Pharmacology Flashcards

1
Q

Patients on long term steroid therapy, due to to operation.
What to do with steroids?

A

If already receiving therapeutic dose (e.g. for COPD, asthma, rheumatoid arthritis)
—> Continue with the usual daily dose

If on physiologic replacement doses (e.g. for Addison’s disease)
—> Should receive additional 50mg of hydrocortisone intraoperatively

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2
Q

Contraindications to use nitrates

A
  • SBP < 90mmHg
  • HR < 50bpm or > 100 bpm
  • Known right ventricular infarction
  • Severe aortic stenosis
  • Hypertrophic cardiomyopathy

Can lead to cardiac decompensation and haemodynamic instability

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3
Q

Sulphonylureas
Mechanism of action

A
  • most wifely used drugs for T2DM
  • gliclazide, glimepiride, glipizide
  • stimulates pancreatic beta cells and causes secretion of insulin
  • may also have extrapancreatic effects — increases tissue sensitivity to insulin (minimal effects though)
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4
Q

Best initial treatment of Parkinson’s disease

What to do when overstimulated?

A

Carbidopa/levodopa
- may develop dyskinesia after a few months
- due to overstimulation of dopamine receptors
- so must reduce the dose without loss of therapeutic efficacy
- alternative/can be added if cannot achieve: amantadine, pergolide

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5
Q

What antiepileptic drugs induces liver enzymes?

Side effects of these drugs on pregnant women?

What do to with women who are on antiepileptics and require OCPs?

A

Carbamazepine, phenytoin, barbiturates (phenobarbital), topiramates

High risk of teratogenicity: cleft lip or palate, cardiac anomalies, neural tube defects and hypospadias

RACGP: OCP with high estrogen content (Microgynon 50) should be used to minimise the risk of “pill failure”
If possible, ++ barrier method with condom.
[Not even progesterone-only pills should be used]

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6
Q

Gentamicin ~ botulism

A

Gentamicin
- prevents the release of acetylcholine from nerve endings like botulinum toxin
- can cause muscle paralysis in high risk patients
- if eliminate drug, symptoms subsides rapidly
- best avoided in those with pre-existing disturbance to neuromuscular transmission (myasthenia gravis)

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7
Q

Treatment for essential tremor

A

Propranolol or primidone

However, propranolol should be avoided in those contraindicated to BB (such as severe asthma)

If above fails benzodiazepines can be considered in low doses.

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8
Q

Under what circumstances can a patient continue to take hypnotics (such as temazepam or zolpidem etc) for more than 6 months or even years?

A
  1. Patient must be aware that they are dependent on that specific hypnotics
  2. No history of any adverse event/side effects from said medication
  3. Reduction program has been unsuccessful

If plan to stop, stop it gradually, not abruptly.

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9
Q

ECG of Digitalis Toxicity

A
  1. ST depression and T wave inversion in V5-V6 in reversed tick pattern
  2. Bradycardia
  3. Prolonged PR
  4. Shortened QT
  5. Arrhythmias, especially heart block or bigeminy
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10
Q

POP is not a reliable contraception in women taking enzyme-inducing antiepileptic drugs
There is one exception - which drug is it?

A

Sodium Valproate

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11
Q

Most prominent ECG abnormalities in tricyclic antidepressant (amitriptyline) overdose

A
  • WIDENED QRS INTERVAL

Others:
- Prolonged PR and QT intervals
- VT/VF (4% of cases)
- Sinus tachycardia (anticholinergic effect and reflex tachycardia due to haemodynamic decompensation)

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12
Q

Most common cause of false positive elevation of plasma normetanephrine and norepinephrine level in those suspected to have phaeochromocytoma?

A

Tricyclic Antidepressants and Phenoxybenzamine
- 45% of the cases
- Fasting urinary metanephrines should be checked after stopping counfounding drugs

Other causes:
- Congestive cardiac failure
- Major depression
- Panic disorder

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13
Q

INR 5-9, no evidence of significant bleeding, what to do with warfarin?

A

Stop warfarin, give oral or IM vitamin K and check INR in 24H

If significant bleeding occurs before next blood taking, give urgent prothrombinex VF or FFP

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14
Q

INR 5-9
What constitutes clinically significant bleeding requiring immediate reversal of INR?

A
  • intracranial bleeding
  • retroperitoneum bleeding
  • intraocular bleeding
  • muscle bleed with compartment syndrome
  • pericardial bleed
  • active bleed with hypotension or 2g fall in haemoglobin
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15
Q

What PSY drugs are likely to cause alopecia or hair loss?

A

Lithium
Valproate
Carbamazepine
Phenytoin

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16
Q

How long it takes to see therapeutic effects of IV Vitamin K1 (Phytomenadione)?

A

6-8 Hours

Oral takes longer.

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17
Q

Combination of gabapentin and amoxicillin can cause…

A

Hepatotoxicity

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18
Q

Earliest sign of dose-related toxicity of carbamazepine

A

Diplopia, observed within 60 minutes after the morning dose

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19
Q

Donepezil

Contraindications

A

Donepezil
- anticholinesterase drug (decrease breakdown of acetylcholine)
- reduces apparent deficiency of cholinergic neurotransmitter activity in Alzheimer’s disease
- improves alertness and function, maintains cognitive scores for up to 12 months
- must do ECG TRO heart block of bradycardia before starting

Contraindications
- GI or ureteric obstruction
- active peptic ulcer
- heart block
- Bradyarrhythmias (including sick sinus syndrome)
- COPD
- Parkinson’s disease

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20
Q

Raloxifene

A
  • Selective oestrogen receptor modulator (SERM)
  • prevents postmenopausal bone loss
  • reduces risk of vertebral fractures (not non-vertebral)
  • reduces risk of breast CA
  • hot flushes
  • increases risk of DVT

Maximum dose is 60mg
If failed, do not combine with another osteoporosis treatment (not recommended)

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21
Q

What group of antibiotics increases risk of ligament rupture?

A

Fluoroquinolone (e.g. Ciprofloxacin)

[Case: Male over 40 years old, on ciprofloxacin, acute pain and loss of function of posterior aspect of the lower leg, rupture of Achilles tendon]

22
Q

Proton Pump Inhibitor (such as Omeprazole)
Mechanism of action

A
  • profoundly reduces acid secretion in the stomach by up to 99%
  • irreversibly blocks the hydrogen-potassium ATPase enzyme system in the gastric parietal cells

[Case: Cimetadine (antihistamine on H2 receptor), on the other hand, has reversible blockage]

23
Q

Contraindications to Warfarin

A
  • Active bleeding
  • Uncontrolled hypertension
  • History of intracranial bleeding
  • Liver disease with impaired synthetic functions
  • Pregnancy
24
Q

Acute side effects with a course of prednisolone
(Short list)

A

Hyperglycaemia
Hypertension
Fluid retention
Myopathy
Psychological disturbances

25
Q

Drugs that can antagonise cholinesterase inhibitors (Donepezil, galantine and rivastigmine)

A

Drugs with anticholinergic activity (amitriptyline, promethazine, oxybutynin)

26
Q

Anticholinergic Drugs VS Acetylcholinesterase Inhibitors (ACHEIs)

A

Anticholinergic Drugs
- block the transmission of acetylcholine in the central and peripheral nervous system

Acetylcholinesterase Inhibitors (ACHEIs)
- increase availability of acetylcholine by blocking the enzyme (acetylcholinesterase) that breaks it down

27
Q

Adenosine

A
  • Treatment of choice for paroxysmal SVT
  • blocks transmission through AV nodes
  • Short half life: 10-15 SECONDS
  • Contraindicated in patients with asthma, WPW etc
28
Q

Antidote for heparin

A

Protamine sulphate

If active bleeding, use FFP

29
Q

What common analgesic causes premature closure of the fetal ductus arteriosus?

A

NSAIDS is safe to use up to 32 weeks.

After 32 weeks, risk:
- premature closure of the fetal ductus arteriosus
- delay labour and birth
- oligohydramnios via an effect on fetal renal function

30
Q

Osteonecrosis of the jaw

A

IV BISPHOSPHONATES (alendronate, zoledronic acid, risedronate)
(Rarely seen with oral route bisphosphonates)

31
Q

Side Effects of Tricyclic Antidepressants

A

Anticholinergic and Non-Cholinergic side effects:

  • Dry mouth
  • Sedation
  • Confusion
  • Delirium
  • Urinary retention
  • Glaucoma
  • Tremors
  • Weight gain
  • Postural hypotension
  • Sexual dysfunction
  • Lowered seizure threshold

Anticholinergic Toxidrome:
Mad as a Hatter
Blind as a Bat
Dry as a Bone
Red as a Beat
Hot as a Dessert
- absent bowel sounds, tachycardia, shaking, grabbing invisible objects, shaking, dilated pupils (mydriasis)

32
Q

Anticholinergic Toxidrome

A

Mad as a Hatter
Blind as a Bat
Dry as a Bone
Red as a Beat
Hot as a Dessert
- absent bowel sounds, tachycardia, shaking, grabbing invisible objects, shaking, dilated pupils (mydriasis)

33
Q

Theophylline
- oral bronchodilator
- for asthma and COPD
- well absorbed

What increases clearance from liver? (Good thing?)

A
  • Ethanol
  • Smoking
  • High protein
  • BBQ meat
  • low carbohydrate diet

(So you would want to avoid high carb diet)

34
Q

What does fibrates (such as gemfribrozil) do to warfarin?

A

+ increase warfarin’s anticoagulation effect
+ increase risk of bleeding

So must monitor INR and decrease warfarin dose

35
Q

Bosentan (Tracleer)
Mechanism of action

A

Dual endothelin-receptor antagonist
- for treatment of pulmonary artery hypertension

  • Competes against ET-A and ET-B which causes pulmonary vasoconstriction.
  • By blocking interaction, decreases pulmonary vascular resistance
  • higher affinity than ET-A and ET-B
36
Q

Flucloxacillin
Side effects especially in older patients

A

Severe hepatitis and cholestatic jaundice
- especially in older patients and on prolonged periods
- on long term prescription —> must do weekly blood test to monitor LFT

37
Q

Cefepime
- 4th generation cephalosporin

Used for?
Caveat?

A

Used to treat neutropenic fever, healthcare-associated fever and severe CAP
- particularly Pseudomonas aeruginosa

Caveat:
- neurotoxicity especially in older patient with compromised renal function
- delirium, encephalopathy, myoclonus
- EEG: nonconvulsive status epilepticus

38
Q

Contraindications to progesterone-only contraceptive pills

A
  • Severe active liver disease
  • malabsorption syndromes
  • undiagnosed vaginal bleeding
  • previous ectopic pregnancy
  • previous sex steroid-dependent cancers
39
Q

How many days before sugery should a patient with high risk of thromboembolism alreayd on warfarin stop his warfarin?

If INR is > 5-9?

A

Traditionally, 5 days.
Check INR the next day + daily.
Anytime < 2, can start bridging with heparin.

INR has to be < 1.5 to proceed with surgery.
If the day before still > 1.5, can give IV Vit K1 3mg, and repear INR the next day.

However, any time it is > 5-9, without any evidence of bleeding, cease heparin/warfarin, give IV Vit K1 and repear INR the next day.

40
Q

Prothrombinex-VF vs FFP

Which one is preferred for emergencies or ongoing bleeding?

A

If both options are available, Prothrombinex-VF is more desirable, as FFP is more “troublesome”.

Both must be given with IV Vit K1 dose.

41
Q

What are the clinical benefits of beta blockers to the patient with heart failure when used in combination with ACE-I?

A
  • Prevent hospitalisation
  • Prolong life
  • Reverse the process of LV remodelling
  • Block he sustained activation of beta adrenergic receptors (alpha-1, beta-1, beta-2)
  • Improve the patient symptoms
42
Q

Tetracycline: Minocycline, Doxycycline, Tetracycline — are oral antibiotics used to treat Acne Vulgaris

What are the long term side effects of long-term minocycline therapy?

A
  • Dental staining
  • Severe photosensitivity
  • Discolouration of the skin
  • Pneumonitis
  • Serum sickness
  • Autoimmune hepatitis
43
Q

Bisphosphonates

A
  • Slows down bone loss, improve BMD, reduce fracture rates
  • First line treatment of both osteoporosis and prevention of osteoporosis in postmenopausal women
  • Should be continued for at least 5-7 years, with a review of BMD response every 1-2 years
44
Q

Which drugs can cause pinpoint pupils?

A

[Common in those post surgery (opioids and barbiturates)]

  1. Structural pons disease
  2. Opiates (heroin and morphine)
  3. Barbiturates
  4. Organophosphates
  5. Clonidine
  6. Pilocarpine eye drops (parasympathomimetic alkaloid)
45
Q

Haloperidol

Pinpoint pupils or mydriasis?

A

Antipsychotics medication — Mydriasis

46
Q

Xanthine Oxidase Inhibitors are first line urate-lowering drugs. (Allopurinol)
- They decrease uric acid level and prevent gout attacks

What are their indications and contraindications?

A

Absolute indications
- Damage due to chronic gout seen on imaging
- Tophi development
- Frequent gout attacks (≥ 2 per year)
- Serum uric acid > 9 mg/dL on first presentation
- History of urolithiasis (urate kidney stones due to hyperuricaemia)

Contraindications
- Acute gout flare
- Advanced renal impairment — possible but require dosage adjustment — Must maintain U/O 2L/day + avoid the formation of xanthine calculi

47
Q

Vitamin K antagonist = Warfarin

  • used in the treatment of Anti-Phospholipid Syndrome (APS)
A
  • used for the prevented of VTE
  • depresses factor 7, 9, 10 and prothrombin in the blood
  • INR reflects the warfarin dose given 48 hours earlier
  • Thrombosis in APS is one of the indications to use warfarin
  • contraindicated in pregnancy
48
Q

[Case with underlying issues + acute gout]

Verapamil and NSAIDS

ACE-I and NSAIDS

Diuretic (Frusemide) and Gout

A

Verapamil and NSAIDS
Increases risk of bradycardia and pro-arrhythmic effect

ACE-I and NSAIDS
May cause renal dysfunction

Diuretic (Frusemide) and Gout
Decreases urate excretion —> diuretic-induced hyperuricaemia

49
Q

Known adverse drug reaction for ACE-I

A

Angioedema (bradykinin-induced angioedema)
- may present with mild episodes and progress to having severe life-threatening episodes
- self-limiting
- could occur in isolation/with urticaria/a component of anaphylaxis
- gravity-independent areas: face, lips, tongue, uvula, larynx, extremities and genitalia, bowel wall (jejunum) (— colicky pain, obstruction, ascites)

50
Q

Hereditary Angioedema (HAA)
VS
Acquired C1 Esterase Inhibitor (C1-INH) Deficiency

A

HAA - often in young patients

C1-INH Deficiency
- AKA Acquired Angioedema (AAE)
- Recurrent episodes of angioedema without urticaria
- often older than 40 years old