Pharm 2 - Antimicrobials 2

drraythe's version from 2015-09-10 15:07


Question Answer
Spectrum of sulfas?Broad
*Cidal or static?Static (mac dipped lin in the pool W/ chorline & made 4 times more SULFUR, I want to STOP going there!)
What is the killing kinetics? (Type _________), which is?Type 2, Time-Dependent (2 took a long sulfur-mud bath)
Distribution of sulfas?WIDE distribution, incld distributed into synovial fluid, aqueous humor & cerebrospinal fluid, Placental transfer
What enzyme are sulfas rendering useless?Dihydropteroate Synthase (DHPS) (they replace the PABA this enzyme is trying to convert)
Works on what Type of bacteria?Aerobic (after a sulfur fart, you will need some air!!)
**What is the mechanism of sulfas? (How do they work)Structural analog of PABA: takes place of PABA (agonist) so bacteria cant make folic acid
What should you do w/ sulfas if you are giving them IV/SQ?Buffer them
**What is the solubility of sulfas & how does this impact them?Fairly H2O INsoluble (upon dehydration, Sulfonamides precipitate & cause crystal formation)
How are the pKa & the penetration related?↑ pKa = ↑ penetration (bc body is SLIGHTLY alkaline, so closer to that, easier penetration)
Would you use sulfas for mastitis?Limited use for mastitis
**Products of what metabolism of sulfas cause damage to what organ? How?Acetylation products ↓ solubility so crystals form, which causes kidney dmg
What ↑ the solubility of sulfas? (Metabolism)Glucuronic acid conjugation products ↑ solubility (but it is usually acetylated which ↓ solubility)
How are sulfas metabolized, & who does this affect most?ACETYLATION, which means dogs kinda struggle w/ it
What are the enteric sulfas I'm gonna care about?Sulfasalazine (colitis in dogs)
Sulfaquinoxaline (coccidiosis in chickens)
Sulfaguanidine (ruminant GI)
Sulfa used for ophthalmic use? Why?Sulfacetamide - bc neutral pH
What is Sulfacetamide used for?Ophthalmic (eyes)
What is Sulfasalazine used for?Enteric, colitis in dogs (salatine crackers for doggie's tummy)
What is Sulfaquinoxaline used for?Coccidiosis in chickens (coccidiosis in cocks gets the nox)
What is Sulfaguanidine used for?Ruminant GI (cow was so hungry it ate an iguana)
What are the topical sulfas?Silver Sulfadiazine, Mafenide
What is Silver Sulfadiazine used for?Topical (silver jewelry on your skin)
What is Mafenide used for?Topical (weird word w/ no 'sulfa' in it, weird topical application)
How do sulfas ↑ their half-life?Sulfas ↓ pH of the urine, which ↓ ionization, which ↑ tubular REABSORPTION, which ↑ THE HALF-LIFE!
What are the immunological toxicities of sulfa drugs? (2)Keratoconjunctivitis Sicca (KCS), Hepatic Necrosis (EYE see your LIVER dipped in SULFur)
**What are the non-immunological toxicities of sulfas? (1, but go into detail) (How do you fix it?)NEPHROTOXICITY! Due to the CRYSTALLURIA! (bc water insoluble, upon dehydration, Sulfonamides precipitate & cause crystal formation) → tubular blockage → hematuria → Hypoprothrombinemia, Aplastic anemia, Thrombocytopenia. Also causes aciduria, (causes ↑ half-life by ↓ ionization which ↑ tubular resorption) so use NaHCO3 aka baking soda to ↑ urine pH to ↓ half-life
How would you ↓ the half-life of sulfas?Sulfa causes aciduria, (causes ↑ half-life by ↓ ionization which ↑ tubular resorption) so use NaHCO3 aka baking soda to ↑ urine pH to ↓ half-life (ionized, can't be reabsorbed)
What are the breed sensitivities of sulfas?Dobermans & ducks
**How do sulfas affect Dobermans?Polyarthritis, fever, cutaneous eruptions, hepatitis
How do sulfas affect ducks & dogs?Hypoglycemia (sulfur roasted duck or dog is low in sugar)
**How do potentiated sulfas affect dogs?Iatrogenic hypothyroidism (slow metabolism = sulfur farts)
Which sulfa is good for resp & enteric infections in calves & swine?Sulfachlorpyridazine (eat this CHLORPY & then breathe easy)
Which sulfa is good for UTIs in small animals, & why?Sulfamethoxazole, bc it is very soluble & rapidly excreted (w/ a UTI you pee like an ox on meth!)
What kind of tissue situation/dz process reduces the effectiveness of sulfas?Pus/purulent tissue (you know what's worse than a wound w/ pus? a wound w/ sulfur-smelling pus. no bueno)
What will delay the absorption of oral sulfas?Food in the belly
How are sulfas excreted?Mostly kidney, but also tears, saliva, bile, milk & sweat (& feces if enteric sulfa)
How do bact develop resistance to sulfas? (4)(1) Chromosome mediated (slow to develop)
(2) Plasmid mediated - rapid, & involve impaired drug penetration
(3) Increased production of PABA
(4) Sulfonamide resistant Dihydropteroate Synthase (DHPS) enzyme


Question Answer
*Cidal or static?Static (mac DIpped lin in the pool w/ chorline & made 4 times more sulfur, I want to STOP going there)
What is the killing kinetics? (Type__), which is?Type 2, Time-Dependent (still folic acid like sulfas, & still same killing kinetic)
Describe their distribution. Why is it this way? Areas it can be in?Wide distribution bc LIPOPHILIC - BBB, prostatic fluid, milk
What is the mechanism by which diamino's work?Reversibly binds & inhibits Dihydrofolate Reductase (DHFR) enzyme (Dihydrofolic acid then cant be converted to folic acid) (folate in the enzyme word means it's closer to the end product)
What are the 3 diaminos we should know?Pyrimethamine
**What is Pyrimethamine used for?Protozoan (p for both of them, also a dose of METH would kill anything)
What is Trimethoprim used for?Usually to make a potentiated sulfa
**What is Ormetoprim used for?Ruminants ( O.R. ORIGINAL RUMINANT gangsta will make you DIA)
Diaminos affect Dihydrofolate Reductase (DHFR) enzyme, mammals have this, are we worried?Not really, it has low affinity for the mammal DHFR so it isnt affected at regular does levels
Metabolism of diaminos? Excretion?Metabolism - Liver (oxidation & conjugation)
Excretion - Urine

Potentiated Sulfas

Question Answer
**Cidal or static? Why is this special?CIDAL - unusual bc usually static+static = additive.
How is the distribution of pot. sulfas? Notable things?Well distributed (SUCH HIGH POTENTIAL!). Penetrates CSF through inflamed meninges, crosses placenta & into milk too
Which bacteria are susceptible to potentiated sulfas?Gram (+): Strep, Staph, Nocardia
Gram (-): Enterobacteriaceae (NOT Pseudomonas) & PROTOZOA (Pneumocystis, Coccidia, Toxoplasma)
Which sulfas are combined w/ Trimethoprim? (3)(1) Sulfadiazine + Trimethoprim
(2) Sulfadoxine + Trimethoprim
(3) Sulfamethoxazole + Trimethoprim (prep 1:5, plasma 1:20)
(doxies die on meth, if you TRIed to give them some)
**Sulfa+trimethoprim combos have what formulation, & what is notable about this?1:5 formulation....however, in plasma, it reaches a 1:20 conc!
Which sulfa is combined w/ Ormetoprim?Sulfadimethoxine + Ormetoprim ( Original Ruminant gangsta met di Ox)
Which sulfa is combined w/ Pyrimethamine?Sulfaquinoxaline + Pyrimethamine (chickens love py as long as there arent protozoa) (both of these alone are used to fight protozoa, it only makes sense that they would go together)
Which admin is well absorbed, & which is slow absorbed?Well - oral
Slow - SC
(potential so good I want to eat it)
How are these metabolized?Liver
Sulfa component (acetylation & conjugation w/ glucuronic acid)
Diamino component (oxide & hydroxylated metabolites)
Excretion of potentiated sulfas?Urine