Adverse reactions

Question 1

Drug classes ordered in prevalence of adverse reactions?

Answer 1

NSAIDs (29.6%); Diuretics (27.3%) ; Warfarin (10%)

Question 2

Side effects to NSAIDs

Answer 2

Bleeding, renal impairment and wheezing

Question 3

Side effects Diuretics

Answer 3

Hypotension (biggest cause of falls); electrolyte disturbances (monitor plasma potassium!)

Question 4

What is a useful response to dealing with a type A adverse reaction?

Answer 4

Reduce the dosage, since these are predictable

Question 5

Side effects TCAs? (type a)

Answer 5

anti-muscarinic

Question 6

Side effects Beta blockers (type a)

Answer 6

cold peripheries

Question 7

Beta blockers (type a)

Answer 7

bradycardia (below 60)

Question 8

Opioids (type a)

Answer 8

constipation or hallucinations

Question 9

Antibiotics (type a)

Answer 9

diarrhoea

Question 10

Ivabradine (type a) used for IHD and HF (blocks pacemaker current)

Answer 10

Monitor HR, risk of bradycardia

Question 11

Cimetidine or Spironolactone (type a)

Answer 11

Gynaecomastia

Question 12

NSAIDs (type a)

Answer 12

Asthma caution and GI damage

The biggest burden of ADR. insidious because OTC and abundant. 2000 deaths per year
Prescribe with caution, consider alternative
Who is at risk of GI damage? Co-prescribe a PPI if suspicious

Question 13

Digoxin (type a)

Answer 13

Nausea, vomiting and visual disturbances

Question 14

Cytotoxics (type a)

Answer 14

Myelosuppression

Question 15

beta blockers (type a)

Answer 15

asthma: beta 1 selective, can block beta adrenoreceptors. risk of bronchospasm.
HF + COPD: add beta-1 block brosoprolol for HF, but monitor lung function if they have COPD

Question 16

Describe pharmacokinetic mechanism

Answer 16

Absorption; elimination (renal and hepatic clearance)

Question 17

To avoid an ADR, what key consideration should you make when prescribing digoxin?

Answer 17

renal function

Question 18

How does diazapam’s half-life change with age?

Answer 18

one hour increase per year beyond 20 y/o

Question 19

When should you be cautious in who to prescribe diazepam to?

Answer 19

Neonates; elderly; enzyme defect populations (10% genetic defect to p450 enzyme); hepatic (LFT poorly predicts metabolism)

Question 20

What are type B ADRs?

Answer 20

unpredictable, severe, un-related to pharmacology, rare, genetic or immunological
Respond not by reducing dose, but stopping the medication

Question 21

What is agranulocytosis ? common examples?

Answer 21

Type B ADR; reduction in WBCs (absence of neutrophils, increased susceptibility to mouth ulcers, infections).
Clozapine is a common example. These patients require freq monitoring
Carbimazole
Carbamazepine

Question 22

Thrombocytopaenia?

Answer 22

Bruising, easy bleeding- Type B ADR.

Question 23

Are NSAIDs a risk to people with CV disease?

Answer 23

yes, it can worsen it. This is due to fluid retention, exacerbation of hypertension.
diclofenac is a no no!!!! (when used topically as a skin preparation it is ok)

Question 24

Does NSAIDS increase risk of renal failure?

Answer 24

Yes, reduction of eGFR

Question 25

Statins

Answer 25

Myopathy (actual muscle damage--> rarely, rhabdomylosis--> kidney failure) 'Routinely say that ''it can cause muscle pain, if so, require blood test to see if there's muscle damage''

Question 26

Skin reactions

Answer 26

irritation--> life threatning* *Urticaria Erythematous erruptions: reddening, may resemble measles or maculopapular Toxic epidermal necrolysis: rare but often fatal with blistering and skin peels off Stevens-Johnson syndrome: fever, rash, blisters

Question 27

Sumatriptan

Answer 27

Green blood. Once in a career occurrence

Question 28

Monitor what with ACE-I?

Answer 28

renal function

Question 29

Risk of drug interactions exacerbated by what?

Answer 29

``` Polypharmacy Renal impairment (ageing patient) Drugs with narrow therapeutic window pose greatest problem (lithium, warfarin, digoxin) ``` OTC does not necessarily = safe Drug-food interactions Elicit drugs important to rule out

Question 30

Stomach interactions

Answer 30

tetracycline: binds Fe, calcium in milk. Not absorbed. Avoid taking with dairy products PPIs, antacids, H2 antagonists raise pH, can affect absorption of certain drugs

Question 31

CYP related metabolism

Answer 31

Interaction | Induction or Inhibition

Question 32

Examples of drug induction.. how does this occur?

Answer 32

``` Rifampicin Phenytoin Carbamazepine Alchohol St. John's Wart (weakly effective anti-depressant) ``` Conc of barbiturates, carbamazepine, rifampicin increase metabolism of OCs May take a week or 2 for effect Effect may persist on stopping inducer

Question 33

Example of drug inhibition. How does this occur?

Answer 33

erythromycin / clarithromycin (avoid with simvostatin--> increases in conc, muscle damage) ciclosporin Psoralen (from grape fruit juice) i.e. macrolide + warfarin- patient bleeds, or even h.stroke. Rapid onset : 1-2 days Often reverse quickly on stopping

Question 34

Drugs to avoid with simvostatin

Answer 34

verapamil, diltiazem For amlodipine plus statin: Pravastatin does not interact Use 20mg simvastatin as maximum dose

Question 35

Key counselling point for methotrexate?

Answer 35

Do not self-prescribe with aspirin or NSAIDs: competition for renal elimination, toxicity risk. Also risk of impaired renal perfusion rhuematologists might be happy to co-prescribe becaue they monitor blood count. Drug interactions can be acceptable if carefully monitored

Question 36

Heart failure patient on diuretic are you safe to use ACE-I??

Answer 36

Risk of first dose hypotension: stop diuretic for a few days

Question 37

Another risk of diuretics?

Answer 37

Risk of hypokalaemia: digoxin risk. Take K levels beforehand

Question 38

Asthma and beta-blockers?

Answer 38

Salbutamol's effectivity (B2 agonist) reduced due to beta blocker activity

Question 39

Calcium channel blockers?

Answer 39

Verapamil etc can act on calcium heart channels. Thus using this drug and beta blocker could stop the heart!! Dihydropyridine does not act on Ca channels of heart, limited to smooth muscle Ca channels.

Question 40

Dangers of using Warfarin. Named alternatives

Answer 40

``` Anticoagulant So many interactions: inducers and inhibitor susceptibility INR: monitor (1 in healthy patient, value increases when blood coagulating less). i.e. measure 3 days after prescribing with macrolide, if it increases, reduce warfarin dose. Increased actions lead to bleeding: gastric cerebral haemoptysis blood in faeces blood in urine easy bruising ``` ``` Reasons why it's being used less. eg Rivaroxaban Direct Oral Anticoagulants Factor X inhibitor Fewer interactions No requirement to monitor ```

Question 41

Examples of alcohol interactions

Answer 41

Labels 2 & 4 (avoid if affected or avoid) Mostly CNS depressant / sedating actions enhanced E.g. TCAs, sedating antihistamines, benzodiazepines Few antibiotics actually interact Metronidazole leads to disulfiram-like effect Gastric effects Avoid aspirin containing products for hangover

Question 42

Food interactions

Answer 42

Cranberry juice thought to potentiate warfarin leading to fatalities Grapefuit juice interacts with simvastatin and some Ca-antagonists

Question 43

1. Warfarin and NSAIDs: 2. Warfarin and antibiotics (esp erythromycin and ciprofloxacin): 3. NSAIDs and methotrexate: 4. ACE inhibitors and potassium/potassium sparing diuretics 5. Verapamil and beta-blockers 6. Digoxin and amiodarone: 7. Digoxin and verapamil: 8. Oral contraceptives and certain inducing agents (e.g. rifampicin, carbamazaepine and phenytoin): 9. Statins and macrolides:

Answer 43

1. leading to enhanced bleeding 2. leading to enhanced bleeding 3. leading to methotrexate toxicity 4. : risk of hyperkalaemia 5. : risk of asystole 6. risk of digoxin toxicity 7. risk of digoxin toxicity 8. risk of failure of contraception 9. risk of myopathy