Pharmacology - Corrections Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is the correct rate of infusion of N-acetylcysteine in a paracetamol overdose?

A

IV N-acetylcysteine over 1 hour

Acetylcysteine is a common cause of anaphylactic reactions, generally managed with slower infusions (i.e. this rate reduces risk of adverse effects).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What class of drug is doxazocin?

A

Alpha blocker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Give 2 examples of alpha blockers

A

1) tamsulosin
2) doxazosin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What medications may precipitate lithium toxicity?

A

1) diuretics (especially thiazides)
2) ACEi/ARBs
3) NSAIDs
4) metronidazole.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can NSAIDs predispose to lithium toxicity?

A

NSAIDs can cause renal impairment by decreasing prostaglandin synthesis –> decreases in glomerular filtration rate. There is evidence that these drugs can increase lithium levels and decrease renal lithium clearance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the appropriate dose of IM adrenaline in anaphylaxis?

A

0.5mg - 0.5ml 1:1000 IM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which drugs should be AVOIDED in renal failure?

A

1) Abx: tetracycline, nitrofurantoin

2) NSAIDs

3) lithium

4) metformin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which drugs are likely to accumulate in chronic kidney disease so will need dose adjustment?

A
  • most antibiotics including penicillins, cephalosporins, vancomycin, gentamicin, streptomycin
  • digoxin, atenolol
  • methotrexate
  • sulphonylureas
  • furosemide
  • opioids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Tinnitus is an early symptom of an overdose of what?

A

Salicylates e.g. aspirin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Who is at risk of lactic acidosis from metformin?

A

Patients with severe liver or renal failure.

Review dose in patients with eGFR <45 and STOP in <30.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What monitoring investigations are required in patients on amiodarone?

A

TFTs & LFTs every 6 months

CXR prior to starting treatment (but not routinely)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is G6PD deficiency?

A

An X-linked recessive disorder that causes a defect in the red cell enzyme glucose-6-phosphate dehydrogenase.

This deficiency leads to intravascular haemolysis which can be triggered by the ingestion of certain drugs and foods (including fava (broad) beans).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What drugs are contraindicated in G6PD deficiency?

A

Drugs that can precipitate haemolysis:

  • antimalarials
  • ciprofloxaciin
  • sulphonamides (including co-trimoxazole)
  • sulphonylureas
  • sulphasalazine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are quinolones?

Give 2 examples

A

A group of Abx that work by inhibiting DNA synthesis and are bactericidal in nature.

  • ciprofloxacin
  • levofloxacin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Adverse effects of quinolones?

A
  • lower seizure threshold in patients with epilepsy
  • tendon damage (including rupture) - the risk is increased in patients also taking steroids
  • cartilage damage has been demonstrated in animal models and for this reason quinolones are generally avoided (but not necessarily contraindicated) in children
  • lengthens QT interval
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 4 key drugs used in the management of TB?

A

Rifampicin
Isoniazid
Pyrazinamide
Ethambutol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the most common side effects of rifampicin?

A
  • orange bodily fluids
  • rash
  • hepatotoxicity
  • enzyme inducer (drug interactions)
  • flu like symptoms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the most common side effects of Isoniazid?

A
  • peripheral neuropathy
  • psychosis
  • hepatotoxicity
  • agranulocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can peripheral neuropathy as a result of isoniazid be prevented?

A

With pyridoxine (vitamin B6)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the most common side effects of pyrazinamide?

A
  • arthralgia & myalgia
  • gout (due to hyperuricaemia)
  • hepatotoxicity
  • nausea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the most common side effects of ethambutol?

A
  • optic neuritis (check visual acuity before and during treatment)
  • rash
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

If women take HRT for premature menopause, how long should it be continued for?

A

Until age of 50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Define premature menopause

A

Ovarian failure occurring before the age of 40.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the most important reason in giving HRT to women with premature menopause?

A

Preventing development of osteoporosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Contraindications for metformin?

A

1) CKD: stop if creatinine >150 or eGFR <30

2) Can cause lactic acidosis if taken during a period where there is tissue hypoxia e.g. recent MI, sepsis, AKI and severe dehydration

3) Iodine-containing x-ray contrast media e.g. coronary angiography

4) Alcohol abuse is a relative contraindication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why is metformin contraindicated in coronary angiography?

A

There is an increasing risk of provoking renal impairment due to contrast nephropathy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

When should metformin be stopped prior to coronary angiography?

A

On day of procedure and for 48 hours afterwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What class of medication is amiloride?

A

Potassium sparing diuretic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which TB medication can cause gout?

A

Pyrazinamide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the mechanism of action of unfractionated heparin?

A

Activates antithrombin III.

This in turn inhibits thrombin and factors Xa, Ixa, XIa and XIIa.

This stops fibrin formation and thrombin from activating factors V, VIII, and XI.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the treatment for adrenaline induced ischaemia?

A

Phentolamine

This drug is a competitive α-adrenoreceptor antagonist which can be injected to reverse the effects of adrenaline on the vasculature.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the features of salicylate poisoning (e.g. aspirin)?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What type of acid base disorder does salicylate poisoning lead to?

A

Leds to a mixed respiratory alkalosis and metabolic acidosis

Early stimulation of the respiratory centre leads to a respiratory alkalosis whilst later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis.

Note - In children metabolic acidosis tends to predominate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Features of salicylate overdose?

A
  • hyperventilation (centrally stimulates respiration)
  • tinnitus
  • lethargy
  • sweating, pyrexia
  • N&V
  • hyperglycaemia and hypoglycaemia
  • seizures
  • coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Treatment of salicylate overdose?

A

1) general (ABCDE, charcoal)

2) urinary alkalinisation with intravenous sodium bicarbonate - enhances elimination of aspirin in the urine

3) haemodialysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Give some indications for haemodialysis in salicylate overdose

A

1) serum concentration > 700mg/L

2) metabolic acidosis resistant to treatment

3) acute renal failure

4) pulmonary oedema

5) seizures

6) coma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Why should ciprofloxacin be avoided in epilepsy?

A

As ciprofloxacin lowers the seizure threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the key effect of organophosphate insecticide poisoning?

A

The inhibition of acetylcholinesterase leading to upregulation of nicotinic and muscarinic cholinergic neurotransmission.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are the features of organophosphate poisoning the result of?

A

Accumulation of acetylcholine (due to inhibition of acetylcholinesterase).

40
Q

Give some features of organophosphate poisoning.

Mneumonic: SLUD

A

S - Salivation
L - Lacrimation
U - Urination
D - Defecation/diarrhoea

Others:
- hypotension, bradycardia
- small pupils
- fasciculations

41
Q

What is the mainstay of management of organophosphate poisoning?

A

Atropine

42
Q

Give 2 examples of tetracyclines Abx

A

1) doxycycline
2) tetracycline

43
Q

Mechanism of tetracyclines?

A

protein synthesis inhibitors

44
Q

Give 4 indications for tetracycliines?

A
  • acne vulgaris
  • Lyme disease
  • Chlamydia
  • Mycoplasma pneumoniae
45
Q

What are some notable adverse effects of tetracyclines?

A

1) discolouration of teeth (avoid in children <12)

2) photosensitivity

3) angiodema

4) black hairy tongue

Note - avoid in pregnancy & BF due to the risk of discolouration of the infant’s teeth.

46
Q

Why are tetracyclines avoided in children <12?

A

Due to risk of discolouration of teeth

47
Q

Give some causes of drug induced photosensitivity

A
  • thiazides
  • tetracyclines, sulphonamides, ciprofloxacin
  • amiodarone
  • sulphonylureas
  • NSAIDs e.g. piroxicam
48
Q

Which 3 Abx can cause photosensitivity?

A
  • tetracyclines
  • sulphonamides
  • ciprofloxacin
49
Q

What class of medication is used in the treatment of erectile dysfunction?

A

Phosphodiesterase type V (PDE5) inhibitors

50
Q

What are the 2 indications for PDE-5 inhibitors?

A

1) ED

2) Pulmonary HTN

51
Q

How do PDE-5 inhibitors work in ED?

A

Cause vasodilation through an increase in cGMP, leading to smooth muscle relaxation in blood vessels supplying the corpus cavernosum.

52
Q

What is the main example of a PDE-5 inhibitor?

A

sildenafil (Viagra)

53
Q

Give 3 contraindications of sildenafil/PDE-5 inhibitors?

A

1) patients taking nitrates and related drugs such as nicorandil

2) hypotension

3) recent stroke or MI (NICE recommend waiting 6 months)

54
Q

Give some side effects of PDE-5 inhibitors (e.g. sildenafil)?

A
  • visual disturbances e.g. blue discolouration
  • nasal congestion
  • flushing
  • GI side effects
  • priapism
  • headache
55
Q

Which drug used in the management of tuberculosis is most associated with peripheral neuropathy?

A

Isoniazid

56
Q

What are some precipitating factors for lithium toxicity

A
  • dehydration
  • renal failure
  • drugs: diuretics (especially thiazides), ACE inhibitors/angiotensin II receptor blockers, NSAIDs and metronidazole.
57
Q

What are the key drugs that can cause lithium toxicity?

A
  • diuretics (especially thiazides)
  • ACEi/ARBs
  • NSAIDs
  • metronidazole
58
Q

What are some features of lithium toxicity?

A
  • coarse tremor (a fine tremor is seen in therapeutic levels)
  • hyperreflexia
  • acute confusion
  • polyuria
  • seizure
  • coma
59
Q

Management of lithium toxicity?

A

1) mild-moderate toxicity may respond to volume resuscitation with normal saline

2) haemodialysis may be needed in severe toxicity

60
Q

If metformin is not tolerated due to GI side-effects, what is next step?

A

try a modified-release formulation before switching to a second-line agent

61
Q

What is the most appropriate time to take blood samples for therapeutic monitoring of lithium levels?

A

12 hours after last dose

62
Q

Give some drugs that should be avoided in renal failure?

A
  • Abx: tetracycline, nitrofurantoin
  • NSAIDs
  • lithium
  • metformin
63
Q

What are the 2 main indications for HRT?

A

1) vasomotor symptoms such as flushing, insomnia and headaches

2) premature menopause

64
Q

What are the 2 routes of HRT?

A

Orally & transdermally (via a patch or gel)

65
Q

What type of HRT is preferred if the woman is at risk of VTE?

A

Transdermal HRT

66
Q

Mechanism of UH vs LMWH?

A

Heparins generally act by activating antithrombin III.

UH –> forms a complex which inhibits thrombin, factors Xa, IXa, XIa and XIIa

LMWH –> only increases the action of antithrombin III on factor Xa

67
Q

What are 4 key adverse effects of heparin?

A

1) bleeding
2) thrombocytopenia
3) osteoporosis & increased risk of fractures
4) hyperkalaemia

68
Q

How do heparins cause hyperkalaemia?

A

this is thought to be caused by inhibition of aldosterone secretion

69
Q

Route of administration of UH vs LMWH?

A

UH - IV

LMWH - SC

70
Q

Duration of action of UH vs LMWH?

A

UH - short

LMWH - long

71
Q

Which type of heparin has a higher risk of heparin-induced thrombocytopaenia (HIT) & osteoporosis?

A

UH

72
Q

What is heparin induced thrombocytopenia (HIT)?

A

Immune mediated - antibodies form against complexes of platelet factor 4 (PF4) and heparin.

This results in platelet activation and eventually thrombocytopenia.

73
Q

When does HIT typically occur?

A

5-10 days after treatment

74
Q

What is the key complication of HIT?

A

Despite being associated with low platelets HIT is actually a prothrombotic condition.

75
Q

Features of HIT?

A
  • 50% reduction in platelets
  • thrombosis
  • skin allergy
76
Q

What is the 1st line treatment for severe digoxin toxicity?

A

Digibind

77
Q

Features of digoxin toxicity?

A
  • generally unwell, lethargy, nausea & vomiting
  • anorexia
  • confusion
  • yellow-green vision
  • arrhythmias (e.g. AV block, bradycardia)
  • gynaecomastia
78
Q

What is the classical precipitating factor for digoxin toxicity?

A

Hypokalaemia

79
Q

How does hypokalaemia predispose to digoxin toxicity?

A

Digoxin normally binds to the ATPase pump on the same site as potassium.

Hypokalaemia → digoxin more easily bind to the ATPase pump → increased inhibitory effects.

80
Q

What diuretics can cause lithium toxicity?

A

Thiazides

81
Q

Give 4 drugs that commonly cause urticaria

A

1) aspirin
2) penicillins
3) NSAIDs
4) opiates

82
Q

What is an oculogyric crisis?

A

A dystonic reaction to certain drugs or medical conditions.

It causes restlessness, agitation and involuntary upward deviation of the eyes.

83
Q

Give 3 causes of an oculogyric crisis

A

1) antipsychotics (typically 1st generation/typical)

2) metoclopramide

3) postencephalitic Parkinson’s disease

84
Q

Mainstay of management of an oculogyric crisis?

A

1) Cessation of causative medication if possible

2) IV antimuscarinic –> benztropine or procyclidine

85
Q

Which 2 TCAs are particularly dangerous in overdose?

A

Amitriptyline & dosulepin

86
Q

What are some features of TCA overdose?

A

Early –> dry mouth, dilated pupils, agitation, sinus tachycardia, blurred vision (relate to anticholinergic properties)

Features of severe poisoning include:
- arrhythmias
- seizures
- metabolic acidosis
- coma

87
Q

ECG changes in TCA overdose?

A
  • sinus tachycardia
  • widening of QRS
  • prolongation of QT interval
88
Q

How oes TCA overdose affect QT interval?

A

prolongation of QT interval

89
Q

How oes TCA overdose affect QRS complex?

A

widening of QRS

90
Q

What are the dangers of QRS widening?

A

Widening of QRS > 100ms: associated with an increased risk of seizures

QRS > 160ms: associated with ventricular arrhythmias

91
Q

What is the 1st line therapy of TCA overdose?

A

IV bicarbonate

Indications include widening of the QRS interval >100 msec or a ventricular arrhythmia.

92
Q

Mechanism of aspirin to achieve an antiplatelet effect?

A

1) irreversibly inhibits cyclooxygenase-1 (COX-1) enzyme

2) this prevents the conversion of arachidonic acid to thromboxane A2 (a potent vasoconstrictor and platelet aggregator)

93
Q

What Abx are contraindicated in pregnancy?

A
  • tetracyclines
  • aminoglycosides
  • sulphonamides and trimethoprim
  • quinolones
94
Q

Why should cyclizine be used with caution in heart failure?

A

Cyclizine is a H1-receptor antagonist that acts by blocking histamine receptors in the CTZ.

Cyclizine can cause a drop in cardiac output and an increase in heart rate. For this reason, caution should be employed in patients with severe heart failure.

95
Q

What class of drug is doxazosin?

A

Alpha blocker

96
Q

What carboxyhaemoglobin (COHb) level in smokers is normal?

A

Smokers tend to have an increased COHb level - anything up to 10% is considered normal in a smoker.

So in carbon monoxide poisoning we would expect the COHb to be at least above 10%.

97
Q
A