40-ABX Quinolones, Antifolate Drugs, and Sulfonomides Flashcards
What are the two categories of Antifolate drugs
- Sulfonamides- work by inhibiting the synthesis of dihydrofolate in some bacteria and parasites.2. Folate Reductase Inhibitors- block the action of dihydrofolate reductase and formation of tetrahydrofolate in various organisms (kills protozoa, bacteria and mammalian cells)
Examples of Antifolate drugs
SulfamethoxazoleTrimethoprimTrimethoprim-Sulfamethoxazole (SMZ/TMP) (Bactrim, Septra) Silver SulfadiazineSulfacetamide
Which is the main work horse drug of sulfonamides?
Bactrim- -tolerated well orally, widely distributed to tissue and cross the BBB-Hepatically metabolized and excreted in urine
What do you caution patients taking sulfonamides (since its excreted in urine)
without adequate hydration will cause crystalluria. Patients need to drink enough water. Can be given IV/orally but still need proper hydration
Name some of the drug classes often used to treat UTI and other infections
SulfonamidesTrimethoprimFluoroquinolones
Why do we give immunosuppressed patients bactrim?
To prevent PCP pneumonia. Drug of choice to treat PCP PNA
What is the dose ratio of SMZ/TMP
- 5:1 ratio synergistically - Double Strength: (DS, 800mg/160mg) - Single Strength: (SS, 400mg/80mg) and we dose off TMP and not SMZ
What sulfa drug is used to treat burns
Silver Sulfadiazine
Which sulfa drug is used to treat ocular infections
Sulfacetamide (Blep10)
Give some of the ADR’s of Sulfonamides?
Skin rash that can progress to Steven Johnson’s, crystalluria, GI distress, Hepatitis, Hematopoietic toxicity, in G6PD they can cause hemolytic anemia, photosensitivity
Which bacteria is sulfonamides not active against?
Pseudomonas (Gram-negative aerobic gammaproteobacteria)But can be active against MRSA
Bactrim is Highly plasma protein bond, so what do you have to worry about?
ASA and Warfarin
Is Bactrim beneficial to CHF patients?
No, especially when given IV, it requires large volumes of fluid to dissolve the drug. not helpful for fluid restriction on CHF pts
What are some ADR’s of Bactrim?
Megaloblastic anemia with low folic acid, rash, photosensitivity
What patient populations do you have to worry about with bactrim?
- Infants less than 2 months old- Pregnant women and nursing mothers- More skin rashes associated with HIV patients
What are fluoroquinolones and name a few?
These are broad spectrum tidal drugs e.g Ciprofloxacin, ofloxacin, levofloxacin
What is Cipro active against
The original fluoroquinolone is primarily active against gram negative bacteria while new drugs like levofloxacin can cover both gram +ve and -ve bacteria
Why is it necessary to dose fluoroquinolone on an empty stomach?
When take orally, they bind to Ca+, Fe and Mg, thus decreasing its availability or effectiveness
Where are fluoroquinolones metabolized and excreted?
Hepatically metabolized and renally excreted
Combination of Cipro and Ofloxacin is good for treating what?
Pseudomonas
What is the main stay quinolone for anthrax?
Cipro- Also active against MAC, CAP and multi-drug resistant TB
What are some of the ADR’s of Quinolones
- Photosensitivity- Tendonitis and tendon rupture- Problems with long bone formation of children and should not be used in patients <18yrs- Alterations in serum glucose- seizures- QT prolongation- inhibit caffeine and theophylline metabolism
What are some of the other antibacterial drugs in this class?
Nitrofurantoin, Daptomycin, Polymycin B, Rifaximin, Fidaxomicin
What is the spectrum of Nitrofurantoin?
Orally given and rapidly excreted in urine and used for uncomplicated UTI in women. Should be taken with food to increase absorption and decrease GI distress
