Pharmacology

Question 1

What is the mechanism of action of Cyclizine?

Answer 1

H1-receptor antagonist [antihistamine]

Question 2

What is the indication for cyclizine?

Answer 2

motion sickness
Vertigo
Vestibular disorders

Question 3

What drugs is used for severe morning sickness of pregnancy?

Answer 3

Promethazine

Question 4

Describe the [harmacodynamics of Cyclizine?

Answer 4

peak anti-emetic effect 4 hours after ingestion

Question 5

What are the adverse effects associated with Cyclizine?

Answer 5

Drowsiness
Dry mouth
Blurred vision

Question 6

What anti-emetic drugs are h1 receptor antagonist?

Answer 6

Cyclizine
Cinnarizine
Promethazine

Question 7

What is the mechanism of action of Hyoscine?

Answer 7

Muscarinic receptor antagonist

Question 8

What is the indication of Hyoscine?

Answer 8

General purpose anti-emetics + prophylaxis

Question 9

What are the adverse effects of Hyoscine?

Answer 9

Dry mouth
Blurred vision
Sedative [less than antihistamines]

Question 10

Hyoscine

Answer 10

Scopolamine

Question 11

What is the mechanism of action of Ondansetron?

Answer 11

blocks 5-HT3 receptor in the chemoreceptor trigger zone

Question 12

What are the indication for Ondansetron?

Answer 12

Post-operative N&V

N&V due to cytotoxic drugs

Question 13

What are the adverse effects of Ondansetron?

Answer 13

Headache and GI upsets [uncommon]

Question 14

What is the mechanism of action of metoclopramide?

Answer 14

Block D2 receptors in CTZ [+ some actions on GIT]

Question 15

What is the pharmacokinetics of metoclopramide?

Answer 15

does not readily penetrates BBB ➡ less prone to produce central side effects

Question 16

What is the underlying cause of side effects of metoclopramide?

Answer 16

mainly due to the blocking of D receptors in CNS

Question 17

What is the mechanism of action of Lactulose?

Answer 17

Osmotic laxatives

retains fluids in bowels by osmosis [accelerates the transfer of gut contents through small intestines and results in large volume entering the colon ➡ dissension ➡ purgation]

Question 18

What is the mechanism of action of docusate sodium?

Answer 18

acts as an emulsifying or wetting agent to produce softer feces

Question 19

What are the indication for docusate sodium?

Answer 19

management of hemorrhoids and anal fissures

Question 20

Describe the pharmacodynamics of docusate sodium

Answer 20

Oral preparation acts within 1-2 days

Question 21

What is the mechanism of action of Codeine?

Answer 21

An opiate that decreases motility

Question 22

How do anti motility agents produce a constipating effect?

Answer 22

Causes a decrease in propulsive movement of the tract, increasing the transit time of intestinal contents, more water to be absorbed, making colonic contents firmer

Question 23

What are the unwanted effects of anti-motility agents?

Answer 23

Occurs with chronic use:
constipation
Drowsiness

Question 24

What is loperamide?

Answer 24

An opiate used an antimotilty agent

Question 25

Which opiate is preferred as an antimotility agent? Why?

Answer 25

Loperamide as poorly penetrates the CNS, producing less central effects

Question 26

What is the mechanism of action of loperamide?

Answer 26

acts on μ-opioid receptors in the GIT

Question 27

What is the mechanism of action of Senna?

Answer 27

Stimulate colonic activity & increase peristalsis (by stimulating enteric nerves), resulting in defecation.

Question 28

Pharmacokinetics of Senna

Answer 28

single dose produces laxative effect within 8 hours

Question 29

Pharmacokinetics of Bisacodyl

Answer 29

Administered oral or suppository [usually] causes stimulation of the rectal mucosa, results in peristaltic action and defecation in 15-30 minutes.

Question 30

Describe the how laxative dependency occurs

Answer 30

Overuse can lead to atonic colon and the only way to achieve defecation is to take further amounts of the laxatives

Question 31

Which drug are linked to hepatotoxicity in children under 3?

Answer 31

Valproic acid | Salicylates

Question 32

What drugs cause microvascular steatosis?

Answer 32

Valproic acid | High doses of tetracycline

Question 33

What characterizes microvascular steatosis?

Answer 33

modest elevations of aminotransferase levels in blood | Presence of lactic acidosis

Question 34

What drug induces cytochrome P450 isoenzyme 2E1?

Answer 34

Rifampicin

Question 35

Which drugs should not be co-administered with rifampicin? Why?

Answer 35

acetaminophen, isoniazid and halothane Increases risk of hepatotoxicity

Question 36

Which drugs are most frequently implicated in hepatic injury?

Answer 36

Acetaminophen Isoniazid Phenytoin Valporate

Question 37

What is the treatment of choice for acetaminophen overdose?

Answer 37

N-acetylcysteine

Question 38

What drugs cause macrovascular steatosis?

Answer 38

Steroid | Methotrexate

Question 39

What drugs cause intrinsic hepatotoxicity?

Answer 39

Acetaminophen | Methotrexate

Question 40

What is intrinsic hepatotoxicty?

Answer 40

Predictable, dose-dependent hepatotoxicity, occurring in all individuals who have taken a toxic dose. It has a distinctive pattern observed for any given drug and happens after a brief latent period of exposure to drug

Question 41

What is idiosyncratic hepatotoxicity?

Answer 41

Less predictable, dose-independent, causes hepatic damage only in small number of uniquely susceptible individuals, has a variable histological pattern of lesions and shows delayed onset (weeks to months)

Question 42

What are the associated symptoms of idiosyncratic hepatotoxicity?

Answer 42

Fever Rash Eosinophilia [allergy]

Question 43

What drugs cause idiosyncratic hepatotoxicity?

Answer 43

Halothane Isoniazid Chlorpromazine

Question 44

What are the possible causes of idiosyncratic hepatotoxicity?

Answer 44

drug hypersensitivity metabolic abnormality

Question 45

What drugs are implicated in hepatocellular necrosis?

Answer 45

Isoniazide | Acetaminophen

Question 46

What characterizes hepatocellular necrosis?

Answer 46

marked elevation of aminotransferase, followed by incense in serum bilirubin levels and modest increase in alkaline phosphatase

Question 47

Which drug are linked to hepatotoxicity in patients over 60 years?

Answer 47

Halothane | Isoniazid

Question 48

What drugs most commonly cause drug induced hepatoxicity in females?

Answer 48

Halothane | Isoniazid

Question 49

What drug may cause liver toxicity in patients that are slow and fast acetylators?

Answer 49

Isoniazid

Question 50

What drug causes canalicular type cholestasis?

Answer 50

contraceptive steroids

Question 51

What drug causes hepatpcanalicular type cholestasis?

Answer 51

Chlorpromazine

Question 52

What drug cause steatohepatitis?

Answer 52

amiodarone

Question 53

What drug causes hepatotoxicity by covalently binding to proteins, thus inducing an immunological reaction?

Answer 53

Halothane