Urinary Tract Antiseptics And Tuberculosis

Front 1

Describe the properties of urinary tract antiseptics which make them effective only within the urinary tract.

Back 1

Urinary tract antiseptics have no intended systemic activity and exert their effects entirely within the urinary tract because they:

1) are rapidly eliminated
2) exhibit high protein binding
3) are found in high urinary concentrations
4) are found in low serum concentrations
5) require low pH to be effective

Front 2

Name the 3 urinary tract antiseptics discussed in class.

Back 2

1) nitrofurantoin
2) methenamine
3) fosfomycin

Front 3

This urinary tract antiseptic may cause GI upset and headache. More significantly, though, it may cause an acute allergic reaction that affects the lungs; a chronic form may cause pulmonary fibrosis.

a) fosfomycin
b) daptomycin
c) nitrofurantoin
d) methenamine

Back 3

This urinary tract antiseptic may cause GI upset and headache. More significantly, though, it may cause an acute allergic reaction that affects the lungs; a chronic form may cause pulmonary fibrosis.

c) nitrofurantoin

Front 4

What are the clinical uses of nitrofurantoin?

What is the clinical use of methenamine?

Back 4

Nitrofurantoin is prescribed for..
1) acute cystitis
2) UTI prophylaxis

Methenamine is used as cystitis prophylaxis.

Front 5

Daptomycin acts:

a) only on Gm(+)
b) only on Gm(-)
c) on both Gm(+) and Gm(-)

Back 5

Daptomycin acts:

a) only on Gm(+)

Front 6

Describe the mechanism of action of daptomycin.

Back 6

Daptomycin has a lipophilic tail that it uses to bind to and disrupt the the cell membrane of Gm(+) organisms. The binding and disruption is a calcium-dependent process.

Daptomycin molecules aggregate and form pores in the cell membrane, allowing potassium ions to leak out.

Front 7

What are the clinical uses of daptomycin?

Back 7

Daptomycin treats..
1) soft tissue infections
2) MRSA, VRSA, VRE
3) spectrum that closely overlaps that of vancomycin

**Daptomycin only acts against Gm(+) bacteria**

Front 8

This drug acts at the bacterial cytoplasmic membrane.

a) nitrofurantoin
b) metronidazole
c) rifampin
d) daptomycin

Back 8

This drug acts at the bacterial cytoplasmic membrane.

Answer: d) daptomycin

Other answer choices:
a) nitrofurantoin: bacteria reduces a nitro group and free radical forms
b) metronidazole: similar to nitrofurantoin
c) rifampin: inhibits transcription by inactivating DNA-dep RNA polymerase

Front 9

What are the clinical uses of metronidazole?

For patients treated with metronidazole, what adverse effects might they experience?

Back 9

Metronidazole treats:
1) protozoal infections
2) anaerobic bacteria like C.diff, B.fragilis
3) H.pylori

Patients taking metronidazole might experience headaches, a metallic taste, and - if they drink alcohol - disulfuram-like reactions.

Front 10

Spectinomycin is used as an alternative to treat:

a) N.gonorrhea
b) T.pallidum
c) both N.gonorrhea and T.pallidum

Back 10

Spectinomycin is used as an alternative to treat:

a) N.gonorrhea

Spectinomycin is NOT active against T.pallidum. This is important clinically as gonorrhea and syphilis infections often present simultaneously. Thus, another drug must be used to treat T.pallidum.

Front 11

Identify the drug described by the following..

1) Treats protozoal infections and may cause a metallic taste and disulfuram-like reaction in those who drink alcohol.

2) Rapidly excreted by the kidney and has no systemic activity but may cause chills, cough, and pulmonary infiltrations.

3) Injectable drug used to treat M.tuberculosis that may cause ototoxicity.

4) Primary agent in the treatment of M.tuberculosis and may cause a peripheral neuropathy similar to that of a vitamin B6 deficiency.

5) Occasionally injected to treat resistant Pseudomonas infections but has not been widely used since 1980 due to its nephrotoxic effects.

6) Used to treat M.tuberculosis but may cause loss of red/green color discrimination.

7) Used to treat N.gonorrhea but is not active against syphillis.

Back 11

1) Treats protozoal infections and may cause a metallic taste and disulfuram-like reaction in those who drink alcohol = METRONIDAZOLE

2) Rapidly excreted by the kidney and has no systemic activity but may cause chills, cough, and pulmonary infiltrations = NITROFURANTOIN

3) Injectable drug used to treat M.tuberculosis that may cause ototoxicity = STREPTOMYCIN

4) Primary agent in the treatment of M.tuberculosis and may cause a peripheral neuropathy similar to that of a vitamin B6 deficiency = ISONIAZID

5) Occasionally injected to treat resistant Pseudomonas infections but has not been widely used since 1980 due to its nephrotoxic effects = POLYMIXIN B OR POLYMIXIN E (aka: colistin)

6) Used to treat M.tuberculosis but may cause loss of red/green color discrimination = ETHAMBUTOL

7) Used to treat N.gonorrhea but is not active against syphillis = SPECTINOMYCIN

Front 12

Why did polymixins fall into disuse in the late 70's/early 80's?

Today, under what circumstances are polymyxins administered?

Back 12

Polymixins fell into disuse because of their nephrotoxicity.

Injectable polymixins are occasionally needed in the case of Pseudomonas and other Gm(-) bacilli resistant to all other antimicrobial agents.

Front 13

Identify the drug that would be used to treat the following...

1) acute cystitis

2) protozoan infection or C.difficile infection

3) M.tuberculosis prophylaxis

4) Patient has a penicillinase-producing N.gonorrhea infection and is allergic to cephalosporins

Back 13

1) acute cystitis = NITROFURANTOIN

2) protozoan infection or C.difficile infection = METRONIDAZOLE

3) M.tuberculosis prophylaxis = ISONIAZID

4) Patient has a penicillinase-producing N.gonorrhea infection and is allergic to cephalosporins = SPECTINOMYCIN

Front 14

Why are multiple drugs always used to treat active cases of tuberculosis?

Back 14

Using multiple drugs to treat active tuberculosis decreases the chances of resistant organisms developing.

Since resistance occurs primarily due to mutations, each drug should have a separate mechanism of action. Thus, for a resistant organism to survive, it would have to develop resistance for all drugs simultaneously.

Front 15

Which drug is used for the prophylaxis of M.Tb?

Back 15

ISONIAZID is the only drug used for the prophylaxis of M.Tb.

Front 16

What is the mechanism of action of isoniazid?

How do M.tuberculosis organisms become resistant to isoniazid?

Back 16

Isoniazid requires a catalase/peroxidase enzyme to activate it. Once activated, isoniazid inhibits the synthesis of mycolic acids.

Bacteria become resistant to isoniazid due to mutations in the catalase/peroxidase enzyme.

Front 17

The rate-limiting step for Isoniazid elimination is via metabolism - primarily by acetylation. Why is this important clinically?

Back 17

A patient's acetylator status becomes important if he is taking isoniazid.

Slow acetylators will have a higher concentration of isoniazid in their plasma and will be more prone to develop peripheral neuritis.

Front 18

Your patient is taking isoniazid for M.tuberculosis prophylaxis. He develops a peripheral neuritis.

Why do you think this happened to your patient?

What can you do to treat him?

Back 18

Your patient might be a slow acetylator. Since the acetylation is the rate limiting step in isoniazid elimination, a slow acetylator will have a higher concentration of isoniazid in his plasma and will be more prone to develop peripheral neuritis.

Higher isoniazid levels leads to increased excretion of pyridoxine, and, as a result, a peripheral neuropathy similar to a pyridoxine deficiency.

Supplementing your patient's diet with vitamin B6 can counteract the isoniazid-induced pyridoxine excretion.

Front 19

What is the mechanism of action of rifampin?

Back 19

Rifampin inhibits transcription by inactivating bacterial DNA-dependent RNA polymerase. Rifampin is highly specific for this bacterial enzyme, with concentrations 10,000x higher being required to inhibit the corresponding mammalian enzyme.

Front 20

This M.tuberculosis drug is a a potent inducer of CYP34A and is involved in many drug interactions.

a) rifampin
b) ethambutol
c) isoniazid

Back 20

This M.tuberculosis drug is a a potent inducer of CYP34A and is involved in many drug interactions.

a) rifampin

Front 21

What are the adverse effects associated with isoniazid?

Back 21

Isoniazid adverse effects include..

1) peripheral neuropathy similar to pyridoxine deficiency

2) hepatotoxicity due to metabolism of acetylisoniazid to a toxic metabolite by the liver

Front 22

Identify the M.tuberculosis drug associated with the following adverse effects..

1) hyperuricemia and ocular toxicity

2) ototoxicity and nephrotoxicity

3) peripheral neuropathy and hepatotoxicity

4) hyperuricemia and hepatotoxicity

5) gradual loss of visual acuity and loss of red/green color discrimination

6) minor cutaneous and GI reactions but involved in many drug interactions related to CYP3A4

Back 22

1) hyperuricemia and ocular toxicity = ETHAMBUTOL

2) ototoxicity and nephrotoxicity = STREPTOMYCIN

3) peripheral neuropathy and hepatotoxicity = ISONIAZID

4) hyperuricemia and hepatotoxicity = PYRAZINAMIDE

5) gradual loss of visual acuity and loss of red/green color discrimination = ETHAMBUTOL

6) minor cutaneous and GI reactions but involved in many drug interactions related to CYP3A4 = RIFAMPIN

Front 23

Drugs used to treat tuberculosis infections can be taken orally, but this anti-tubercular drug has to be injected.

a) rifampin
b) streptomycin
c) ethambutol
d) isoniazid
e) pyrazinamide

Back 23

Drugs used to treat tuberculosis infections can be taken orally, but this anti-tubercular drug has to be injected.

b) streptomycin

Front 24

TRUE or FALSE

Daptomycin is active against growing bacteria, resting bacteria and biofilms.

Back 24

TRUE

Front 25

What 3 drugs discussed in class are used to treat leprosy?

Back 25

1) dapsone
2) clofazimine
3) rifampin

Front 26

What's the difference between the following drugs?

1) Streptozocin
2) Spectinomycin
3) Streptomycin

Back 26

1) Streptozocin: nitrosurea alkylating agent used in anti-cancer therapy

2) Spectinomycin - miscellaneous anti-bacterial that treats N.gonorrhea

3) Streptomycin - an aminoglycoside (protein synthesis inhibitor) that is used in the treatment of M.tuberculosis

Front 27

Differentiate these 2 drugs.

1) Dactinomycin
2) Daptomycin

Back 27

1) Dactinomycin - antibiotic used in anticancer therapy; it intercalates between base pairs of DNA

2) Daptomycin - antibacterial that acts at the bacterial cytoplasmic membrane; it treats only Gm(+) bac like MRSA, VRSA