Term
| Name the main uses of penicillin G |
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Definition
Groups A, B, C, and G streptococci
Syphilis |
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Term
| What is thought to be the mechanism behind allergic reactions to penicillins? |
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Definition
| The inactive form, penicilloic acid, is thought to form haptens with proteins in the body to cause an immune response. |
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Term
| Why does nafcillin not require adjustment in renal dysfunction? |
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Definition
| Nafcillin is primarily excreted via biliary excretion. |
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Term
| What are the main uses of nafcillin? |
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Definition
MSSA
B-lactamase-producing staphylococci |
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Term
| What are the main uses of oxacillin? |
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Definition
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Term
| Can amoxicillin and ampicilin be given via continuous infusion? |
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Definition
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Term
| What are the main uses of amoxicillin? |
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Definition
| MSSA when in combination with clavulanate |
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Term
| What are the dosage strengths of the amoxicillin/clavulanate combination? |
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Definition
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Term
| What are the main uses of ampicillin? |
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Definition
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Term
| What are the main uses of carbenacillin? What dosage form? |
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Definition
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Term
| What are the main uses of piperacillin? |
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Definition
Pseudomonas
MSSA, H influenzae, M cattarhalis, Klebseilla, and anaerobes with tazobactam |
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Term
| What generation is cefazolin? What are its uses? |
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Definition
| Cefazolin is a first generation cephalosporin often used for surgical prophylaxis covering MSSA, streptococcis, E coli, and Klebisella |
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Term
| What is the main bacteria that is intrinsically resistant to cephalosporins? |
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Definition
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Term
| What cephalosporin is the equivalent to cefazolin and in the same generation? What dosage form? |
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Definition
| Cephalexin in oral form is also good for MSSA, streptococci, E coli, and Klebsiella |
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Term
| What generation is ceftriaxone? What are its main uses? |
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Definition
| It is a third generation cephalosporin and used for MSSA. It is the drug of choice in penicillin resistant strepococcus pneumoniae. |
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Term
| Does ceftriaxone require renal adjustment? |
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Definition
| No, it is primarily biliary excretion. |
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Term
| What is the DOC for Burkholderia pseudomallei? |
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Definition
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Term
| What are the main uses of cefotaxime? What generation is it? |
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Definition
| It is a third generation cephalosporin used for B fragilis and penicillin resistant streptococcus pneumoniae |
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Term
| What drug can treat Burkholderia pseudomallei and P aeruginosa? |
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Definition
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Term
| What generation is cefepime? What are its main uses? When would it be administered TID? |
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Definition
| It is a fourth generation cephalosporin and used for MSSA and P aeruginosa. When treating P aeruginosa, its dosing is increased from BID to TID. |
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Term
| What is the only cephalosporin capable of treating MRSA? What form and salt is available? |
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Definition
| Fifth generation ceftaroline is the only cephalosporin capable of treating MRSA. It is available only as an IV form and comes in a fosamil pro-drug form for solubility. |
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Term
| What does ceftaroline have increased binding to? |
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Definition
| It has increased binding to PBP2a, which mediates MR, making it possible to treat MRSA. |
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Term
| What is the first drug formulated in carbapenems? |
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Definition
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Term
| What are the uses of imipenem, meropenem, and doripenem? |
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Definition
| Imipenem, meropenem, and doripenem are effective against MSSA, B fragilis, and Pseudomonas |
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Term
| Which of the carbapenems must be in a combination? What is the other required drug? |
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Definition
| Imipenem must be given with cilastatin in order to avoid degradation via dehydropeptidases in the renal tubules. |
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Term
| What specific type of B-lactamases are carbapenems not resistant to? |
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Definition
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Term
| Which of the carbapenems do not affect Pseudomonas or Enterococcus species? |
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Definition
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Term
| What is the half-life of Ertapenem? Why is this important? |
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Definition
| The half-life is 4 hours, allowing ertapenem for a once daily dosing. |
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Term
| What class of drug is aztreonam? What is its spectrum of action and most important affected bacteria? |
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Definition
| It is a monobactam and only effective against gram-negative bacteria. It's most known target is Pseudomonas. |
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Term
| A patient's fluid sample returns positive for Pseudomonas. Checking the PMH, the patient has had a reaction to penicillins, which caused her to break out in hives six years ago. Three years ago, patient also had a reaction to ceftazidime. What drug that is not a cephalosporin or penicillin would you definitely avoid knowing the patient's past history despite being a choice for treating Pseudomonas? |
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Definition
| Aztreonam because of the similar side chains to Ceftazidime. |
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Term
| A culture returns gram positive and negative for coagulase. Under microscopic examination, the technician can see clusters of round microorganisms. What would be the drug of choice for this patient? You give this drug without waiting for susceptibility data. What is the reasoning for this? |
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Definition
| Vancomycin is the drug of choice for coagulase negative staphylococci species. 90% of these species are penicillin resistant. |
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Term
| What are the main uses of vancomycin? |
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Definition
| It is used to treat coagulase negative staphylococci species, MRSA, and penicillin/macrolide resistant streptococci pneumoniae. |
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Term
| A patient has been many cramps and diarrhea. When his fecal sample is tested, the presence of C difficile was detected. You recommend oral vancomycin to the doctor, but he disagrees. Who is right and why? |
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Definition
| Oral vancomycin has 0% bioavailability and would not be used to treat systemic infections. However, the patient has an infection in the GI tract (colitis, to be specific). This drug would be appropriate. You proceed to punch the doctor in the face. |
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Term
| After some blood from the patient was taken for use in culture tests, you can see "golden grapes" formations under the microscope. When the coagulase test comes back positive, you highly suspect S aureus and proceed to treat patient with vancomycin. A day later, when the susceptibility test results are back, you notice that this particular strain is susceptible to oxacillin. Is there anything you need to do? If so, what would you suggest? PMH indicates patient has had a rash when he took penicillin for strep throat two years ago. |
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Definition
| Penicllins are better drug treatments for MSSA than vancomycin. However, because of his rash, cefazolin, ceftriaxone, or cefepime would be more appropriate choices. |
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Term
| John is a 78 year old male who was recently hospitalized for sepsis. The culture tests and susceptibility tests suggest he is infected with MRSA. The doctor orders IV vancomycin 1g IV q8h. One hour after initiation, John experiences decreased BP and a HR of 103 bpm. His face is flushed. While the doctor is trying to figure out what is going on, you take a look at today's nursing notes and find that the nurse infused the 1g in 15 minutes. Explain to the doctor what is going on. How could this have been prevented? |
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Definition
| John is experiencing Red Man syndrome because of rapid vancomycin infusion, which caused massive histamin-release. This could have been prevented if the nurse had infused over at least one to two hours or if the doctor had prescribed an antihistamine before initiation. |
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Term
| Of the glycopeptides, which drug has an additional mechanism of action? What is it? |
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Definition
| Telavancin can also disrupt cell membrane potential and increase permeability in addition to inhibition of cell wall synthesis. |
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Term
| Sally is allergic to penicillins, cephalosporins, and macrolides. However, today she was admitted to the hospital for a skin infection. The tests show gram positive bacteria. The doctor suggested vancomycin, but Sally refused after recalling her grandma having "some accident" with vancomycin. A P1 intern suggests telavancin, and Sally is convinced that this drug is the best choice because it is a newer drug. She says that she wants the best for her baby. You immediately tell why she cannot take this drug. What is the reason? |
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Definition
| Telavancin is teratogenic and requires registration in the REMS program along with pregnancy tests. |
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Term
| When would it be effective to give an aminoglycoside alone? When would it not? |
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Definition
| It would be good for an UTI. However, because of poor lung penetration, acidic conditions in the lungs, and low oxygen tension, it should not be used alone in pneumonia. |
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Term
| Which class of drugs are dependent on oxygen-dependent transportation? |
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Definition
| Aminoglycosides such as gentamicin and streptomycin |
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Term
| Order the aminoglycosides by decreasing strength agasint gram negative organisms and P aeruginosa |
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Definition
| Amikacin > Tobramycin > Gentamicin |
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Term
| Why are aminoglycosides ineffective against gram negative anaerobes? |
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Definition
| These bacteria do not use oxygen, so there is no oxygen-dependent transportation for aminoglycosides to enter cells. |
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Term
| What is streptomycin used more for in comparison to the other aminoglycosides? |
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Definition
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Term
| Besides nephrotoxicity, what other side effect is of great concern in aminoglycosides? What other class of drugs share this side effect? |
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Definition
| Ototoxicity is a great concern. Vestibular disturbance is a serous side effect. Ototoxicity also occurs in glycosides. |
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Term
| What is the main reason tetracyclines are not given to children? |
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Definition
| Tetracyclines can chelate calcium phosphate in bones and teeth to stunt growth, deform bone, or discolor teeth. As children are stil growing, they should not be given tetracycline. |
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Term
| What are the main uses of doxycycline? When is it the drug of choice? |
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Definition
| It is used in penicillin-resistant strepococci pneumoniae, CA-MRSA, CAP. It is the drug of choice for CAP (community-acquired pneumonia). |
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Term
| Why is photosenstivity a possible side effect of tetracyclines? |
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Definition
| Formation of free radicals can occur with light excitation, especially in dimecocycline, which as a chlorine ion at C7. |
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Term
| What is the main use of minocycline? |
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Definition
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Term
| Which of the tetracyclines has a black box warning? What is the warning? Why is it still around? |
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Definition
| Tigecycline is the newest and has a black box warning for all-cause mortality increase in patients. However, it is unique for its activity against multi-drug resistant Acinetobacter species. |
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Term
| Which two types of bacteria is tigecycline ineffective against? |
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Definition
| Pseudomonas and proteus species |
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Term
| How does erythromycin cause cramping? |
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Definition
| Erythromycin's lactone ring contains a ketone (C=O) and two adjacent alcohol groups (OH) that can undergo ketal formation in acidic conditions. This ketal formation increases motility of the GI tract. |
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Term
| What are the key uses of clarithromycin? |
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Definition
| CAP, mycobacterium avium-intracellularae (MAI), and H pylori |
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Term
| What are the key uses of azithromycin? |
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Definition
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Term
| Billy comes into the pharmacy today complaining of myalgia and brown urine. He tells you this has happened since his last visit to the doctor for GERD. The doctor had prescribed him some clarithromycin for his H pylori infection, which he started two weeks ago. You look up his Rx profile and notice that he has been taking simvastatin 40mg for years without any side effects. What could be causing this now? |
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Definition
| Clarithromycin is a strong CYP450 enzyme inhibitor, which caused his simvastatin levels to increase by 1000% AUC. This could have led to his myalgia and brown urine, which suggests rhabdomyolysis. You direct him to the hospital immediately. |
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Term
| What are the different CYP450 inhibition effects of the macrolides? |
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Definition
Erythromycin - strong
Clarithromycin - strong
Azithromycin - weak |
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Term
| Azithromycin is the drug of choice for what kind of infections? What other drug shares this status? |
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Definition
| Penicillin resistant streptococcus pneumoniae along with ceftriaxone |
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Term
| Why do azithromycin and clarithromycin not undergo ketal formation like erythromycin? |
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Definition
| Azithromycin has a N atom replace one of the hydroxyl groups while clarithromycin has a methyl group attached to one of the oxygen atoms. |
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Term
| Which of the macrolides has an active metabolite? What is it? |
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Definition
| Clarithromycin can be changed into 14-hydroxyclarithromycin, which still has activity. |
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Term
| Why is azithromycin once daily dosing? |
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Definition
| It penetrates most tissues and phagocytic cells at 10-100x serum levels and is released slowly with a half-life of 3 days. |
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Term
| A new resident at the hospital has been excited to prescribe antibiotics to his patients. He is firm believer in synergistic drug combinations. When a patient comes in CAP that is penicillin resistant, he prescribes azithromycin and chloramphenicol. Tell him this is a good or bad idea and why. |
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Definition
| Chloramphenicol and macrolides share similar binding sites on the 50S ribosomal subunit. Thus, rather than synergistic activity, the two drugs will compete and decrease the efficacy of both drugs. |
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Term
| What is the main degradation mechanism of chloramphenicol? How does this relate to infants? |
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Definition
| Glucoronic acid conjugation is the main mechanism of inactivating chloramphenicol. Infants do not have good glucurodination, so they are at risk for Gray Baby syndrome. |
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Term
| What are the uses of clindamycin? |
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Definition
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Term
| How can clindamycin cause diarrhea? How is this problematic when diagnosing side effects? |
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Definition
| Clindamycin itself can cause diarrhea as a chemical compound, but it can also kill normal gut flora, allowing opportunistic C difficile to invade the GI tract. This will also lead to diarrhea, making it difficult to figure out which one. |
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Term
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Definition
| The D-test shows inducible resistance to clindamycin by S aureus. An agar plate with half erthromycin and half clindamycin will show a characteritisitc D shape of no colony growth. The D shape shows that the S aureus treated with erithromycin are more resistant to clindamycin due to inducible mechanisms. |
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Term
| What is the ratio of quinupristin-dalfopristin? |
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Definition
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Term
| When administering quinupristin-dalfopristin, what do you need to remember? |
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Definition
| Central line only with D5W only |
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Term
| What are the uses of quinupristin-dalfopristin? |
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Definition
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Term
| Smith has been taking a new antibiotic lately, but cannot remember the name. However, he's been feeling a lot of muscle pain. You check his prescriptions and note that he is not on a statin. Just in case, you decide to do a CPK test and find that he is WNL. Which antibiotics could be causing this? How do you differentiate the two? |
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Definition
| Quinupristin-dalfopristin can cause myalgias without CPK elevation while daptomycin will cause elevation. |
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Term
| What type of bacteria is quinupristin-dalfopristin bacteriostatic rather than bactericidal? |
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Definition
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Term
| Which drug is possibly GISA/GRSA effective? |
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Definition
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Term
| Why do we need to monitor platelet count with linezolid? |
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Definition
| It has hematologic side effects. Thrombocytopenia is the most common side effect, especially after two weeks. |
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Term
| If a patient is on an older generation anti-depressant, what should we be concerned about when giving linezolid? |
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Definition
| If the anti-depressant is a SSRI, serotonin syndrome can occur with linezolid. |
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Term
| Linezolid is time-dependent. Explain what time-dependent means. |
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Definition
| Time dependent means that efficacy is more dependent on the frequency of the dosing rather than the dosage amount. |
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Term
| What percentage of CA-MRSA does TMP/SMZ cover? |
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Definition
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Term
| If a patient has pneumonia, what drug should you always avoid? |
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Definition
| Daptomycin because of "hapten" like formation to lung surfactant |
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Term
| What type of bacteria is ciprofloxacin not effective against? |
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Definition
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Term
| When is levofloxacin the drug of choice? |
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Definition
| Penicillin and macrolide resistant streptococci pneumoniae. It is also preferred for multi-drug resistant TB. |
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Term
| Other than penicillin/macrolide reistant streptococci pneumoniae and multi-drug resistant TB, what is levofloxacin commonly used for? |
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Definition
| CAP, HAP, P aeruginosa, S pneumoniae (ciprofloxacin is ineffective to this) |
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Term
| What is one concern in patients with heart rhythm problems when given fluoroquinolones? |
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Definition
| QT prolongation, which can lead to TdP |
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Term
| Although fosphomycin tromethamine is not as good as other oral antibiotics, what is one advantage of this drug? |
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Definition
| It is pregnancy class B and has activity against some strains of pseudomonas. |
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Term
| What is the only indication of nitrofurantoin? |
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Definition
| UTI use only including VRE-cystitis and urethritis |
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Term
| What uses do metronidazole have? |
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Definition
| It is active against anaerobes such as B fragilis and may be used to treat mild C difficile. |
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Term
| Why should a patient not drink and take metronidazole? |
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Definition
| Metronidazole inhibits alcohol dehydrogenase. |
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