4.1 Antibacterials, Antifungals, And Antiviral Agents

Question 1

Antifungals

Answer 1

Incidents continues to increase, particularly in patients who are required to take immunosuppressive drugs

Question 2

3 highly effective Antifungal drugs

Answer 2

Amphotericin B

Imidazoles (azoles)

Question 3

Amphotericin B

Answer 3

• binds to ergosterol combination causes pores to form, resulting in leakage across the fungal membrane.
• A is poorly absorbed from the gastrointestinal tract and must be administered intravenously for systemic fungal disease
• causes a variety of adverse effects, with kidney toxicity being the major dose-limiting toxicity

Question 4

Imidazoles

Answer 4

• effective when taken orally for systemic fungal infections
• inhibit fungal cytochrome p450 inhibiting ergosterol synthesis
• selective toxicity of the easels lies in their higher affinity for the fungal P450 then the human P450S that are involved in drug metabolism
• Number available as over the counter drugs for the treatment of yeast infections

Question 5

What step in pharmacokinetics are P450s involved in

Answer 5

Responsible for the metabolism of the vast majority of clinically used drugs

Question 6

Antivirals

Answer 6

-small infectious agent that is only able to multiply within the living cells of other organisms like plants animals and bacteria
Great need for additional and more effective antiviral drugs

Question 7

Two drugs for influenza

Answer 7

Amantidine

Oseltamivir

Question 8

Oseltamivir

Answer 8

Neuraminidase Inhibitor which is an enzyme that allows the spread of the virus from cell to cell drugs of this class prevent neighbouring cells from being infected with the virus

Question 9

Amantidine

Answer 9

Do you like inhibits the uncoating of viral RNA with an infected cells there by preventing viral infection used due to the influenza a virus

Question 10

Drug for HSV/VZV

Answer 10

Acyclovir
Taken up into infected cells virus activates drug to the active form
Inhibit viral DNA replication
Long term use well markedly decreased the frequency of reoccurrence of genital herpes

Question 11

Antibiotics

Answer 11

Purpose is to start bacterial infection by inhibiting the growth and reproduction of bacteria or by directly killing the bacteria

Question 12

Two ways antibiotics are classified

Answer 12

Narrow spectrum and broad-spectrum

Question 13

Narrow spectrum

Answer 13

Are only useful against particular species of micro organisms for example penicillin is only effective against gram-positive bacteria

Question 14

Broad-spectrum

Answer 14

Are effective against a wide range of micro organisms including both gram-positive and gram-negative for example tetracyclines

Question 15

Types of antibiotics and antibiotic targets

Answer 15

cell wall and cell membrane synthesis
Protein synthesis
Nucleic acid metabolism

Question 16

Cell wall and membrane synthesis

Answer 16

Two classes of antibiotics penicillin and cephalosporins

Question 17

Penicillin

Answer 17

Penicillin mould could produce and excrete and antibacterial substance wasn’t successfully isolated from the mould until the Second World War

Question 18

Penicillin mechanism of action

Answer 18

Closely related to a chemical necessary for the formation of new bacterial cell walls
It interferes with new bacterial cell wall formation and the resulting cells are formed without cell walls
These are known as protoplast and fragile and can readily burst human cells do not have cell walls and are therefore unaffected by penicillin so penicillin to selectively toxic to bacteria

Question 19

Adverse effects of penicillin

Answer 19

Allergic reaction with an individual is allergic to one penicillin preparation they will be allergic to all penicillin vibrations common manifestations include rash diarrhoea fever face and tongue swelling

Question 20

Two types of penicillin

Answer 20

Natural - penicillin G

semisynthetic - Penicilin v, methicillin, amphicillin, augmentin

Question 21

Penicillin G

Answer 21

Extracted and purified from penicillin mould mainly destroys gram-positive bacteria and is useful pneumonia middle year infection skin infections and meningitis also used for the treatment of syphilis

Question 22

Cephalosporins

Answer 22

Chemically similar to penicillin but in general are more resistant to penicillinase than is the penicillin group
Selective inhibitor’s of bacterial cell wall synthesis

Question 23

Adverse effects of cephalosporins

Answer 23

Fever and skin rashes renal toxicity may occur in rare cases if allergic to penicillin also allergic to this

Question 24

Inhibitors of bacterial DNA synthesis

Answer 24

Floroquinolones

Chemically distinct class of anti-micro biles and inhibit bacterial DNA synthesis example of ciprofloxacin can be used for oral or intravenous therapy

Question 25

Inhibitors of protein synthesis

Answer 25

Three classes of antibiotics tetracyclines, macrolides, and antifolate drugs

Question 26

Tetracyclines

Answer 26

First broad-spectrum antibiotics developed widespread use for many years many bacteria were formally susceptible to the action have become resistant

Question 27

Mechanism of action

Answer 27

Tetracycline spine to the 30 S subunit of the mRNA ribosome complex and prevent the addition of amino acids to the protein chain in Hibbett in protein synthesis

Question 28

Adverse effects

Answer 28

Gastrointestinal effects such as nausea vomiting and diarrhoea
Discolouration of teeth and diminished bone growth tetracyclines have a strong avidity For calcium
If kept for long periods of time they deteriorate into toxic degradation products

Question 29

Macrolides

Answer 29

Antibiotics are active against several bacterial infections caused by gram-positive microorganisms when organism is allergic to penicillin this is given

Question 30

Mechanism of action

Answer 30

Buying to the 50 S ribosomal subunits on tRNA and block peptide formation

Question 31

Adverse effects

Answer 31

Anorexia nausea vomiting and diarrhoea

Question 32

Antifolate drugs

Answer 32

Inhibitors to fully metabolism and microorganisms

Question 33

Two antifoliate drugs

Answer 33

Sulfonamides

Trimethoprim

Question 34

Sulfonamides

Answer 34

Sulphamethoxazole competitively inhibits an upstream step in the synthesis of Tetrahydrofolic acid by inhibiting PABA

Question 35

Trimethoprim

Answer 35

Inhibits dihydrofolic acid reductase does inhibiting tetrahydrofolic acid formation

Question 36

Antibiotic resistance

Answer 36

Emergence of resistant strains is a long-standing problem with antibiotics as micro organisms mutate to have different properties and therefore become resistant to antibiotics

Question 37

Two major factors associated with the development of antibiotic resistance

Answer 37

Evolution and clinical environmental factors

Question 38

Causes of antibiotic resistance

Answer 38

Physicians over prescribe antibiotics for a number of reasons such as lack of diagnostic equipment or pressure from drug companies and patients
Inappropriate use by patient may result from the patient not finishing their treatment
The use of antibiotics and agriculture may expose the animals to an unnecessary antibiotic which increases the risk of drug resistant development