Sulfonamides and Potentiated Sulfonamides Flashcards
Are Sulfonamides bacteriostatic or bactericidal?
Bacteriostatic
Sulfonamides are one of the first antimicrobials to be used on a widespread basis, which has caused bacteria to become what to them?
Many strains of bacteria have become resistant to them
Sulfonamides are potentiated with what to potentiate their antibiotic effects & convert them from bacteriostatic to bactericidal?
Trimethoprim & Ormetoprim
What is Sulfadimethoxine combined with and what drug is it found in?
Combined with Ormetoprim and in the drug Primor
What is sulfadiazine combined with and what drug is it found in?
Combined with trimethoprim in the drug Tribrissen
Sulfasalazine is found in what drug and what is it used for?
Azulfidine and it is used for its antiinflammatory properties to treat IBD
Sulfonamides can be described as what in reference to the location of their site of action?
Enteric or Systemic sulfas
Which sulfa has a site of action within the intestinal tract, designed to not be absorbed into the body and Sulfasalazine is an example?
Enteric sulfas
Which sulfa is intended to be absorbed from the intestinal tract into the body?
Systemic sulfas
What is Sulfamethoxazole combined with and what drug is it found in?
Combined with Trimethoprim in the human drug Septra or Bactrim
What are the potentiating compounds?
Trimethoprim and Ormetoprim
What is the mechanism of action for sulfonamides?
They inactivate a key enzyme involved in the synthesis of folic acid
The spectrum of action for potentiated sulfonamides is broad and includes what?
Gram-positive bacteria
Gram-negative bacteria
Protozoa organisms
Which sulfonamide is not commonly used for its antimicrobial effect but its antiinflammatory effect in the colon to treat colitis?
Sulfasalazine
When sulfasalazine is given orally only 1/3 is absorbed. What happens to the rest?
Stays in the bowel where it is transformed by colonic bacteria into an aspirin-like antiinflammatory drug
When sulfasalazine is transformed into an aspirin-like antiinflammatory drug how does that benefit the colon?
It inhibits prostaglandin formation which decreases colonic inflammation and hypersecretion associated with large bowel inflammatory disease
Sulfonamides and their potentiated forms are well absorbed in what in dogs and cats? What is the exception to this?
GI tract
Enteric sulfaonamide sulfasalazine
What sulfonamide component may be trapped and degraded in the rumen of ruminents, reducing the amount absorbed?
Trimethoprim component
The oral absorption for horses and ruminants varies a great deal based on what?
Diet and age
Sulfonamides can readily traverse through which systems?
Prostate gland
Cross the placenta
Pass into the milk
Due to what characteristic of sulfonamide allows it to penetrate the blood-brain barrier and achieve significant concentrations in the CNS and Cerebral spinal fluid?
Lipophilic nature
Why are sulfonamides used to treat UTIs?
They are filtered by the glomerulus and actively secreted into the renal tubules achieveing high concentrations in urine
What is the reason some clinicians administer trimethoprim-sulfonamide BID instead of the recommended SID?
The bacteriocidal effect of sulfonamide and its potentiating compounds will only be achieved if they penetrate the infection site together
What is one of the more common reactions to Sulfonamides?
Decreased tear production resulting in Kertaoconjunctivitis sicca
How do you treat Keratoconjunctivitis sicca?
Cyclosporine ophthalmic ointment (Optimmune)
Dogs must be treated for the rest of their lives
What do skin reactions to the drug look like?
Pruritus
Swelling of the face
Hives
What do hypersensitivity reactions to Sulfonamides look like?
Manifest as liver necrosis
Liver failure
What breed of dog are more susceptible to hypersensitivity reaction to Sulfonamide?
Doberman pinschers
What other reactions do Sulfonamides cause?
Thrombocytopenia
Leukopenia
Aneima
Crystalluria (damage renal tubules)
What sulfa can produce salicylate toxicity (Aspirin toxicity) in cats?
Enteric sulfa sulfasalazine
