Test 4: 49 Rx Flashcards
how do calcium channel blockers cause toxicity
Prevents Ca influx into cell, which prevents contraction.
Effects:
– Hypotension
– Bradycardia, reflex tachycardia
– Pulmonary edema
– Hyperglycemia
verapamil, diltiazem, amlodipine
can be sustained release med
how to treat calcium channel blocker toxicity
Calcium gluconate
Vasopressors
Insulin/dextrose - normally the myocardium is fatty acid dependent for energy – however, calcium channel blocker toxicity makes the myocardial cells carbohydrate dependent but at the same time unable to utilize carbohydrates due to the lack of insulin.
what are some common decongestants
Pseudoephedrine (PSE)
Phenylephrine (oral)
stimulate ⍺1 receptors
signs of decongestant overdose
Pseudoephedrine (PSE)
- stimulates both alpha and beta receptors
- B stimulation results in tachycardia, tachyarrhythmias.
- Alpha: peripheral vasoconstriction, hypertension
- Inhibits bladder emptying (stimulates receptors that tighten the bladder sphincter). PSE been used for canine urinary incontinence.
Phenylephrine (oral)
- hyperactivity, vomiting, mydriasis, hyperthermia, disorientation, tachycardia (and sometimes reflex bradycardia)
species specific for decongestants
dogs very senstive
PSE-toxicosis can lead to agitation if mixed with diazepam
narrow therapeutic dose: 1.5 mg/kg 2-3x daily for urinary incontinence in dogs, clinical signs 5-6 mg/kg, death 10-12 mg/kg
treatment for decongestant toxicity
decontamination and symptomatic supportive care (to manage sx such as tachycardia, bradycardia, excess CNS stimulation).
- Acepromazine, chlorpromazine or phenobarbital may be preferable to a benzodiazepine to control tremors, seizures and nervousness.
do not use diazepam in dogs can cause agitation
what are some common antihistamines
Chlorpheniramine
Diphenhydramine (po and dermal) Benadryl® 2% cream (2 gm/100gm = 100 mg/5gm tsp)
Meclizine
clinical signs of antihistamine toxicity
CNS depression, dry mucous membranes, ataxia
– Anticholinergic effects (but not meclizine – in piperazine class)
treatment of antihistamine toxicity
decontamination and
symptomatic supportive care
risk factors for renal toxicity from NSAIDs
pre-existing renal disease
hypovolemia (vomiting, dehydration)
hypotension
why can NSAIDs cause renal damage
can cause decreases renal blood flow
clinical signs of NSAID toxicity
GI: vomiting, diarrhea, anorexia, hematemesis, melena
hepatic: lethargy, weight loss, liver enzyme elevation
renal failure
Narrow margin of safety in both dogs and cats.
NSAIDs can cause decreased renal blood flow, decreased gastric mucous production and decreased platelet aggregation
Cats 2x as sensitive as dogs to NSAIDs due to limited — ability
glucuronyl-conjugating
no advil, tylenol(acetaminophen) or bayer
treatment for NSAID toxicity
Decontamination and symptomatic supportive care.
- GI protectants (avoid bismuth subsalicylate) - Antiulcer meds that have been used: sucralfate, misoprostol, H 2 antagonists
- Fluids
NSAIDs can cause decreased renal blood flow, decreased gastric mucous production and decreased platelet aggregation
clinical signs of acetaminophen toxicity
can be asymptomatic
vomiting, anorexia, methemoglobinemia, edema
species specific acetaminophen toxicties
Dogs are more prone to hepatic necrosis than cats.
Acetaminophen is the most common drug-related cause of Heinz body formation in cats.- methemoglobinuria- liver damage
treatment for acetaminophen toxicity
N-acetylcysteine (NAC) - need to give within 8 hrs
Symptomatic treatment (cats with methemoglobinemia may require methylene blue)
- Although methylene blue is an oxidizing agent, it can be given to cats but at careful low doses.
- Cimetidine and ascorbic acid(Vit C) are not accepted antidotes for acetaminophen poisoning.
Cimetidine and ascorbic acid are not accepted antidotes for —poisoning.
acetaminophen
should use NAC within 8 hrs of ingestion
can treat methemoglobinemia in cats with methylene blue
what in bengay can cause toxicity
aspirin (methyl salicylate)
1 tablespoon= 6.3 grams of aspirin!!
what is toxic in pepto bismol
bismuth subsalicylate (aspirin)
1 tablespoon= 130 mg of aspirin!
clinical signs of aspirin toxicity
vomiting, hyperventilation, fever, hypo or hyperglycemia, metabolic acidosis
if pt becomes acidotic ASA can move into the brain and cause seizures
ASA in petobismol and bengay
— are more susceptible to ASA poisoning than — due to saturation of elimination pathways
Cats
dogs
range of toxicity for ASA
Dogs
- Therapeutic dose: 10-20 mg/kg q 48 hrs).
- Gastric ulcers with 100mg/kg/day for 1-2 weeks
Cats
- As little as 25 mg/kg can cause acute toxicity
treatment for aspirin toxicity
Decontamination and symptomatic supportive care
Sodium bicarbonate increases urinary elimination of aspirin and decreases brain concentrations of aspirin. (try to alkanize pt)
what are some common ⍺2 agonists
clonidine
visine
imidazole decongestant
symptoms of imidazole decongestant toxicity
- CNS depression
- Apnea (not breathing)
- Bradycardia
- Hypotension due to central alpha 2 stimulation. But hypertension if peripheral alpha-2 stimulation.
- Miosis (pupil constricted)
⍺2 agonist: clonidine, visine
treatment for imidazoline decongestants
decontamination and symptomatic
supportive care
- Naloxone may be of benefit for ingestions of imidazolines (has been reported to sometimes reverse coma and hypotension in humans)
⍺2 agonist: clonidine, visine
clinical signs of antacids toxicity
aluminum hydroxide, magnesium
hydroxide, calcium carbonate
minimally toxic
Only symptomatic treatment of the GI effects is needed.
clinical signs of fleet enema (sodium phosphate) toxicity
hyperphosphatemia, hypernatremia, dehydration and shock.
concern is fluid and electrolyte losses.
what causes toxicity in Kaopectate
now contains bismuth subsalicylate (aspirin)
pepto bismol also has bismuth subsalicylate
Kaopectate is an antidiarrheal
side effects of imodium (loperamide) toxicity
can have opioid-like effects (structurally similar to both haloperidol and diphenoxylate).
antidiarrheal med
treatment for imodium toxicity
Naloxone may be effective
Therapeutic dose in dogs is very small (0.08 - 0.1 mg/kg po q 12 hrs) versus the 2mg capsule available for humans.
lomotil toxicity symptoms
opioid that contains anticholinergic (try to stop abuse)
antidiarrheal med
treatment for antidiarrheal med toxicity
decontamination and symptomatic supportive care.
- Naloxone – for diphenoxylate (Lomotil®) and loperamide (Imodium®)
topical zinc oxide toxicity
not toxic unless chronic or very large amount without emesis
found in diaper rash ointment, sunscreen, calamine lotion, astringents.
treatment: supportive care (watch and wait)
clinical signs of calcipotriene toxicity
Synthetic vit D3 Dovonex® (calcipotriene): human psoriasis treatment
– Ingestion: Severe hypercalcemia, renal failure, soft tissue mineralization (in dogs)
– Topical use: only 5-6% is absorbed dermally
vomiting, CNS depression, anorexia, diarrhea, polyuria
Special note: weeks of treatment may be required. Death can occur weeks after an apparent recovery secondary to calcification of cardiac tissue.
treatment for calcipotriene toxicity
- Decontamination
- Supportive care (renal failure).
- Treat elevated serum calcium and phosphorus
- Bisphosphonates (Aredia® - pamidronate is used in humans to treat malignancy-related hypercalcemia)
Special note: weeks of treatment may be required. Death can occur weeks after an apparent recovery secondary to calcification of cardiac tissue.
clinical signs of 5-fluorouracil toxicity
very toxic- 1/2 a tube deadly
Ingestion :
- severe, intractable seizures,
- vomiting and GI mucosal sloughing.
- delayed severe leukopenia (WBC less than 1 x 103)
Topical:
- toxicity has also occurred following dermal application to dogs and cats
Prognosis is poor since a large % of dogs die from intractable seizures
treatment for 5-fluorouracil toxicity
- Seizures rarely respond to diazepam; (success reported in dogs: barbiturates, isoflurane, propofol)
- Filgrastim (for severe leukopenia)
Weeks of monitoring may be required (delayed leukopenia).
list of meds dangerous in small amounts for dogs
Dogs
NSAIDS
Pseudoephedrine
Caffeine
Albuterol
Both species
5-fluorouracil
Calcipotriene
Isoniazid
list of meds that are toxic in small amounts for cats
Both species
5-fluorouracil
Calcipotriene
Isoniazid
Cats
Acetaminophen
Benzocaine
NSAIDS
ASA
In general, oxidant drugs
that induce Heinz body formation (examples: phenols, propofol, phenazopyridine, methylene blue)
