PDA anti-everything else Flashcards
What increases risk for TB?
socioeconic very low
TB-endemic area travel or immigration
immunocompromised
What are the challeges of antimycobacterial therapy?
difficult to kill
vunerable to -cidal drugs only when metabolically active
small population semi-dormant
slow growth-hampers identification/susceptibility
lengthy therapy
intracellular forms
chronic disease
spontaneous resistance requires multi-drug therapy
What are the side effects of isoniazid?
hepatotoxicity
neurotoxicity-peripheral neuritits
improved with pyridoxine and vitamin B6 admin
What drugs are first line TB drugs?
Isoniazid Rifampin Ethambutol Pyrazinamide Streptomycin
What is isoniazid mechanism of action?
inhibits synthesis of mycolic acid by targeting the enoyl acyl carrier protein reductase
activated by catalse peroxidase
cidal for actively growin bacilli
What is resistance to isoniazid?
very high up to 25% in some cities, spontaneous resistance
What is isoniazid use?
primary TB drug most important; given in combination
Tx active TB given in combination
can be given alone for latent TB
What are the side effects of RIfampin?
Hepatotoxicity and inducer of multiple CYPs
orange-red color of body secretions
What is the mechanism of action of Ethambutol?
interferes with arabinosyl transferase blocking cell wall syntehsis
Tuberculostatic and enhances the permeability for drugs
What are the side effects of ethambutol?
well-distributed generally well tolerated but causes optic neuritis
decreased visual acuity or loss of ability to differentiate red-green
What is mechanism of action of pyrazinamide?
blocks mycolic acid syntehsis by inhibiting fatty acid synthase I, -cidal
Pyrazinamide is particulary useful for TB with what involvement?
CNS involvement because of distribution
What are the adverse effects of Pyrazinamide?
hepatic damage, adds to hepatotoxicity of other drugs
What is the mechanism of streptomycin?
aminoglycoside, binds to several ribisomal sites and cause mRNA misreading
usually reserved for most serious forms of TB
What are the side effects of streptomycin?
renal damage
and ototoxciity efecting both balance and hearing
What does tx of short-course uncomplicated TB requrie?
isoniazid plus rifampin plus pyrazinamide for the first two months
How does one treat disseminated TB?
isoniazid plus rifampin for 9 mos-2yrs and others for first two months
Why use simultaneous 4 or more drugs?
disseminated disease, meningitis, known exposures to drug-resistant strains, severe pulmonary disease
How does one treat XDR TB?
5 or more drug treatments at once
What are atypical mycobacterial infections?
MAC= m. avium intracellulare complex
among most frequent opportunistic infections in AIDS
less fatal than TB
What does rifabutin do/ mechanism of action?
prophylaxis of MAC
similar to Rifampin but less severe side effects
What is clarithromycin used to treat with regards to mycobacteria?
tx of MAC in AIds patients and MAC prophylaxis
What is dapsone sued to treat?
leprosy and pneumocystis jiroveci in AIDs pats
What is the mechanism of action of Dapsone?
structural analog of para-aminobenzoic acid; inhibits syntehsis of folic acid
What are the side effects of Dapsone?
hemolytic anemia
methemoglobinemia
dose depndent
What is teh mechanism of Clofazimine?
mechanism poorly understood; somehow binds to DNA and interferest with growth
What is Clofazimine used to treat?
Leprosy
What are the adverse side effects of Clofazimine?
well tolerated
GI problems and red-brown pigmentation of eyes and skin
What drugs are used to treat leprosy?
Clofazimine, Dapsone and Rifampin
What is amphotericin B used to treat?
effecctive broad spectrum anti-fingal for most systemic myoces; esp those that are life-threatening
Gold-standard for anti-fungal effectiveness
What is the mechanism of action of amphotericin B?
Binds to ergosterol; very lipophilic
Why is hte total cumulative dose of Amphotericin important?
permanent renal toxicitiy is related to the total cumulative dose
What is the side effects of amphotericin?
fever, nausea, vomiting, headache, chills
hypotension, hypokalemia, tachypnea
90% will show non-permanent renal toxicity
reversble hypochromic, normocytic anemia
cnS side effects
What flucytosine (5-FC) used to treat?
serious infections of candida and crytpococcus
used in conjunction wiht amphotericin
What si the mechanism of action of flucytosine?
inhibits thymidylate synthetase and thus DNA syntehsis
incorporated in RNA in place of Uracil
fungal cytosine deaminase activates it
What are the side effects of flucytosine?
GI
leukopenia, thrombocytopenia
may accumulate in renal insufficiency and dangerous in bone marrow suppresion
elevated hepatic enzymes
What are the two antifungal classes for serious infections?
imidazole and triazole
What are the mechanism of actions of imidazole and triazoles?
inhibits 14-alpha-sterol demethylase a fungal cytochrom p450 that conferst lanosterol to ergosterol
inhibits ergosterol syntehsis
SLOW onset of action
What is fluconazole used to treat?
cryptococcus meningits
Candida many sites including CNS and urinary; some albican and glabrata but not krusei
excreted in urine so good for urinary
What is itraconazole ussed to treat?
Blastomyces, histoplasma, candida esophogause and oropharynx
more albican and glabatra some krusei
What is voriconazole used to treat?
aspergillus with some CNS coverage
Fusarium, Scedosporium, Candida–>covers most species but not for urinary candida infections
What drug is superior to amphotericin for invasive aspergillus?
voriconazole
What azole has best CNS penetration?
fluconazole
What are the side effects common to -azoles?
mild hepatotoxicity; discontinue with onset of liver dysfunciton
GI, headache
CYP3A and 2C inhibitors
What is the major contraindication of itraconazole?
other drugs that are metabolized by CYP3A4; and potential for serious CV events
What azole has lowest incidence of hepatotoxicity?
fluconazole
What unusal side effects do voriconazole have?
visual disturbance and photosensitive component to rash
What anti-fungals target the cell wall?
caspofungin*
micafungin
anidulafungin
What is Caspofungin used to treat?
aspergillus-invasive
Candida with wide coverage
What is mechanism of action fo capsofungin?
inhibits fungal cell wall ysntehsis by noncompetively blocking syntehsis of Beta-D-glucan in filamentous fungi
No cross resistance mechanisms
What are the side effects fo capsofungin?
phlebitis at injection site
GI effects
some pulm edema but generally well tolerated
Fluconazole is used to treat what other than serious infections?
superficial fungi; often one oral dose all thats required
miconazole is used to treat what?
creams/suppositories to treat vaginal infections
What is clotrimazole used to treat?
candida; topical use
Nystatin is what mechanism of action?
similar to amphotericin B
What is nystatin used to treat?
superficial fungi; for -azole resistant strains
topical use for candida and GI tract
What are the side effects fo Nystatin?
Some GI side effects but topical well toleratied
What is natamycin used for?
opthalmic infections by fungal infectionss
What is mechanism of action of natamycin?
similar to amphotericin B; too toxic for systemic
What are used for topical treatment of dermatophytes?
miconazole, clotrimazole
tolnaftate-
terbinafine
ciclopirox
What is mechanism of action of tolnaftate?
likely inhibits fungal ergosterol syntehsis
few toxic reactions topical only
What is ciclopriox used for?
approved topical tx for mild to moderate fungal nail infections
What is the ciclopirox mechanism of action?
inhibits metal-depndent fungal enzymes by metal chelation is the believed mechanism
What are the oral preapartions of dermatophyte used for?
severe dermatophyte infections
those that are resistant
What is terbinafine used for?
12-week thereapy for nail infections
shorter for other dermatophytic infections
What is the mechanism of action of terbinafine?
deposits in skin and nails leadign to prolonged effect
blocks ergosterol syntehsis and causes accumulation of squame which is toxic to fungi