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Pharmacology > week 4: Anti-infective_ Protein synthesis Inhibitors > Flashcards

week 4: Anti-infective_ Protein synthesis Inhibitors Flashcards

1
Q

Tetracyclines Class​/Clinical Indications​

A

Active against gram (+), gram (-), and atypical organisms

Typically, bacteriostatic

1st class of antibiotics to be labeled “broad-spectrum”

Alternatives to beta-lactams​
Acne vulgaris​
CAP​
MRSA (doxy & minocycline)​​

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2
Q

Tetracyclines Pharmacokinetics​

A

–Absorption improved on empty
Stomach
–Food ↓ absorption along with milk /
dairy​ Exception: Doxycycline​

  --Phenytoin and carbamazepine 
          ↓ half -life of doxycycline​
Drug Interactions​
      --Antacids​
      --Iron​
      --Cholestyramine​
      --Sucralfate​
      --Tetracycline potentiates the effect of  
         warfarin by impairing vitamin K
         production by the intestinal flora​
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3
Q

Tetracyclines SE and drawbacks

A

Hepatotoxicity: rare but potentially fatal​
–Increases with use with other
hepatotoxic agents​ and expired
tetracyclines
Grey-brown discoloration of teeth (permanent)​
–Contraindicated in children
< 8 years of age​
Tinnitus
Phototoxicity with tetracycline​
Dose-related vertigo: minocycline​
Nephrotoxix-> Faconi syndrome

Cross placenta; Chelating effect, binds with Ca++ → discoloration of deciduous teeth, enamel hypoplasia, inhibition of fetal skeletal growth.​

Greatest risk: middle of 2nd trimester through 6 months of age​
Excreted in breast milk in high concentrations

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4
Q

Aminoglycosides Class​/Clinical Indications​

A

Bactericidal​: Reserved for treatment of serious, resistant G-negative infection​
including pseudomonoas
Not normally used in primary care​
Narrow therapeutic window​
Not effective for anaerobes
Oral preparations: Suppression of bacterial flora​, tx for hepatic coma

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5
Q

Aminoglycosides pharmacokinetics

A

Cross the placenta, but distribution into breast milk is unknown​

Patients with impaired renal function are at increased risk for toxicity​
Oral aminoglycosides are not absorbed​
       --Only use is for suppression
         of  intestinal bacteria​
       --IM and IV use for treatment​
Serum peak (30-45 minutes after IV dosing; 60 minutes after IM) Trough (drawn immediately before dosing) ​
Should be monitored after second or third dose ​
Every 3-4 days, thereafter for duration of therapy
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6
Q

Aminoglucosides SE / Drawbacks​​

A

Nephrotoxicity : Acute tubular necrosis, reversible
Ototoxicity,: High frequency loss first. Not reversible
Neuromuscular blockade​
Teratogenic

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7
Q

Macrolides/Ketolides Class​/Clinical Indications​

A

​Bacteriostatic
Gram (+) and Gram (-) aerobes
Atypical organisms: chlamydia, mycoplasma, legionella, rickettsia, mycobacteria, spirochetes

Whooping cough (Pertussis)
Typical and Atypical pneumonia 
Not recommended for
          Acute bacterial Sinusitis
          (even in patients with
           allergy to b-lactams) due
           to increasing resistance​
STIs​ (Azithro)
Ulcer by  H pylori (clarithro)
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8
Q

Macrolides/Ketolides Pharmacokinetics​

A

Minimal protein binding
Good tissue penetration
Improved GI profile and longer half-lives​ with azithro and clarithro
Half-lives vary: 2 hours –60 hours

Erythromycin compatible with breastfeeding
No alternate birth control method is required

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9
Q

Macrolides/Ketolides SE/Drawbacks

A

Clarithromycin​
–Ototoxicity​ with extremely high
dose
–Psychosis
All except azithromycin​
–Potent inhibitors of CYP 3A4
isoenzyme pathway​
–Prolong half-life of cyclosporine,
carbamazepine, theophylline, warfarin
& HMG-CoA reductase inhibitors
(statins)​
All have potential to increase QT interval​
–Caution when using other agents that
prolong QT interval​

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10
Q

what dose of Erythromycin ethylsuccinate = to what erythromycin base?

A

Due to differences in absorption, 400 mg erythromycin ethylsuccinate = produces the same serum levels as 250 mg erythromycin base or stearate.

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11
Q

True or false, in Azithromycin, ER suspension (Zmax) is not interchangeable with IR formulations.

A

true

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12
Q

Lincosamides Class​/Clinical Indications​

A

Gram (+) & anaerobic infections​
Concentration dependent killing

Reversible binding to
50 S ribosome subunits

May be combined with gentamicin to treat mixed aerobic and anaerobic infections​

Infections (osteomyelitis and Group A strep, septic arthritis, postpartum endometritis, skin and soft tissue infection more)
Acne
Taste bitter: not for children

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13
Q

Lincosamides Pharmacokinetics​

A

Well absorbed and 90% bioavailable​

Penetrates most tissues (including abscesses) & bone ​

Limited CSF​
93% protein-bound​

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14
Q

Lincosamides SE / Drawbacks​​

A

N/V/abdominal pain​
Associated C. difficile colitis (Pseudomembranous colitis)
Metallic taste with IV

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15
Q

What is Fluoroquinolones

A

Bind to these enzymes and interfere with DNA ligation Increases the number of permanent chromosomal breaks, triggering cell lysis

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16
Q

Fluoroquinolones Class​/Clinical Indications​

A 
Bactericidal: concentration-dependent​
oAll have gram (-) activity​: Enterobacteriaceae, H. flu, Legionella, Neisseria. Pseudomonas
o
oNewer FQs have gram (+) coverage​
 	--Levofloxacin,
   	moxifloxacin, gemifloxacin​
 	--Referred to as “respiratory FQs”​
 	--Indicated for Streptococcus
   	pneumoniae​
 	--Less effective against pseudomonas
oNo effective for  MRSA
o
oUTI: NO longer agent of choice for acute uncomplicated cystitis d/t resistance​
oProstatitis​
oPneumonia​/Nosocomial pneumonia​
oSTIs​
oSkin & soft tissue​
oGI: combine with an agent covering anaerobic​
oTravelers diarrhea​
oOsteomyelitis​
17
Q

Pharmacokinetics​ Fluoroquinolones

A 
oExcellent bioavailability​
-- Antacids, sucralfate, Mg,Ca++, or Iron salts​  by chelation
 --Decrease absorption of FQs​
oHalf-life: range 4 – 12 hours​
oRenal excretion​
 --Exception: moxifloxacin​
oNot recommended for nursing moms
18
Q

What are the two distinct topoisomerases are needed for bacteria to replicate in numbers

A

DNA gyrase (topoisomerase II)
–Responsible for reducing torsional stress ahead of replicating forks by breaking double-strand DNA and introducing negative supercoils
Topoisomerase IV
–Separate daughter chromosomes once replication is completed

19
Q

What is the black box warning for Fluoroquinolones?

A

Irreversible tendinopathy, tendon rupture, peripheral neuropathy,
exacerbation of myasthenia gravis

20
Q

What does Rifampin do?

A

Inhibitors of RNA Functions or Synthesis:
Bactericidal for both intracellular and extracellular mycobacteria
M. tuberculosis, Mycobacterium avium complex (MAC), M. Leprae
Used as part of treatment for several different bacterial infections
Never given as a single agent in the treatment of active tuberculosis.
Due to resistant strains rapidly emerge during monotherapy
Mechanism of action
Blocks RNA transcription by interacting with the β subunit of mycobacterial DNA-dependent RNA polymerase.

21
Q

What is the Class​/Clinical Indications​ for Rifampin

A 
Bactericidal :
oGram (+) cocci​ :
   	--Mycobacterium tuberculosis​
   	--Staph aureus
oModerate activity against gram (-)
  	-- Neisseria meningitidis​
  	--Neisseria gonorrhoeae​
  	-- H. influenzae​
o1st-line treatment for Active & latent TB​
   	---RIPE (rifamycin (like rifampin), isoniazid,
       	pyrazinamide, and ethambutol)
o
o
oCombined with other agents
         	for MRSA​ or  serious gram (+)
          	infections that fail to respond to other tmt​
          	for synergistic activity to prevent resistance
​
22
Q

What is the Pharmacokinetics​ for Rifampin?

A

Well absorbed through GI tract​
oPenetrates most tissues/fluids including CSF​
oHalf-life: 3 hours​
oMetabolized by liver​ and renally excreted
oOK in pregnancy

23
Q

What is the SE and drawback for Rifampin?

A 
GI: N/V/D​
oHeadache​
oFever​
oChanges bodily fluids to a red-orange color​: harmless
oRisk of hepatotoxicity when combined with isoniazid (INH)​
       	-- stop when  3 x>  and sx or  5x  >
           	with no sx
oAnemia ​
oThrombocytopenia​
o
Drug Interactions​
oPotent inducer of CYP enzyme pathways​
   	--Antiarrhythmics​
   	--Azole antifungals​
   	--Clarithromycin​
   	--OCP
   	--Most HMG-CoA reductase inhibitors​
   	--Warfarin​
   	--Antiseizure
   	--HIV medications​
24
Q

What is Folate Antagonist

A

Inhibitors of Metabolism:
Folic acid
A coenzyme essential in the synthesis of ribonucleic acid (RNA), DNA, and certain amino acids.
No proper growth of cell without folate synthesis

Pharmacology (4 decks)

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