and protein C.

Question 21

Indications for warfarin

Answer 21

Mechanical heart valves.
- mitral valves generally need higher INR than aortic
Second line after DOACs. VTE: target INR = 2.5, if recurrent = 3.5.
- AF: target INR = 2.5

Question 22

Warfarin monitoring

Answer 22

INR ( ratio of prothrombin time for patient over normal prothrombin time)
Initially daily or alternate days until within therapeutic range.
Then twice weekly for 1-2 weeks. then weekly until at least 2 measurementts are within range
Thereafter, approx once every 3 months, depending on local protocols

Question 23

How to take warfarin

Answer 23

Usually once a day in the evening. Take around the same time each day.
This is so if neeed to change dose after a blood test can do the same day rather than waiting until the morning
does not normally upset stomach so can take with or without food.

Question 24

Things which may potentiate warfarin

Answer 24

liver disease
P450 enzyme inhibitors, eg amiodarone, ciprofloxacin
cranberry juice
Drugs displacing warfarin from plasma albumin eg NSAIDs
Drugs inhibiting platelet function eg NSAIDs

Question 25

Side effects of warfarin

Answer 25

Haemorrhage
Teratogenic (fine whilst breastfeeding)
Skin necrosis
Purple toes

Question 26

When on warfarin need medical help

Answer 26

Nosebleeds lasting >10 mins, blood in vomit, severe headaches. Any bleeding from cut or injury which will not stop or slow down

Question 27

Indications for DOAC

Answer 27

prevention of stroke in non-valvular AF
(according to CHADVASC)
Prevention of VTE following hip/knee surgery
Treatment of DVT and PE

Question 28

metered dose inhaler technique

Answer 28

Remove cap and shake
Breathe out gently
Put mouthpiece in mouth and as begin to breathe in slowly and deeply, press canister down and continue to inhale slowly and deeply
Hold breath for 10 seconds
Wait approx 30 seconds and repeat
Use doses as per label

Question 29

DOAC counselling

Answer 29

” blood thinning” medication helps reduce risk of blood clot formation, and so of stroke
Take once daily tablet, lifelong
Doesn’t require regular monitoring unlike older meds like wardarin
One of kidney function test before starting
Small risk serious bleeding events
No specif dietary/lifestyle alterations eneded
Seeek medical advice if any unexpected bleeding or injuries to head.

Question 30

Lithium indication

Answer 30

Primarily as mood stabiliser for bipolar disorder. Exact mechanism unknown, but thought to affect chemical messengerys in brain.
Usually taken lifelong with regular reviews by a psychiatrist. takes 1-2 weeks to work

Question 31

Monitoring for lithium

Answer 31

Prior tests: FBC, U&Es, TFTs, b-HCG (preg) and ECG
Following starting, lithium level taken after 5 days and then every week until stable for a minimum of 4 weeks
Lithium levels have to be taken 12 hours post-dose
Then taken 3 monthly
Narrow therapeutic range, so need intense monitoring
TFTs, U&Es, Ca taken every 6 months

Question 32

Lithium side effects

Answer 32

Renal toxicity
Nephrogenic diabetes insipidus
Hypothyroidism
- should all be picked up on monitoring blood tests

Question 33

Contraindications to lithium

Answer 33

1st trimester of pregnancy
breastfeeding
Cardiac disease
Significant renal impairment
Addison’s disease

Question 34

Mnemonic for drug discussion structure

Answer 34

ATHLETICS
A: action (how does drug work)
T: timeline (when to take)
H: how to take
L: length of treatment
E: effects (how long will take)
T: tests (monitoring or follow up)
I: important side effects (common and serious)
C: contraindications
S: supplementary advice