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Pharm test 3
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86
Medical
Graduate
05/04/2009

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Term
Tetracyclines spectrum
Definition
Gram positive and negative plus Rickettsia, Mycoplasma and Chlamydiae. Not used too much though. Other drugs are better.
Term
Mechanism of Tetracyclines
Definition
Binds 30S ribosome. Blocks amino-acyl-tRNA binding.
Term
Absorption of tetracyclines
Definition
Incomplete except for doxycycline and minocycline. Dairy and divalent cations chelate and prevent absorption (except doxy and mino).
Term
Distribution of tetracyclines
Definition
Widely distributed, BBB, placenta etc.. Minocylcine is very lipophilic and can have sufficient concentration in saliva/tears to treat meningococcal carrier states.
Term
Tetracycline side effects
Definition
Gastrointestinal(most frequent)
Superinfections(Candida, staph, C. diff, esp in diabetics, leukemia or SLE)
Phototoxicity(esp w doxy and demeclocycline)
Bone defects (esp children, contraindicated in pregnancy)
Hepatotoxicity(pregno, liver diseased)
Renal Toxicity(Fanconi syndrome=prox tubule)
Vestibular toxicity(minocycline)
Term
Chloramphenicol Spectrum
Definition
Bacteroides fragilis and amp resistant H. influ/CNS anaerobes and life threatening meningitis.
Gram + and -, Rickettsia, mycoplasma and Chlamydiae.
Term
Chloramphenicol mechanism
Definition
Inhibits protein synthesis by binding 50S. Bacterial static except for highly susceptible strains of H. flu, N.men, and Strep. p.
Term
Chloramphenicol Therapeutic uses
Definition
1. Life threatening meningitis
2. Severe CNS Bacteroides
3. Alternate to tetracyclines for Rickettsial and brucellosis
Term
Absorption and distribution of Chloramphenicol
Definition
Rapid oral absorption and high distribution(lipophilic, crosses BBB placenta, CSF)
Term
Chloramphenicol excretion.
Definition
inactivated by liver glucuronyl transferase(90%) some active drug is excreted VIA urine.
Term
Adverse effects of Chloramphenicol
Definition
Dose related anemia/bone marrow suppression.
Aplastic irreversible anemia (often fatal)
Gray Baby Syndrome
Term
Aminoglycosides spectrum
Definition
Aerobic gram (-) bacilli
Term
Aminoglycosides chemistry and mechanism
Definition
Basic cations can react w acidic penicillins and deactivate each other.
Binds 30S ribosome and causes mRNA misreads. Bad proteins can insert into membrane and destroy membrane integrity.
Term
Aminoglycosides spectrum
Definition
Severe aerobic gram (-) nosocomial infections. Ineffective against anaerobes.
Term
Aminoglycosides 3 mechanisms of resistance
Definition
1. Inactivation by plasmid-mediated enzymes that acetylate, phosporylate or adenylate(Amikacin is less susceptible)
2. Alteration of transport system (energy and oxygen dependent)
3. Mutation in Ribosome that binds drug
Term
Aminoglycosides absorption and distribution
Definition
Poor absorption and only 20% distribution, does not enter CSF or cross placenta
Term
Excretion of Aminoglycosides
Definition
Glomerular filtration. Elderly, neonates and renally compromised are at risk for toxicity.
Term
Aminoglycosides adverse effects
Definition
1. Neurotoxicity: irreversible damage to hair cells in cochlea and vestibule
2. Nephrotoxicity: (proximal tubule) inhibits phospholipases in lysosomes which burst and release hydrolases into the cytoplasm
3. Neuromuscular blockade: respiratory depression(myasthenia gravis and hypoglycemic are susceptible) Antidote: Calcium gluconate or neostigmine
Term
Drug interactions of Aminoglycosides
Definition
Penicillins, nephrotoxic drugs(diuretics, cisplatin, cyclosporine, amphotericin B, and Vancomycin).
Term
What combinations are used against Psuedomonas and some gram (-) nifections
Definition
Aminoglycosides and either penicillin or cephalosporins.
Term
Aminoglycoside prototypes
Definition
Gentamicin (systemically)
Amikacin (systemically)
Neomycin (topical or oral prior to surgery)
Streptomycin (used for TB)
Term
tetracycline prototypes
Definition
tetracycline
doxycycline
minocycline
tigecycline
Term
Mechanism of Macrolides
Definition
Inhibits protein synthesis by binding 50S ribosome. Only bacteriostatic.
Term
Therapeutic uses of Macrolides
Definition
1. Common strep URI
2. H. infl otitis media
3. Pneumonias due to Chlamyophillia, mycoplasma and legionella
4. Bordetella (whooping cough, chronic bronchitis, sinusitus.)
5. H. pylori (clarithromycin)
6. Mycobacterium avium in AIDS patients (Clar/azith)
7. Diptheria carriers
Term
Resistance to Macrolides
Definition
1. Decreased drug penetration through cell envelope
2. Methylation of ribosome target
3. Hydrolysis of drug (enteric gram (-))
4. Ribosome mutation
Term
Macrolides absorption
Definition
erythromycin-acid labile
Clarithromycin-acid stable take w food
Azithromycin-acid stable
Term
Macrolides distribution
Definition
Good into tissue but not CSF.
Azithromycin concentrates in Phagocytes, macrophages and fibroblasts
Term
Macrolides excretion
Definition
E: CYP3A metabolism
A: unchanged in feces t1/2 = 68hrs
C: 30% in urine, remainder in feces
D: t1/2 = 30-44 hrs
Term
Macrolides adverse effects
Definition
E: GI upset, ototoxicity, and hepatotoxicity w estolate ester
Term
Drug interactions of Macrolides
Definition
E and C: inhibit CYP3A4 which can cause build up of carbamazepime, glucocorticoids, cyclosporin, digoxin, theophylline, triazolam, valproate and warfarin.
E: Cardiac arrhythmias and QT prolongation
Term
Macrolide prototypes
Definition
Erythromycin
Clarithromycin
Azithromycin
telithromycin
Term
Sulfonamides are only effective against what kind of microorginisms
Definition
Those that require PABA to synthesize folic acid.
Term
Sulfonamides mechanism of action
Definition
Competively inhibits dihydropteroate synthase, can serve as an alternate substrate causing inactive produts.
Bacteriostatic
Term
Mechanism of trimethoprim
Definition
Blocks dihydrofolate reductase
Term
Sulfasoxazole
Definition
1. Oral sulfamide of choice
2. High water solubility
3. can be combined with erythromycin to treat otitis media or URI's
Term
sulfadiazine
Definition
High CSF levels, therapeutic within 4 hrs, t1/2=10 hrs, problems with crystalluria
Term
sulfamethoxazole
Definition
Similar to sulfasoxazole, longer t 1/2 = 11 hrs due to slower absorption/excretion. More likely to cause crystaluria
Term
TMP-SMX
Definition
Synergistic effect. Net result makes it bacteriocidal.
Term
Sulfasalazine
Definition
Prodrug, Poorly absorbed, broken down into sulfapyridine(active) and mesalamine(COX inhibitor). Treats IBD, ulcerative colitis, and regional enteritis. Absorption of high doses of sulfapyridine can be toxic
Term
Silver sulfadiazine
Definition
Topical, drug of choice for 2nd and 3rd degree burns. Can cause photosensitivity. Preferred over mafenide.
Term
sulfacetamide sodium
Definition
Ophthlamic topical, treats Chlamydia trachomatis
Term
sulfadoxine-pyramethamine
Definition
Pyramethamine is similar to TMP in action, sometimes prescribed for parasites
Term
trimethoprim
Definition
Highly selective for bacterial dihydrofalate reductase
Term
Sulfonamides absorption
Definition
rapid except sulfasalizine
Term
Sulfonamides distribution
Definition
widely distributed, crosses placenta and can be toxic
Term
Sulfonamides metabolism and excretion
Definition
Acetylated in liver excreted by glomerular filtration, so renal function is required
Term
Sulfonamides adverse effects
Definition
1. UTI(crystalluria)
2. Hypersensitivity(rash, erythema multiforme, drug fevers, PT)
3. Hematopoetic (rare, bloody dyscrasias, anemia, contraindicated w porphyria patients)
4. Kernicterus (bilirubin displced from albumin in neonates, also passes in breast milk)
Term
Sulfonamides drug interactions
Definition
Displaces drugs from albumin. Including Sulfonylurea, hypoglycemic drugs, anticoagulants, phenytoin and methotrexate.
Term
TMP-SMX sensitive organisms
Definition
1. Gram (-) bacilli
2. Actinomyces, Nocardia
3. Three parasites (AIDs patients) Cyclospora, Isospora, Toxoplasma.
4. One fungus: Pnuemocystis jiroveci
5. Back up drug for 24 others
Term
TMP-SMX therapeutic uses
Definition
1. Oral Rx for UTI
2. MRSA backup
3. Pneumocystis in AIDs patients
4. URI due to H. flu Strep. P.
5. GI infections (Shigella, Salm., EHEC may increase HUS though)
Term
TMP-SMX Distribution
Definition
Widely distributed
Term
TMP-SMX adverse effects
Definition
1. Hypersensitivity (fever, rash, etc)
2. CNS effects (headache, depression and hallucination)
3. Contraindicated in renal disease
4. Megaloblastic anemia in folate deficient patients.
Term
Methenamine
Definition
Prodrug, decomposes to formaldehyde and ammonia in acidic conditions. Used for chronic cystitis.
Term
Methenamine toxicities
Definition
1. GI (take with food)
2. Contraindicated with renal or liver disfunction
3. Rashes, hematuria, almbuminuria, and painful/frequent micturition
4. Formaldehyde forms precipitates with sulfamethizole
5. Don't use with drugs that Alkanize urine
Term
What bacteria can alkalize urine
Definition
Proteus and Pseudomonas can split urea thus alkalizing urine
Term
Nitrofurantoin
Definition
Reduced by bacteria to products that mediate cell damage. Static at low, cidal at high, needs acidic urine
Term
Nitrofurantoin resistant bacteria
Definition
Klebsiella, enterobacter and those that alkalize urine (Proteus and Psuedomonas)
Term
Nitrofurantoin absorption and excretion
Definition
Rapidly absorped and excreted. never reaches high plasma levels, don't give with probenecid due to toxicicity.
Term
What UTI drugs should never be mixed
Definition
Any methenamine + Any sulfa ▬► An insoluble ppt
Term
Which UTI drug is given with an organic acid? When is this contraindicated?
Definition
Methenamine, renally impaired.
Term
Nitrofurantoin Toxicities
Definition
GI irritation – common N/V.
Pulmonary and hepatic
Term
Nitrofurantoin Toxicities
Definition
Turns Urine brown, contraindicated in pregnancy and with decreased renal function. Can have sensory/nueral problems in which case the drug is discontinued.
Term
Fosfomycin
Definition
Blocks cell wall synthesis by inactivating bacterial enolpyruvyl transferase. Single dose adequate for Cystitis, Effective against many enteric gram (-) organisms but *not useful against Pseudomonas
Term
Phenazopyridine
Definition
An analgesic for symptomatic relief of UTI pain
Term
Fluoroquinolone’s Mechanism of Action
Definition
They target two enzymes needed for replication of double-stranded DNA:
DNA gyrase (Topoisomerase II)
Topoisomerase IV
Term
Fluoroquinolones spectrum and limitations
Definition
Wide spectrum of both Gram + and -.
Limitations:
*Spirochetes are completely resistant
*Anaerobes are mostly resistant: only moderately sensitive to moxifloxacin
*Penicillin-resistant Strep. pneumoniae are mostly resistant
*Resistance is increasing in Staph. aureus and is frequent in MRSA
*Neisseria gonorrhoeae is now likely to be resistant.
Term
Therapeutic Uses of Fluoroquinolones
Definition
*Cipro is #1 for UTIs due to Pseudomonas
*Cipro & levofloxacin are drugs of choice for uncomplicated pyelonephritis
*They are backups to TMP-SMX for commonly occurring uncomplicated cystitis; Bactrim is preferred to minimize development of resistance to FQs.
Term
What drug would be used to treat prostatitis
Definition
Any FQ
Term
What drugs are used to treat travelers diarrhea
Definition
*Cipro or Levaquin are good & preferred to TMP-SMX in adults
*Azithromycin (the FQ backup) is preferred in India, Thailand where Campylobacter is resistant to FQs.
*Bactrim is preferred for TD in kids
Term
Prophylaxis after exposure to meningococcus or anthrax
Definition
Cipro
Term
Toxicities of the Fluoroquinolones
Definition
CNS agitation
*Responses range from headache to seizures (1-10%)
*Inhibits by displacing GABA from CNS receptors.
*Agitation more common in elderly patients.
*Insomnia occurs more often in young children*Prolongation of the QT Interval in the heart*FQs contraindicated in pregnant, nursing mothers & children
Term
First generation FQs to know
Definition
Ciprofloxacin, lomefloxacin
Term
Second generation FQ's to know
Definition
Gemifloxacin, Levofloxacin, Moxifloxacin
Term
Drug Interactions with FQs
Definition
**FQs are very well absorbed (70-100%) in the absence of multivalent cations.
**Antacids, iron, multivitamins, sucralfate (Al), or didanosine (Al, Mg) chelate FQs & decrease bioavailability by up to 90%; must be staggered in dosing by 2+ hr
Term
Two ways to treat TB
Definition
6-month course of treatment that involves 4 drugs for the first 2 months (isoniazid, rifampin, ethambutol, and pyrazinamide),
Followed by isoniazid and rifampin for the remaining 4 months.
Rifampin in combination with isoniazid for 9 months also is effective therapy for strains susceptible to both agents
Term
Isoniazid
Definition
TB, primary drug in all regimens, also prophylaxis
Term
Rifampin
Definition
excellent tuberculcidal drug, most rapid acting, useful for other bacterial infections
Term
What drugs are used when there is resistance to first line TB drugs
Definition
Pyrazinamide and Streptomycin
Term
Clinical problems with TB drugs
Definition
Isoniazid (peripheral neuritis, hepatitis)
Rifampin (hepatic toxicity, GI effects, red-orange urine and tears, flu-like symptoms)
Ethambutol (altered visual acuity and impaired ability to peceive green)
Pyrazinamide (hepatic necrosis, precipitate gout)
Streptomycin (ototoxicity, vestibular toxicity, and nephrotoxicity
Term
Adverse effects of Clindamycin
Definition
Diarrhea* (8%)
potential antibiotic associated colitis (overgrowth of C. difficile)
skin rashes* (10%)
Thrombophlebitis* with IV admin.
Term
Adverse effects of Vancomycin
Definition
Nephrotoxicity*
Ototoxicity* (reversible)
Thrombophlebitis*
Red man syndrome
Term
Adverse effects of metronidazole
Definition
frequent GI disturbances* and metallic taste
Neurotoxicity* (dizziness and vertigo)
blood dyscrasias* or neutropenia
Term
Bacitracin
Definition
Topical, used vs. gram positive cocci
Term
Polymixin B
Definition
used vs. aerobic gram-neg. bacilli
Topical treatment of infections of skin, mucous membranes, eye and ear
Term
Which drug is limited by crystalluria and should be taken with lots of water and bicarbonate. Urine should be >1200 ml per day
Definition
Sulfadiazine
Term
Oncogenes
Definition
ras, EGF receptor, PDGF receptor, BRAF, kit, and abl.
There is a specific treatment imatinib (Gleevec) for kit and abl.
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