Pharmacology & Toxicology

Question 1

severe cutaneous adverse reaction allele

Answer 1

HLA-B *5801

Question 2

type 1 diabetes allelee

Answer 2

HLA-B18

Question 3

coeliac allele

Answer 3

HLA-DQ2

Question 4

Multiple sclerosis allele

Answer 4

HLA-DR15

Question 5

Trastuzumab

Answer 5

Trastuzumab (Herceptin) - monoclonal antibody that acts on the HER2/neu receptor

cardiotoxicity as SE - echo recommended prior to starting treatment

Question 6

Brimonidine MoA

Answer 6

Brimonidine is an alpha-2-adrenergic agonist aiding in the management of open-angle glaucoma by decreasing aqueous humour production and increasing uveoscleral outflow.

BRIMonidine stops the aqueous humou fom BRIMMING ove/reaching the BRIM

Question 7

Brinzolamide MoA

Answer 7

Brinzolamide is a carbonic anhydrase inhibitor that decreases aqueous humour production.

ZOLAMIDE = carbonic anhydrase inhibitor

Question 8

Pilocarpine MoA

Answer 8

a muscarinic agonist which works by contracting the ciliary muscle, in turn opening the trabecular meshwork and thus increasing outflow of aqueous humour.

Used for open angle glaaucoma

Question 9

Antibiotic class to be avoided in G6PD and what happens

Answer 9

Quinolones e.g. cipoflox

Heamolytic anaeamia with G6PD

Question 10

managment of lithium toxicity

Answer 10

Management
mild-moderate toxicity may respond to volume resuscitation with normal saline
IV fluids with isotonic saline, until euvolemic, then typically twice maintenance rate
monitor serum sodium closely (every 4 hours with serial lithium concentrations) if there is a concern about lithium-induced nephrogenic diabetes insipidus
haemodialysis may be needed in severe toxicity
sodium bicarbonate is sometimes used but there is limited evidence to support this
by increasing the alkalinity of the urine it promotes lithium excretion

Question 11

Carbon monoxide poisoning 1st line treatment

Answer 11

Carbon monoxide poisoning: 100% high-flow oxygen is the first-line treatment

Question 12

Drug-induced impaired glucose tolerance

Answer 12

TASTINg Sugar( impared glucose tolerance)

Thiazides, Antiphychotics, Steroids, T cell in inhibitors(tacrolimus |&| cyclosporin), interferon alpha, nicotinic acid.
Sugar = impared glucose tolerance

Question 13

buprenorphine MoA in opiod addiction

Answer 13

buprenorphine is a partial agonist of the mu-opioid receptor and an antagonist of the kappa-opioid. It binds to the mu-opioid receptors in the brain but only partially activates them. This partial activation is enough to alleviate cravings and withdrawal symptoms in individuals with opioid dependence. Furthermore, the binding of buprenorphine to the mu-opioid receptor is very strong, or ‘high affinity,’ meaning it can displace other opioids from these receptors and prevent them from exerting their effects. As a kappa-opioid receptor antagonist, buprenorphine may contribute to its ability to reduce symptoms of opioid withdrawal and potentially reduce depressive and dysphoric states.

Question 14

characteristic of methanol toxicity

Answer 14

metabolic acidosis with a high anion gap; presents with visual disturbances that are characteristic of methanol toxicity

Question 15

ethylene gycol toxicity management

Answer 15

fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol

Question 16

P450 inducers:

Answer 16

SCRAP GPS
Smoking
Carbamazepine
Rifampicin
Phenytoin
Griseofulvin
phenobarbitone
St John’s Wort

Question 17

Flecanide MoA

Answer 17

Flecainide blocks the Nav1.5 sodium channels in the heart
Slows the upstroke of the cardiac action potential by blocking Nav1.5 sodium channels is correct. Flecainide is a Class I antiarrhythmic drug and a potent inhibitor of the cardiac (Nav1.5) sodium channel. This results in slowing of the upstroke of the cardiac action potential thereby ‘reducing excitability’.

Question 18

COCP Cancer risk

Answer 18

Protective: Ovarian & endometrial
Increased risk: Breast & cervical

Question 19

Clinical examples of monoclonal antibodies:
infliximab (anti-TNF): used in rheumatoid arthritis and Crohn’s
rituximab (anti-CD20): used in non-Hodgkin’s lymphoma and rheumatoid arthritis
cetuximab (epidermal growth factor receptor antagonist): used in metastatic colorectal cancer and head and neck cancer
trastuzumab (HER2/neu receptor antagonist): used in metastatic breast cancer
alemtuzumab (anti-CD52): used in chronic lymphocytic leukaemia
abciximab (glycoprotein IIb/IIIa receptor antagonist): prevention of ischaemic events in patients undergoing percutaneous coronary interventions
OKT3 (anti-CD3): used to prevent organ rejectio

Question 20

Aspirin MoA

Answer 20

irreversible COX1 and COX2 inhibitor

Aspirin works by blocking the action of both cyclooxygenase-1 and 2. Cyclooxygenase is responsible for prostaglandin, prostacyclin and thromboxane synthesis. The blocking of thromboxane A2 formation in platelets reduces the ability of platelets to aggregate which has lead to the widespread use of low-dose aspirin in cardiovascular disease.

Question 21

Adverse effects of quinolones

Answer 21

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

Question 22

Drugs affected by acetylator status

Answer 22

isoniazid
procainamide
hydralazine
dapsone
sulfasalazine

HI-SPeeD
H - hydralazine
I - isoniazid
S- sulfasalazine
P - procainamide
D- dapsone

Question 23

Drugs exhibiting zero-order kinetics

Answer 23

phenytoin
salicylates (e.g. high-dose aspirin)
heparin
ethanol

t
he zero order drugs illustrate what comes after ‘love at first sight’, ie:
Alcohol
MI (high dose ASA, heparin)
Seizures, and thus need for phenytoin

Question 24

First-pass metabolism

Answer 24

aspirin
isosorbide dinitrate
glyceryl trinitrate
lignocaine
propranolol
verapamil
isoprenaline
testosterone
hydrocortisone

Question 25

Cyanide poisoning

Answer 25

Presentation
‘classical’ features: brick-red skin, smell of bitter almonds
acute: hypoxia, hypotension, headache, confusion
chronic: ataxia, peripheral neuropathy, dermatitis

Management
supportive measures: 100% oxygen
definitive: hydroxocobalamin (intravenously), also combination of amyl nitrite (inhaled), sodium nitrite (intravenously), and sodium thiosulfate (intravenously)