Pharma/Tox Flashcards

1
Q

Mechanism of action of bisphosphonates

A

Inhibits osteoclastic activity

Note: no effect on osteoblastic activity

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2
Q

Treatment of beta blocker overdose

A

1st line atropine

2nd line glucagon

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3
Q

Side effects of acetazolamide

A

MOA: inhibition of carbonic anhydrase

Metabolic acidosis (due to bicarb loss in the proximal and distal tubules, by inhibiting reabsorption)
HypoNa
Acute interstitial nephritis
Agranulocytosis and thrombocytopenia

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4
Q

Deafness is a recognised complication of aspirin overdose T/F

A

True

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5
Q

Management of aspirin overdose?

A

Gastric lavage up to 4 hours. Activated charcoal for sustained-release preperations
Plot level at 6 hours on normogram
Alkalisation of urine to aid drug excretion, close monitoring of electrolytes and pH , electrolyte repletion

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6
Q

In aspirin overdose hypoventilation is common T/F

A

False - tachypnea is common.
Note: Phase 1 tachypnea directly stimulates the resp center -> resp alkalosis with a compensatory alkaline urine with bicarb and potassium loss

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7
Q

Aspirin overdose is associated with hypoK and hyopglycaemia T/F

A

True

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8
Q

When is activated charcoal indicated in treatment of paracetamol OD?

A

If >150mg/kg taken + presentation <1 hr since ingestion

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9
Q

Melatonin is primarily metabolised in the kidney T/F

A

F - primarily met in the liver, hence can build up in those with hepatic impairment

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10
Q

The MOA of melatonin is due to binding to MT1 and MT2 receptors T/F

A

True

Note: MT1 is in the suprachiasmatic nucleus of the ant hypothalamus and MT2 is in the retina

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11
Q

Melatonin is C/I in those with epilepsy T/F

A

F - used to be thought to lower sz threshold but that was a poor study

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12
Q

Where is digoxin eliminated?

A

70% is excreted unchanged in the urine

NB: in patients with CKD they should be treated with a decreased loading dose and decreased maintenance dose

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13
Q

Patients on co trimoxazole need to be monitored for what serious (but rare) side effect?

A

Cholestatic jaundice

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14
Q

Code dose adrenaline?

A

0.1mg/kg 1:10,000

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15
Q

What is the most common adverse effect of theophylline overdose?

A

Arrhythmia (it is a phosphodiesterase inhibitor but also acts on adenosine receptors such as on the AV node)

Note: other adverse effects agitation, restlessness or seizure

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16
Q

What is the initial treatment of a TCA overdose?

A

IV sodium bicarbonate

Note: leads to QRS prolongation and possible tachyarhythmias due to Na channel blocking in the myocardium. Na bicarb increases TCA protein binding, dislodges TCA from the Na channel and increased TCA elimination. TCA OD renders the myocardium relatively insensitive to tradition antiarrhythmics.

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17
Q

What class of antidepressant is associated with GI bleeds?

A

SSRI

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18
Q

Doses in adrenaline pens for anaphylaxis?

A

EpiPen Jr 0.15mg (< 6yrs)
EpiPen 0.3mg (6-12 yrs)
IM adrenaline 0.5mg ( >12 yrs)

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19
Q

Indication for activated charcoal in drug overdose?

A

Within 1 hr of ingestion in a conscious patient (N +V are common post treatment so want to avoid in those with altered level of consciousness)

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20
Q

Trimethoprim can cause an elevation in urea and Cr T/F

A

F - only causes elevation in Cr. It completes with Cr for secretion into the renal tubules so causes asymptomatic elevation in serum Cr with no change in urea. This is not true renal injury

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21
Q

Where does cyclizine work?

A

Medulla oblongata

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22
Q

Beta blockers can cause difficulty sleeping/insomnia T/F

A

True

Can also cause hypoglycaemia

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23
Q

Side effect of prostaglandin

A

Apneoa

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24
Q

Treatment of hereditary angio-edema?

A

C1 inhibitor or kallikrein inhibitor ecallantide

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25
Q

Where does methylphenidate work?

A

Basal ganglia - inhibition of dopamine reuptake

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26
Q

Rifampicin reduces the levels of statin T/F

A

T

Clarithromycin increases the levels of statins

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27
Q

Antibiotic that increased the levels of statins?

A

Clarithromycin

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28
Q

Steroids are CI in the treatment of TB meningitis T/F

A

F - they are an adjunct to treatment with triple antiTB therapy

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29
Q

Mechanism of action of ipratropium bromide?

A

Anti muscarine bronchodilator

SE: mydriasis (dilated pupils), skin flushing, hyperthermia, dry skin and mouth, urinary retention and agitation

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30
Q

Usual stat tx dose of oral dex in croup tx?

A

0.15mg/kg

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31
Q

In patients with renal impairment the loading dose of drugs needs to be decreased T/F

A

F - loading doses remain unchanged - loading doses are related to the volume of distribution which remains unchanged.

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32
Q

Conversion of oral morphine to subcut diamorphine and subcut morphine?

A

10mg oral morphine = 3mg diamorphine

10mg oral morphine = 5mg subcut morphine

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33
Q

In the tx of allergic rhinitis when is an oral antihistamine 1st line (instead of intranasal)

A

Oral is first line if:

  • pt 2-5 yrs
  • preference to take oral
  • conjunctivitis is also present
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34
Q

What is the MOA of baclofen?

A

Agonist of GABA beta receptor

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35
Q

What is the MOA of benzos?

A

Increase the potency of GABA at the GABA alpha receptors (AKA +ve allosteric modulator of GABA alpha receptor)

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36
Q

What medications should be avoid in those with Juvenile myoclonic epilepsy?

A

Carbamazepine
Phenytoin
Oxcarbazepine
They can aggravate the sz

Note: sleep deprivation and alcohol consumption can precipitate the sz; EEG will show periodic 3Hz spikes

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37
Q

What is considered a staggered dose of paracetamol? How does this impact treatment?

A

Staggered dose is any dose taken over longer than an hour. At greater than an hour the normogram cannot be used and hence if there is concern that a person has ingested a significant amount they should just be treated with NAC

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38
Q

What is the best steroid to use in a pt who already has HTN?

A

Dexamethasone - has little to no mineralocorticoid activity

Note: methylpred and pred have significant mineralocorticoid activity

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39
Q

What is a Type A drug reaction?

A

“Augmented” - eg hypotension with a beta blocker or hypoglycaemia with insulin

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40
Q

What is a Type B drug reaction?

A

“Bizarre” - anaphylaxis

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41
Q

What is a Type C drug reaction?

A

“Continued” - lasts for a long time, eg visual field defects with vigabatrin

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42
Q

What is a Type D drug reaction?

A

“Delayed” - eg neutropenia with chemo

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43
Q

What is a Type E drug reaction?

A

“End of use” - withdrawal symptoms

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44
Q

MOA of beta lactams?

A

Inhibition cell wall synthesis

Vancomycin also works in this way

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45
Q

MOA of colistin (a polymyxin)

A

Disrupts cell membrane integrity

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46
Q

MOA of co-trimoxazole ?

A

Inhibition of folate synthesis

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47
Q

MOA of quinolones?

A

Inhibition of mRNA synthesis (eg ciprofloxacin)

48
Q

MOA of aminoglycosides?

A

Inhibition of protein synthesis by binding to 30s ribosome subunit

49
Q

Antidote to unfractionated heparin?

A

Protamine

Note: it has limited utility against LMWH

50
Q

How many half lives are needed for the drug to be mostly cleared?

A

5

51
Q

Side effects of montelukast?

A

Common: GI upset and rash
Rare: can precipitate Churg Strauss syndrome (can present with worsening asthma, neuropathy and a peripheral eosinophilia)

52
Q

When should a digoxin level be checked?

A

Anytime more than 6 hours post dose.

53
Q

What antibiotics are C/I in those with myasthenia gravis?

A

Aminoglycosides (such as gentamicin or amikacin) as they cause blockade of the NMJ and can exacerbate the condition

54
Q

What is the preferred opioid to be used for analgesia in a syringe driver?

A

Diamorphine - it has a high solubility that allows a large dose to be given in a small volume (hence more practical than morphine)

55
Q

Inhibition of hypoxanthine-guanine phosphoribosyltransferase what drug?

A

Mercaptopurine

56
Q

Which antibiotics are most strongly associated with c dif/pseudomembranous colitis?

A

Cephalosporins ( eg cephalexin, cefuroxime) is strong

Also common with clindamycin, ampicillin and amoxicillin

57
Q

How does acute Vit A toxicity present?

A

Signs of raised ICP

58
Q

Vincristine can have neurotoxicity side effects T/F

A

True - these can manifest as mobility issues, limb or back pain or cranial nerve neuropathies

Can also cause constipation, change in sensation, headaches

59
Q

What type of drug is levomepromazine?

A

Antiemetic

Note: drowsiness is a side effect

60
Q

Which is a stronger steroid HCT or prednisolone? How to convert HCT to pred

A

Prednisolone

Pred dose is 25% of the total dose of HCT. eg if on 25mg HCT this would be 25mg/4.

61
Q

TB medication that can cause seizures in infant?

A

Isoniazid

62
Q

Hoarse voice is a side effect of inhaled steroid use T/F

A

T - they deposit in the vocal cords leading to change in timbre

63
Q

Coma is a feature of severe salicylate overdose T/F

A

F - can cause delirium or confusion but not typically coma

64
Q

Sweating is a feature of salicylate overdose T/F

A

T - can interfere with the CNS autonomic function and increase basal metabolic rate leading to sweating

65
Q

Common side effect of Efavirenz?

A

Depression (in those with no prior history of mental health problems)

Note: Rilpivirine can cause depression too but it is more likely in those which a hx of mental health problems

66
Q

Common side effect of Rilpivirine?

A

Depression (more likely in those which a hx of mental health problems)

67
Q

Most common side effect of Emtricitabine?

A

Rash and darkening of palms and sole

68
Q

What lab abnormality does Cimetidine cause?

A

Elevation of creatinine without changing real GFR

69
Q

What is the mechanism of cough due to ACE inhibitors?

A

Increased bradykinin

70
Q

When given IV cotrimoxazole should be given as a slow IV bolus or an infusion?

A

As an infusion, preparation is very alkaline and hence can be caustic if given as a bolus

Note: although preferable to give via a central line can be given via a peripheral if it is diluted enough

71
Q

Gentamycin gram + or gram -ve coverage?

A

Gram -ve only

72
Q

Typical anticholinergic side effects?

A

Tachycardia
Pupil dilatation (mydriasis)
Dry mucus membranes
Urinary retention

73
Q

HypoNa is MDMA ingestion can be due to SIADH

A

True - can also be due to excessive fluid intake

74
Q

HypoNa is the most common cause of death in MDMA overdose T/F

A

F - arrhythmia is most common

75
Q

What are indications for hyperbaric O2 in carbon monoxide poisoning?

A
  1. CV dysfxn
  2. Pregnant (esp if carboxyHb >10%)
  3. CarboxyHb > 20%
  4. Unconscious / episode of syncope
  5. Neuro/psych features (excluding HA)
76
Q

Is bradycardia a characteristic feature of opioid overdose?

A

Yes

77
Q

2 drugs that can cause hyperventilation in overdose?

A

Theophyline

Salicylates

78
Q

LSD is associated with serotonin syndrome T/F

A

F - LSD is not

Note: MDMA is assoc with serotonin syndrome

79
Q

Typical features of serotonin syndrome?

A
Sweating
Agitation
Tachycardia
Dilated pupils
Muscle rigidity 
In severe cases: seizures, clonus
80
Q

Mechanism of action of loop diuretic is on the Na-K-Cl co transporter or the Na-Cl symporter

A

Na-K-Cl co transporter

81
Q

Mechanism of action of thiazide diuretic is on the Na-K-Cl co transporter or the Na-Cl symporter

A

Na-Cl symporter

82
Q

Seizures occur in about 50% of patients presenting with an NSAID overdose T/F

A

F - occurs in about 10-20%. It is more common in patients who have taken mefenamic acid

83
Q

What are the main side effects of NSAID overdose?

A

Common: mild GI - epigastric tenderness, nausea, emesis and diarrhoea (due to inhibition of cycle-oxygenase mostly)
Large overdoses can also have drowsiness, coma , cerebellar signs and seizures. AKI and cardiorespiratory arrest, hypothrombinaemia

84
Q

Desferrioxamine IV is a chelator used for what type of poisoning?

A

Significant iron overdose

85
Q

Common side effects of cyclosporin?

A

Chronic interstitial nephritis
Hypertrichosis
Gum hypertrophy

Note: phenytoin also causes gum hypertrophy

86
Q

In a patient starting on MTX NSAIDs use should be avoided, why?

A

NSAIDs can result in AKI or just mildly decreased kidney function. MTX relies on renal excretion and hence even a small decrease in kidney function can result in increased toxicity

87
Q

In terms of teratogenic effects thalidomide causes phocomelia T/F

A

T - aka abnormalities of the limbs

88
Q

What drug is known to cause chondrodysplasia punctata in the foetus?

A

Warfarin - these are skeletal abnormalities with punctate calcification of the cartilage of the epiphyses, larynx and trachea

89
Q

What is the MOA of bosentan?

A

Endothelin receptor antagonist

Nore: endothelin is a potent vasoconstrictor, it is a polypeptide

90
Q

What TB drug is known to cause red/orange discolouration of bodily fluids?

A

Rifampacin

91
Q

What HIV medications are closely associated with fat loss/lipoatrophy?

A

Zidovudine, stavudine (nucleoside RTIs)

92
Q

How should amiodarone be administered to a neonate

A

IV (ideally via a central line) diluted in 5% glucose

Note: it is incompatible with NaCl ; needs to be diluted as it is alkaline and can cause pain and inflammation on infusion if not
Oral abs in the neonatal period is unpredictable and in general abs is very slow

93
Q

What labs are the best markers of severity in paracetamol overdose?

A

INR
pH
Serum Creatinine

94
Q

What is the mechanism of action of terlipressin?

A

Vasopressin analogue - hence causes vasoconstriction of the splanchnic blood vessels.

95
Q

What is the mechanism of action of activated charcoal in treatment of drug overdose?

A

Interrupts a drug’s enterohepatic circulation

96
Q

What is the main reaction involved in the normal metabolism of paracetamol?

A

Glucuronidation

Note: when this pathway becomes overwhelmed in overdose cyto p450 pathway is used

97
Q

What is the appropriate mgmt of a patient with an elevated gent trough and why?

A
trough = renal clearance
peak = drug dose

–> keep dosing the same but less often so as to allow drug to still reach therapeutic peak and also give enough time to clear

98
Q

What is a good inotrope to use if you do not want to increase HR?

A

Phenylephrine as it is purely alpha adrenergic and hence raises BP without effect on HR

99
Q

What is the mechanism of action of dobutamine?

A

Pure beta 1 adrenergic –> increases HR and force of contraction

Note: good for cardiogenic shock

100
Q

Why should codeine be used with caution in those < 6 yrs old/avoided if possible?

A

It metabolises v quickly to morphine

101
Q

Which atypical antipsychotic has particularly high likelihood to cause the side effect of hyperprolactinaemia?

A

Risperidone

102
Q

Statins block de novo cholesterol synthesis T/F

A

T - hmg CoA reductase inhibitor

103
Q

What is the MOA of sildenafil?

A

Inhibits breakdown of cGMP (guanosine monophosphate) –> increasing cGMP

104
Q

How does glucagon function in treatment of beta blocker overdose?

A

Increases cAMP (adenosine monophosphate) by direct stimulation of adenylate cyclase in the cardiac mycytes –> increasing rate and force of cardiac contraction

Note: mode of action is independent of the blocked beta receptors

105
Q

What is the MOA of aminophylline and theophylline?

A

Phosphodiesterase inhibitor and adenosine antagonist

106
Q

Leucopenia is a side effect of lithium T/F

A

F - leucocytosis

107
Q

Leucocytosis is a side effect of lithium T/F

A

T

108
Q

Acetazolamide can cause what acid base abnormality?

A

Met acidosis

Note: loop, thiazides cause alkalosis

109
Q

Paracetamol is a non selective inhibitor of COX1 and 2 enzymes. T/F

A

F - inhibits cox 1 –> resulting in reduced prostaglandin synthesis

110
Q

Dosing of mannitol and hypertonic saline for treatment of cerebral oedema

A

Mannitol 1g/kg (20%)
2.5 -5ml/kg hypertonic saline

Both over 10-15 minutes

111
Q

On what cells do PPIs work?

A

Parietal cells

Blocks the H/K ATP pump

112
Q

Where does mannitol act?

A

Entire loop of henle

113
Q

For a child weighing 35kg the dose of NAC is 150mg/kg in 100ml 5% glucose T/F

A

T - for a child weighing 20-39kg this is the dose

114
Q

For a child weighing 10kg what is the dose of NAC

A

150mg/kg in 3ml 5% glucose

This is the dose for a child < 20 kg

115
Q

For a child weighing 45kg the dose of NAC is 150mg/kg in 100ml 5% glucose T/F

A

F - the NAC should be in 200ml, this is the dosing for anyone > 40kg (adult dosing)

116
Q

NAC works in paracetamol overdose by reducing the formation or the circulation of toxic metabolites?

A

It reduces the circulation

117
Q

Gum hypertrophy is a side effect of nifedipine T/F

A

T