Q11

Describe the mechanism of action of colchicine.
Prompt - Does colchicine have an effect on uric acid?

1 anti-inflammatory effect (binds to tubulin, inhibits WBC migration and phagocytosis)

2 inhibits formation of leukotriene B4

3 No effect on uric acid metabolism

(1 and 3 to pass)

What are the indications and dosage of colchicine?

1 treatment of acute episodes (0.6-1.2 mg 12h until pain reduces or diarrhoea- 8mg fatal)

2 prophylaxis of recurrent episodes (0.6 mg od-tds)

3 (bonus) preventing Mediterranean fever, treating sarcoid arthritis and hepatic cirrhosis


(either 1 or 2 to pass)


Q12

What are the actions of acetazolamide?

Carb anhydrase inhibitor, ciliary body, choroid plexus, prox. renal tubules (plus one organ)
What are the toxic effects of acetazolamide?

PROMPT: Can renal &/or hepatic disease increase the risk of adverse effects?

  • Hyperchloraemic metabolic acidosis
  • Renal stones (PO4, Ca)
  • Renal K+ wasting
  • Drowsiness, parasthesia
  • Increased risk of neurological toxicity with renal failure (reduced renal elimination)

Hepatic encephalopathy in patients with cirrhosis (reduced renal excretion of NI14+)

Pass: At least one


Q13

Name some of the ingredients in over-the- counter preparations that may cause toxicity.

  • ethanol
  • antihistamines
  • salicylates
  • caffeine
  • local anaesthetics
  • sodium
  • sympathomimetics


(3 of 7 to pass)

Give one example.

  • sympathomimetics and Type-1 DM, HT, asthma, hypothyroidism
  • salicylates and children (Reye’s syndrome), PUD, coagulopathies
  • antihistamines, ethanol and drowsiness
  • sympathomimetics and caffeine and agitation, headaches, interstitial nephritis
  • drug interactions

Q14

Describe the mechanism of action of Frusemide.

Na/K/ 2Cl pump, thick ascending limb loop Henle

What effects do they have on renal handling of Ca and Mg ?

Excretes calcium


Q15

How do you classify H1 antagonists?

Sedating/non sedating or 1st/2nd generation

Describe the pharmacodynamics of promethazine?

H1 antagonist Antidopaminergic
Alpha blockade Na channel blockade

Anticholinergic Antiserotinergic

Pass: at least 3

What are the important adverse reactions associated with this drug?

Sedation

Hypotension


Q16

Can you give me an example of a preparation of calcium that is taken orally?

Calcium Carbonate or Ca -acetate, citrate, glubionate, gluconate, lactate or phosphate

Pass: Need to name one

What are the possible uses of oral calcium preparations?

i)             Treatment of hypocalcaemia (eg. in patients with hypoparathyroidism, vit D deficiency, chronic renal disease or malabsorption).

ii)            As an antacid

Pass: hypocalcaemia

What are the potential adverse effects of giving calcium intravenously?

Irritation of the veins.

Cardiac arrhythmias with rapid administration. Hypercalcaemia.

Pass: phlebitis


Q17

By what routes can Olanzapine be administered?

  • Oral (tab or wafer)
  • Parenteral – IMI, Depot IMI

Pass Criteria

  • Bold to pass

Patient arrives with a stab wound to the back of his right thigh. He is agitated. You use Olanzapine to sedate him. What dose, and route would you use in this situation?

  • Give dose (10-20mg), same for each route

Pass Criteria:

  • Reasonable answer

What are the advantages of olanzapine over older 'typical' antipsychotics?

PROMPT – e.g. chlorpromazine.

  • Less hypotension
  • Less tachycardia
  • Less extrapyramidal effect
  • High clinical potency
  • Less effect on prolactin
  • More effective vs negative and positive psychotic symptoms and cognition
  • Multiple routes of administration

Pass Criteria:

  • Bold to pass

What are some of its disadvantages?

PROMPT – what about longer term effects?

  • Anticholinergic effects
  • Lowered seizure threshold
  • Weight gain
  • Diabetes mellitus
  • Hyperlipidaemia
  • Expense

Pass Criteria:

  • 2 disadvantages

Q18

What are the pharmacodynamics of haloperidol?

  • Butyrophenone – high potency D2 receptor effects (dopamine antagonist), high extra-pyramidal side effects, low sedative, low hypotensive, minimal anticholinergic effects, minimal 5-HT and H1 blockade effects

Pass Criteria

  • 2/3 bold 

How does olanzapine differ?

  • Thienobenzodiazepine – less D2 receptor effects, high 5-HT receptor blockade effects, low extrapyramidal effects, medium sedative, low hypotensive and anticholinergic effects, low H1 blockade effects

Pass Criteria:

  • 2/3 bold 

What are the advantages of olanzapine over older 'typical' antipsychotics?

PROMPT – e.g. chlorpromazine.

  • Less hypotension
  • Less tachycardia
  • Less extrapyramidal effect
  • High clinical potency
  • Less effect on prolactin
  • More effective vs negative and positive psychotic symptoms and cognition
  • Multiple routes of administration

Pass Criteria:

  • Bold to pass

What are some of its disadvantages?

PROMPT – what about longer term effects?

  • Anticholinergic effects
  • Lowered seizure threshold
  • Weight gain
  • Diabetes mellitus
  • Hyperlipidaemia
  • Expense

Pass Criteria:

  • 2 disadvantages

Q19

What is drug biotransformation?

  • Drug metabolism to allow drugs to become inactive or by increasing excretion by making them more hydrophilic, or by metabolising them to less active agent.

Pass Criteria:

  • Bold to pass

Describe phase 1 and phase 2 reactions.

  • Phase 1
    • Unmasking functional group (-OH, -NH2, -SH) to become more polar metabolite
    • Includes oxidation, deamination, hydrolysis, reductions
  • Phase 2
    • Conjugation with endogenous substrate to become highly polar conjugate

Pass Criteria:

  • Bold to pass

How is suxamethonium metabolised?

  • Rapid phase 1 hydrolysis by butyrycholinesterase and pseudocholinesterase in liver and plasma

Pass Criteria:

  • One of bold to pass

Why may a patient have a prolonged paralysis following Suxamethonium?

  • Genetically deficient in BCHE so slowed metabolism

Q20

A 30 year old woman who is 35 weeks gestation presents with a severe headache and a BP of 160/100. Her treatment includes magnesium. What are the indications of its use in pregnancy?

  • It is indicated in pre-eclampsia and eclampsia
  • For the prevention and treatment of life threatening seizures

Pass Criteria:

  • Bold to pass

What are the other uses of magnesium in Emergency Medicine?

  • It has an anti-convulsant effect, possible anti-arrhythmic effect, bronchodilator effect (influences Na+/K+-ATPase, sodium channels, certain potassium and calcium channels)

Pass Criteria:

  • 2/3 bold to pass

What are the toxic effects of magnesium?

  • Nausea and vomiting
  • Flushing
  • Hypotension
  • Muscle weakness
  • Muscle paralysis
  • Blurred or double vision
  • CNS depression or loss of reflexes
  • Respiratory depression
  • Renal failure
  • Cardiac arrhythmia

Pass Criteria:

  • 3 to pass

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