Basic principle of Trimethoprim & Sulfamethoxazole
Inhibit Folic Acid Production
- bacteria need folic acid and cannot absorb it like humans so they have to manufacture it themselves
- These drugs block bacteria from being able to make Folic Acid
—– blocks the first enzyme needed produce Folic Acid
—– blocks the second enzyme needed to produce Folic Acid
They are a —– punch
Sulfamethoxazole
Trimethoprim
1-2 punch
Without — —-, bacteria cannot function (make RNA, DNA).
Folic Acid
What are some common uses for Trimethoprim/Sulfamethoxazole?
- Skin Infections (including MRSA)
- Uncomplicated UTIs
Trimethoprim/Sulfamethoxazole drugs are created with a —- ratio.
1:5 ratio
1 Sulfamethoxazole for every 5 Trimethoprim
What is one issue with SMZ/TMP for CHF patients?
the drug doesn’t dissolve in water well, so the IV bag is huge and can lead to FVO for a weak heart
Big 3 Allergy Meds?
- PCN (Penicillin)
- Sulfonymides (Sulfa-)
- NSAIDS
watch for allergic reactions w/ these drugs
Side Effects for SMZ?
- Hypersensitivity
- Hemolytic Anemia
- Kernicterus
- Renal Injury
Side Effects for TMP?
Hyperkalemia
so no ACE Inhibitor, ARB, or Spironolactone
SMZ/TMP has a risk for which serious rash?
Steven Johnson’s Syndrome
Stop taking if rash develops
What causes the risk for renal injury w/ SMZ/TMP?
hard to dissolve so it precipitates in the kidney
Who is most at risk for the Hemolytic Anemia caused by SMZ/TMP?
African Americans and people of Mediterranean descent
What should we teach a patient who is taking SMZ/TMP?
Drink lots of water (8-10 glasses a day) b/c it takes a bunch of water for it to dissolve
Why can SMZ/TMP cause brain damage?
It is highly protein bound and can know bilirubin off, causing it to collect in the brain
This is Kernicterus (literally ‘Jaundice of the Nucleus [Brain]’
Who should not receive SMZ/TMP?
Infants younger than 2 months and pregnancies after 32 weeks or mothers who are breastfeeding
Why?
b/c of risk of Kernicterus in the developing brain
Why use SMZ/TMP together?
They potentiate each other’s effects
1-2 punch
How many versions of SMZ/TMP drug?
two
SS = single strength DS = double strength
TMP specifically causes you to build up which electrolyte?
K+, leading to hyperkalemia
What is the mortality rate for Steven’s Johnson?
25%
SMZ/TMP specifically can cause this
STOP if you see a rash
