Prototype Drug Unit 3 & 4- Ranitidine (Zantac)

Question 1

Therapeutic classificaiton

Answer 1

Antiulcer drug

Question 2

Pharmacologic classificaiton

Answer 2

H2-receptor antagonist

Question 3

Therapeutic effects and uses

Answer 3

taken once daily, usually at bedtime

Ulcer healing in 4-8 weeks, but can be used for prolonged periods to prevent re-occurrence

Question 4

Mechanism of action

Answer 4

Blocks H2 receptors on the parietal cells in the stomach to decrease acid production

Question 5

Route

Answer 5

PO, IV, IM

Question 6

Absorption

Answer 6

Rapid absorption following PO administration; all three routes acheive comparable blood levels

Question 7

Distribution

Answer 7

PO bioavailability is approximately 50%; very little enters the CNS; crosses the placenta; secreted in breast milk; 15% bound to plasma protein

Question 8

Primary metabolism

Answer 8

Hepatic

Question 9

Primary excretion

Answer 9

Renal

Question 10

Adverse effects

Answer 10

Headache, nausea, dry mouth

Question 11

Contraindications/precautions

Answer 11

Contraindications: hypersensitivity, acute porphyria, and OTC administration in children younger than 12

Precautions: renal impairments

Question 12

Drug interactions

Answer 12

Reduce absorption of cefpodoxime, ketoconazole, and itraconazole.
Concurrent use can increase the effects of alcohol, sulfonylureas, salicylates, and warfarin.
Antacids should not be given within 1 hour of H2 receptor antagonists because they reduce absorption.
Smoking decreases effectiveness

Question 13

Herbal/food interactions

Answer 13

deficiency of B12 may occur and Iron may increase

Question 14

Pregnancy category

Answer 14

B