TB, FLU, Fun

Question 1

Amphotericin B

Answer 1

Forms complex with ergosterol and disrupts the fungal plasma membrane. alters permiablility of fungal cell

wide spectrum of use

Prepped as a colloid or lipid formula for IV inject, poorl absorbed from GI

Question 2

Amphotericin B adverse effect

Answer 2

Immediate: Fever, chills, musle spasms, headaceh, hypotension

Long term: Renal damage, irreversible tubular renal damage, anemia (reduced EPO prod), seizures

Question 3

Flucytosine

Answer 3

Converted intracellularly to 5-FU and then to FdUMP and FUTP

FdUMP inhibs DNA synth
FUTP inhibs RNA synth

Used for cyrpto and some candida

used in combo with ampho B for crypto meningitis

PO, causes bone marrow toxicity and derange liver enzymes

Question 4

Ketoconazole

Answer 4

Imidazole
Reduction of ergosterol synth by inhib P450

greater affinity for fungal than human P450
Has less selectivty versus the triazoles

Question 5

Fluconazole

Answer 5

High oral bioavailabilty and IV
Good cerbral spinal fluid peentration
Least effect of all azoles on hepatic enzymes
Wide therapeutic index so can dose aggresively

Prophylaxis of cyrpto meningitis
no activity against aspergillus

Question 6

Itraconazole

Answer 6

Reduced bioavailabilty when taken with rifamycin
poor penetration of cerebral spinal fluid
Dimorphic fungi, dermatophytoses and onychimycosis

Question 7

Voriconazole

Answer 7

Oral and IV
Inhibits human CYP3A4 (dose reduction needed for statins)
Enhanced activity against aspergillus

Adverse: Elevated liver enzymes, visual disturbances, photosensitive dermatitsi

Question 8

Posaconazole

Answer 8

Inhibits human CYP3A4

Prophylaxis during chemo for leukemia and allogenic bone marrow tranplant

Question 9

Echinocandins

Answer 9

Caspofungin, Micafungin, anidulafungin

Inhibit synthesis of beta(1-3)-glucan at the fungal cell wall by inhibiting glucan synthase

Micafungin tx for candida in bone marrow trans px

Question 10

Oseltamivir, zanamivir, peramivir

Answer 10

Neuraminidase inhibitors
Stops virons from detaching from cell

Flu A and B use

Adverse: hallucinations, delirium and abnormal behavior

Zanamivir inhaled, peramivir-IV, Osteltamivir-PO

Question 11

Adamatanes

Answer 11

Amantadine and Rimantadine

Block M2 proton ion channel of the virus particle and inhibit uncoating of the viral RNA within infected cells, thus preventing replication

Only Flu A, PO

Question 12

TB 1st line RIPE

Answer 12

Rifampin, isoniazid, pyrazinamide, ethambutol

Isoniazid and rifampin are the most active
Ethambutol added to provide coverage in RI resistant TB strains

Question 13

Isoniazid

Answer 13

Inhibits mycolic acid synthesis (component of myco cell wall)

Prodrug that is activated by KatG

Adverse: Hepatitis, peripheral neuropathy (B6 deficiency)

Question 14

Rifampin

Answer 14

Inhibits RNA synthesis by binding to the beta subunit of bacterail DNA dependent RNA polymerase

Strong inducer of cytochrome P450, which increases the meta of many other drugs

Must be admin w/ other TB meds (iso) to stop resistance

Orange body fluid

Question 15

Ethambutol

Answer 15

Inhibits myco arabinosyl transferase (make arabinoglycan, needed for cell wall)

Retrobulbar neuritis, red-green color blind

Question 16

Pyrazinamide

Answer 16

Converts pyrazinoic acid, disrupts myco cell membrane medabolism and transport function

Hepatotoxicity, hyperuricemia