Pharmacology

Question 1

MOA, side effects of cimetidine, famotidine, ranitidine

Answer 1

MOA: H2 receptor antagonists —> decrease H+ secretion and Pepsi open secretion. Cimetidine also has immunomodulatory effects. Ranitidine also has prokinetic effects (acetylcholinesterase inhibitor)

Side effects: bradycardia, hypotension, arrhythmias (with rapid IV admin); cytopenia with cimetidine

Question 2

MOA, side effects of omeprazole, pantoprazole, esomeprazole

Answer 2

PPIs - inhibits H+/K+ ATPases on parietal cells

SE: diarrhea

Question 3

MOA, side effects of misoprostal

Answer 3

MOA: synthetic PGE1 analog

SE: GI upset, uterine contractions, vaginal bleeding

Exposure risk to female owners

Question 4

MOA, side effects of sucralfate

Answer 4

MOA: reacts with HCl in stomach forming a paste-like complex that binds the protein across exudates at ulcer sites —> creates a physiochemical barrier

SE: generally well-tolerated, rarely constipation

Considerations: best given on an empty stomach and separated from other drugs by two hours.

**Impairs absorption of antacids, ciprofloxacin, digoxin, ketoconazole, levothyroxine, macrolides, penicillamine, tetracyclines, theophylline, fat soluble vitamins, and warfarin

Question 5

MOA, side effects of true antacids (calcium carbonate, sodium bicarbonate, magnesium salts, aluminum salts, and phosphate binders)

Answer 5

MOA: inorganic, relatively insoluble starts that partially neutralize gastric HCl when dissolved in the stomach (however large doses are needed to raise pH significantly)

SE: generally well tolerated

Question 6

MOA, side effects of amyloid pine

Answer 6

MOA: calcium channel blocker —> results in peripheral arterial dilation with minimal cardiac effects

SE: reversible gingival hyperplasia, hypotension, bradycardia, inappetence

Question 7

When used for hypertension, what magnitude of blood pressure reduction would you expect when giving amlodipine with an ACEi vs. ARB?

Answer 7

ACEi: 30-70mmHg
ARB: 10-20mmHg

Question 8

MOA and side effects of enalapril and benazepril

Answer 8

MOA: angiotensin converting enzyme (ACE) inhibitor

SE: GI upset, hypotension, weakness, azotemia, and hyperkalemia

Question 9

Enalapril has __ excretion

Benazepril has __ excretion

Answer 9

Enalapril = renal

Benazepril = hepatic

Benazepril may be preferred in cats with renal disease

Question 10

MOA, side effects of telmisartan

Answer 10

MOA: angiotensin-II receptor blocker (ARB) - specifically blocks type 1 receptor (with 3000x more affinity than type 2)

Side effects: GI upset, hypotension, weakness, azotemia, hyperkalemia

Question 11

MOA and side effects of atenolol

Answer 11

MOA: Beta-1 blocker

SE: diarrhea, inappetence, lethargy, bradycardia, hypotension, impaired AV condition, congestive HF, bronchoconstriction (less so with Beta-1 specific drugs), syncope

Question 12

Amphotericin B is fungiSTATIC/CIDAL and concentration DEPENDENT/INDEPENDENT

Answer 12

Fungicidal

Concentration DEPENDENT

Question 13

Spectrum, side effects of amphotericin B

Answer 13

Spectrum: broad spectrum (most systemic fungal infections, disseminated sporotrichosis, candidiasis, aspergillosis)

Side effects: nephrotoxicity in >80% of patients; anaphylaxis, fever, vomiting, anorexia, thrombophlebitis, hepatic dysfunction

**Newer formulas are available that increase hydrophobicity —> increased delivery to target site with decreased delivery to kidney

Question 14

Polyenes antifungals and MOA

Answer 14

Amphotericin B
Nystatin, natamycin

MOA: interference with cell membrane function by binding ergosterol, forming pores in the fungal cell membrane which alters permeability

Question 15

Spectrum of nystatin and natamycin

Answer 15

Broad spectrum

Question 16

Route of administration of amphotericin B vs. nystatin

Answer 16

Amphotericin B = IV
Nystatin = topical

Question 17

Azole antifungals and MOA

Answer 17

Types: Ketoconazole, itraconazole, fluconazole, voriconazole, posiconazole

MOA: inhibition of cell membrane (ergosterol) synthesis

Question 18

Azoles are fugniCIDAL/STATIC

Answer 18

Fungistatic

Question 19

Spectrum and side effects of ketaconazole

Answer 19

Spectrum: topical mycotic infections (dermatology ties), Malassezia, dimorphism fungi (cryptococcosis)

Side effects: GI signs, hepatotoxicity (mild to moderate increases in ALT), ataxia, alopecia; can block cholesterol, cortisol, and androgen synthesis; lightening of hair coat

Question 20

Spectrum and side effects of itraconazole

Answer 20

Spectrum: broad (most fungal diseases)

SE: GI signs, hepatotoxicity, vasculitis/ulcerative skin lesions

**No blockage of adrenal steroid or testosterone synthesis compared to ketoconazole

Question 21

Which azole can reach the CSF?

Answer 21

Fluconazole

Question 22

Spectrum and side effects of fluconazole

Answer 22

Spectrum: most candida, dermatophytes, dimorphic fungi (cryptococcus, coccidiomycosis, histoplasmosis, blastomycosis)

Side effects: GI signs and mild elevation in liver enzymes

Question 23

Spectrum and side effects of voriconazole

Answer 23

Spectrum: wide

SE: teratogenic, GI upset, hepatotoxicity

Question 24

Spectrum and side effects of posaconazole

Answer 24

Spectrum: wide
SE: GI upset, hepatotoxicity

Question 25

What class of antifungal is terbinafine and what is the MOA

Answer 25

Class: Allylamine MOA: inhibits synthesis of ergosterol (main sterol in fungal cell membrane)

Question 26

Terbinafine is fungiSTATIC/CIDAL

Answer 26

Fungicidal

Question 27

Spectrum and side effects of terbinafine

Answer 27

Spectrum: Broad (aspergillosis, blastomycosis, cryptococcosis, histoplasmosis, coccidiomycosis, Malassezia) SE: mile liver enzyme elevations, GI upset, facial dermatitis and pruritis in cats

Question 28

What class of antifungal is caspofungin and what is its MOA

Answer 28

Class: Echinocandin MOA: blocks synthesis of the cell wall by interrupting glucagon synth ease complex

Question 29

Spectrum and side effects of caspofungin

Answer 29

Spectrum: disseminated Candida infections (fungicidal) and aspergillosis (fungistatic) SE: fever, phlebitis, rash (histamine-release) and increased ALT

Question 30

MOA of griseofulvin; cidal or static?

Answer 30

MOA: inhibits mitosis via disruption of the mitosis spindles causing mitosis arrest Fungistatic

Question 31

Spectrum and side effects of griseofulvin

Answer 31

Spectrum: limited to organisms causing dermatophytosis; NOT effective against yeasts SE: vomiting, teratogenesis and anemia (at high doses in cats)

Question 32

What is lufenuron and it’s MOA

Answer 32

Benzylphenol urea derived from insecticide used as an oral flea control; can be used as antifungal MOA: interferes with chitin synthesis (in outer cell wall of fungi)

Question 33

What is 5-flucytosine and MOA

Answer 33

Originally anti-cancer, can be used as antifungal but rapid resistance develops (especially for cryptococcosis and candidiasis) MOA: interferes with RNA and DNA synthesis after conversion to 5-FU (prevents synthesis in fungal cell) Fungistatic and time dependent Spectrum: Limited (cryptococcosis, candidiasis, aspergillosis, sporotrichosis) SE: BM suppression, GI upset

Question 34

What classes of antiarrhythmics are used for tx of supraventricular tachycardia

Answer 34

Beta blockers Calcium channel blockers Digoxin

Question 35

What classes of antiarrhythmics are used for tx of ventricular tachycardia

Answer 35

Acronym = SPAAM Sotalol Procainamide Atenolol Amiodarone Mexiletine

Question 36

What is used to treat bradyarrhythmias?

Answer 36

Pacemaker

Question 37

MOA of pimobendan

Answer 37

Calcium sensitizer (acts on heart muscle) → positive inotrope Phosphodiesterase-3 inhibitor arterial and venous vasodilation) – arterial vasodilation (decreasing after load) and venous vasodilation