Drugs, toxins Flashcards
A cat presents for acute ataxia and vocalizing. On physical exam, it is hypothermic and has elevated TELs. What toxicity do you suspect?
Marijuana
JVIM 2021, Kulpa
What effect does robenacoxib have on creatinine in healthy and CKD (IRIS 2-3) cats treated for 4-12 weeks?
Mild but probably clinically irrelevant increase
JVIM 2021, King
An aggressive German shepherd is sedated for an abdominal ultrasound to investigate acute vomiting (concern for FB). AUS shows GB thickening and “double rim sign”.
–What is the likely cause?
–When could you recheck to bolster your suspicion?
–Sedation with dexdomitor
–GB thickening should resolve in 12-24hrs
JVIM 2021, Seitz
Which is a better protocol for plane and duration of sedation while minimizing cardiovascular depression?
hydromorphone/alfaxalone vs hydro/alfax/midaz
Hydro/alfax/midaz – since benzos have minimal CV effects, adding midaz is better than increasing dose of alfax
JVIM 2021, Wheeler
What is the MoA of mycophenolate?
Myco –> mycophenolic acid –> selective and reversible inhbition of inosine-5’monophosphate dehydrogenase (IMPDH) –> can’t make guanine –> lymphocytes can’t proliferate
JVIM 2021, Fukushima
Regarding GI adverse effects in dogs treated with mycophenolate:
–Frequency?
–Median time to onset?
–At least 2 possible MoAs?
–Not dose dependent – possible explanation?
–24%
–10d after starting myco
–MoAs:
1) Metabolite acyl-glucoronide (acyl-MPAC) is cytotoxic
2) Hydrolysis metabolite N-(2-hydroxyethyl) morpholine is irritating (rabbit model)
3) Dysbiosis (rat model)
–Widely variable pharmacokinetics from dog to dog
JVIM 2021, Fukushima
For mycophenolate, what are two possible adverse effects (other than GI) and their frequency? Do they resolve with discontinuation?
–Neutropenia 4% – may be persistent despite d/c’ing myco
–Dermal eruptions 1.5% – resolve with d/c
JVIM 2021, Fukushima
PU/PD is a common side effect of pred. How does desmopressin affect the behavior, USG, and Na? What does this imply about the mechanism of PU/PD?
Desmopressin –> decr PU/PD, incr USG, decr Na
Means PU/PD from pred is (at least partially) due to ADH antagonism (release vs receptor)
JVIM 2021, Galati
Describe at least 3 mechanisms by which vincristine helps in the treatment of ITP. What is the median time to Plt >40K?
–Incr megakaryocyte fragmentation
–Inhibits plt phagocytosis
–Inhibit formation and function of anti-Plt Ab
–Median 3-5d to plt >40K
JVIM 2021, LaQuaglia
JVIM 2021, Allen
Regarding neutropenia associated with vinc 0.02mg/kg (tx for ITP):
–Frequency?
–Degree?
–One risk factor and possible mechanism? How to avoid this?
–Effect on outcome?
–15% (large ITP study) to 50% (healthy research dogs)
–Most were NOT severe
–Cyclosporine –> neutropenia was more likely and more severe. Inhibition of CYP450 –> decr vinc clearance. Takes 5d to clear vinc – start cyclosporine after that.
–No effect on survival but did have longer hospital stay
JVIM 2021, LaQuaglia
JVIM 2021, Allen
How do serum gastrin levels correlate with likelihood and severity of GI ulceration with meloxicam use?
Incr gastrin –> more likely to have an ulcer. Higher = more severe.
JVIM 2021, Elfadadny
What is the purpose of enteric coating on omeprazole?
Degrades at a certain pH –> lets the drug survive the stomach and released in duodenum
JVIM 2021, Gaier
The goal for PPI tx is for gastric pH to be ____ for ____% of the day. BID omeprazole achieves this for ___% of the day, by day ____ of tx.
Gastric pH >/=3 for 75% of the day
Omeprazole BID –> pH >/=3 for 90% of the day by day 2 of tx
JVIM 2021, Gaier
For dogs with creat >4.0, how frequently should you dose ampicillin 22mg/kg IV to maintain an appropriately high MIC?
SID is sufficient (but small study and relationship between GFR and creat is not linear – so interpret with caution)
JVIM 2021, Monoghan
What is diuretic braking and why does this happen?
Furosemide CRI –> decr urine production after a few hours due to RAAS activation
JVIM 2021, Adin
What is the effect of ACEi and spironolactone on diuretic braking?
No effect – probably escape mechanisms to make AT II
JVIM 2021, Adin
What are at least 3 possible mechanisms of systemic hypertension secondary to renal disease?
–Impaired Na handling
–Excessive RAAS activation
–Hyperactive sympathetic NS
–Endothelial factors
JVIM 2021, Fowler
Which was most effective for lowering BP and UPC in PLN dogs and two possible explanations:
–ACEi alone
–Telmisartan alone
–ACEi+Telmisartan
ACEi+telmisartan
Possibly because 1) case selection bias (more severely affected dogs in Tel only group) vs 2) ACEi+Tel truly more effective
Lots of limitations in this retrospective study – interpret with caution
JVIM 2021, Fowler
How often do ACEi or ARBs need to be discontinued due to hyperkalemia?
Infrequent – most hyperkalemia is modest
JVIM 2021, Fowler
What are the basic mechanisms that maximize duration of action for the following:
–Traditional long acting insulin (such as glargine)
–AKS-267c (once weekly insulin)
–Traditional long acting insulins manipulate the SQ depot (to cause slow absorption) and receptor affinity (since once it’s absorbed by the cell, it’s degraded)
–AKS-267c: insulin + Fc –> binds host Fc neonatal receptor (FcRn – ubiquitous, found on most/all cell types) –> endocytosis –> intracellularly recycled
JVIM 2021, Gilor
How do glargine vs AKS-267c (weekly insulin) compare in terms of clinical DM control, glycemic variability, and hypoglycemic events?
AKS-267c had decr glycemic variability, similar clinical control, no hypoglycemic events
JVIM 2021, Gilor
What are the gastric pH goals (pH and proportion of the day) for the following situations (adopted from human med):
–Duodenal ulceration
–Esophagitis
–Optimal clot formation (ex: if severe GI bleed)
In healthy dogs, how do IV esomeprazole, IV pantoprazole, and famotidine CRI compare with respect to the goals above? Which maintained the highest pH the longest?
–Duodenal ulceration >/= 3 for 75% of the day
–Esophagitis >/= 4 for 2/3 of the day
–Optimal clot formation (ex: if severe GI bleed): >6
Esomeprazole and famotidine performed similarly and reached these goals. Pantoprazole 1mg/kg BID did not reach these goals. Esomeprazole had the highest duration of pH >5 and >6.
JVIM 2020, Kuhl