Pharmacology

Question 1

Name the two ways in which drugs are classified

Answer 1

1. The way in which they bring about their effect on the body
2. The body system or infective agent they affect

Question 2

Antimicrobial Agents

Answer 2

used to treat infections caused by

bacteria
fungi
virus
protozoa

Question 3

Antibacterial drugs

Answer 3

may be bacteriocidal or bacteriostatic

will be narrow or broad spectrum

Question 4

Bacteriocidal drugs

Answer 4

The drug kills the bacteria

Question 5

Bacteriostatic

Answer 5

The drug stops the bacteria multiplying

means the immune system host must be able to defeat the organism. Not suitable if immunocompromised i.e. cats with FLV

Question 6

Penicillin

Answer 6

e.g. amoxycilin

Broad spectrum

Bacteriocidal

Question 7

Tetracyclines

Answer 7

e.g. Oxytetracycline

Broad spectrum

Bacteriostatic

Question 8

Antiviral drugs

Answer 8

Not often used in small animal practice

feline herpes virus treated with aciclovir

(only viral treatment that’s not a vaccine)

Question 9

Ivermectin Characteristics

Answer 9

acts by enhancing the actions of certain compounds in the body which inhibits nervous transmission.

It can produce an adverse reaction in collies

Question 10

Praziquantel Characteristics

Answer 10

(In Milbemax)

effective against a wide range of tapeworms.

It increases the permeability of the cell membrane of the worm

resulting in a leaking of intracellular calcium & paralysis of the worm

Question 11

Cardiac Drugs

Answer 11

Have a complex mode of action

multiple drugs are often prescribed at the same time (consider drug interactions)

Some cardiac drugs have serious side effects

Question 12

Beta Blockers

Answer 12

anti-arrhythmic drugs

inhibit the stimulation of the beta receptors in the heart thereby reducing arrythmias e.g. propranolol

Question 13

Digoxin

Answer 13

Similar effect to sympathomimetics, drug of choice for long term use.

has a very small theraputic index so must be used with care (toxic if dose slightly wrong)

Question 14

Vasodilators

Answer 14

help to relax smooth muscle of the blood vessels which helps the blood to flow

reduces the amount of work the heart has to do to pump blood around the body

(arterial, veno and mixed dilators)

Question 15

Mixed Vasodilator

Answer 15

acts on the arteries and veins

e.g. enalapril

Question 16

Diuretics

Answer 16

increase the volume of urine produced and the amount of salt excreted

classified according to their mode of action

Question 17

Loop Diuretics

Answer 17

Refers to action - loop of henle

causes diuresis by inhibiting the reabsorption of sodium from the loop of henle

Because sodium is in the urine, water is also retained

at the level of the distal convoluted tubule , potassium is exchanged for sodium. So sodium is reabsorbed back into the body while potassium is excreted.

Because osmotic pressure of the urine stays the same, the water stays in the urine and is excreted from the body along with the potassium.

Therefore, loop diuretics can result in hypokalaemia (K deficiency)

e.g. frusemide

Question 18

Potassium Sparing Diuretics

Answer 18

Actively antagonises the production of aldosterone.

Aldosterone is the hormone responsible for the absorption of sodium from distal convoluted tubules and collecting ducts.

Because spironolactone stops aldosterone, sodium is not resorbed into the body, resulting in water not being reabsorbed either.

Potassium remains in the body because sodium is excreted, hence the name potassium sparing diuretics

Question 19

What happens if ACE inhibitors and potassium sparing diuretics are used concurrently?

Answer 19

Hyperkalaemia may develop