#28 Tackett - Antibiotics/Chemotherapy Flashcards
An immune compromised patient would not benefit from which types of drug? Bacteriostatic or Bacteriocidal
Bacteriostatic - patient must have a competent immune system to finish the job.
What adaptations are taking place in bacteria that are leading to resistance?
- Lipopolysaccharide coat is changing which affects the rate at which a drug can be taken up.
- The transport system is altered so the drug is removed from the cell.
- Bacteria change the way the drug is metabolized so that the adverse effect is bypassed.
How do bacteria transmit extrachromosomal genetic elements?
Plasmids and transposons that code for enzymes that inactivate drugs can be transferred to other pathogens or inserted and incorporated into genetic material of pathogen.
Describe the mechanism of action of cell wall synthesis inhibitors.
They compete for the enzymes that catalyze the transpeptidation and cross-linking.
Which cell wall synthesis inhibitors contain a beta lactam ring?
Penicillins
Cephalosporins
Carbapenems
Monobactems
What are the three types of adverse reactions to penicillin and which is the worst one?
Immediate (**worst - within 20 min. wheezing choking, shock, death)
Accelerated (1-72 hours - mainly urticaria)
Late (72 hours to several weeks - mainly skin rashes)
What syndrome can be a side effect of penicillin?
Stevens-Johnson Syndrome (form of TEN - toxic epidermal necrolysis)
Cephalosporin can interfere with which vitamin? and result in?
Vitamin K; increased bleeding
Cephalosporin can block alcohol oxidation leading to what?
acetaldehyde accumulations; toxic reaction, N/V
What non-beta lactam drugs inhibit cell wall synthesis?
Vancomycin
Teicoplanin
Bacitracin (topical)
What is the mechanism of action of non-beta lactam drugs that inhibit cell wall synthesis?
prevent polymerization of the linear peptidoglycans
What dose related toxicity can occur with vancomycin?
Ototoxicity (tinnitus, high tone deafness, hearing loss)
List 3 types of toxicity due to aminoglycosides narrow margin of safety?
- Ototoxicity [ Cochlear - auditory / Vestibular - vertigo]
- Nephrotoxicity (due to rapid uptake via proximal tubular cells)
- Neurotoxicity (due to blockage of presynaptic release of ACh - weakness and respiratory depression)
Where is tetracycline deposited?
bone and teeth
Tetracycline is contraindicated in which type of patient?
pregnant
children
What warning should be given to the patient taking tetracycline?
Stay out of the sun. Tetracycline causes severe photosensitivity.
Your patient has a vancomycin-resistant infection that has been found to be an anaerobic gram-positive organism. The individual has been dealing with the infection for months and it is beginning to affect their mood (slightly depressed). Which oxazolidinone would you prescribe?
Linezolid
A baby is brought in with vomiting and abdominal extension. In addition there is decreased respiration and cyanosis. You believe the baby has Grey Baby Syndrome. What medication has the baby most likely been on and for what reason?
Chloramphenicol
- Broad spectrum antibiotic effective against most anaerobic and aerobic organisms
- NOT for Pseudomonas aeruginosa
- *reserved for life threatening infections
Other than Grey Baby Syndrome, what other side effects can result from Chloramphenicol? Which one is fatal?
- Dose related bone marrow depression
- dose related reversible anemia
- Idiosyncratic aplastic anemia (usually fatal)
Bacteria cannot absorb __________ __________.
Humans cannot ____________ the above material.
Folic acid
synthesize
**Provides for a selective drug target
55 year old man comes in over the weekend to the emergency clinic with an Achilles tendon rupture. He says he was feeling better from his UTI so he decided to play tennis. Due to his age and the tendon rupture you ask him if he is on any medication. You suspect he may have been taking which drug class?
Quinolones (-oxacin)- used for UTIs, lower respiratory tract infections, bone and joint infections and prostatitis.
[The ox was an Ace in tennis]
-oxacin , tendon
A friend of yours on a trip to Texas decided it would be fun to put a beer can in a dead armadillo’s arms. Unfortunately he caught leprosy. The therapy consisted of 5 drugs. One drug caused hepatic dysfunction consisting of elevated hepatic enzymes and hepatitis. Which drug caused these side effects?
Isonazid
Rifampin can also cause hepatitis.
How would you overcome the peripheral neuropathy caused by Isonazid and what is the cause?
Co-administer pyridoxine
Due to pyridoxine deficiency
One of your patients recently began anti-tuberculosis treatment and is on rifampin. What other medications do you need to monitor and why?
Any drug that is metabolized by cytochrome P450 enzyme. Rifampin induces the cytochrome P450 enzyme which may lead to sub-therapeutic effects of other medication.
What side effect of Rifampin should you make your patient aware of so they do not become alarmed?
Colored secretions (urine, saliva, feces, sweat, tears) can be red-orange
Our leprosy friend began to experience loss of his central vision. We suspected he was experiencing optic neuritis from which of his drugs?
Ethambutol
A friend of yours loves to go get pedicures. Unfortunately she got a fungal infection. Which antifungal medication would you prescribe and how would it be administered?
Terbinafine; orally for superficial fungal infections
- could also be used for hair fungi
What is the mechanism of action of Terbinafine?
Inhibits squalene epoxidase causing the squalene to accumulate inside the fungal cell.
You have just returned from a remote part of the South American jungle. You did not take your anti-malarial medication as prescribed and you are now experiencing malarial symptoms. You are tested and sure enough you have hypnozoits, the dormant parasite liver form. What medication would your doctor prescribe?
Primaquine
After taking your primaquine for your malaria, you start to feel fatigued and notice yellowing of your eyes. You go to talk to your doctor. He orders labs and discovers you have hemolytic anemia. He suspects you are deficient in which enzyme?
glucose-6-dehydrogenase
You are also probably male.
Someone comes in to your urgent care facility complaining of impaired hearing, blurred vision, N/V/D and tinnitus. What are these symptoms called and what anti-malaria medication can cause them?
Cinchonism
Quinine
A mother brings her child in with flu-like symptoms. You take a patient history and discover that these symptoms have been going on for four days. Will you prescribe Oseltamivir and why or why not?
No prescription. Anti-influenza drugs must be administered within 48 hours.
Try some OMM! :)
