General Methods of Tx Flashcards
What methods are used for prevention of absorption?
- gastric emptying
- emesis
- -gastric lavage
- adsorption
- activated charcoal
- catharsis
- affects the GI transit time
- dilution
What is used to stimulate emesis?
- syrup of ipecac
What are some of the contraindications of using syrup of ipecac?
- corrosive/caustic agents
- petroleum distillate
What are some of the complications associated with gastric lavage?
- cardiac arrythmias
- low pO2
- laryngospasm
- pharingeal injury
- esophageal or gastric perforation
In what location is activated charcoal most useful in binding poisons?
- small intestine (one they have left the stomach)
What agents are activated charcoal NOT useful for?
- corrosive ingestions (ACIDS)
- methanol/ethanol
- CN, As
- Fe
- F
- heavy metals
- lithium
- potassium
- petroleum distillates
- tobramycin
What are the contraindications behind using activated charcoal?
- ingestion of caustic substances
- presence of ileum or bowel obstruction
What are the complications associated with using activated charcoal?
- vomiting
- aspiration pneumonitis
- constipation
- GI obstruction
- charcoal empyema
What is the dose of activated charcoal?
- 30-100 g as a slurry in water (there are also sorbitol containing compounds)
What is the effect of MDAC?
- may help prevent reabsorption of the drug in the GIT
- increases the clearance of drugs excreted in the feces
- known as GI dialysis
- ensures that there is a marked serum to GI lumen concentration gradient
- route of admin other than oral
What does MDAC have efficacy in?
- analgesics
- antiarrythmics
- anticonvulsants
- benzos
- beta blockers
- cardiac glycs.
- TCAs
- NSAIDs
- salicylates
- sedatives
- – A LOT
What is an indication for a whole bowel irrigation?
- ingestion of iron or zinc salts
- ingestion of SR medications
- ingestion of drug packets
- ingestion of crack vials
What are some of the CIs to whole bowel irrigations?
- presence of ileum or GI obstruction
- GI bleeding or perforation
What are some of the complications of whole bowel irrigations?
- abdominal cramping
- vomiting
- profuse diarrhea
- hyperchloremia (essential to monitor electrolytes)
What is the technique of whole bowel irrigations?
- administer large volumes of isotonic, non absorbable polyethylene glycol/electrolyte solution over 40 minutes to several hours
(example of this is colyte)
What is the pro of using a cathartic in bowel irrigation?
- less violent
- used to move the poison or the poison/charcoal complex through the GIT
- can help to remove the poison
- can help decrease absorption
- can help prevent the formation of concentrations of drug or drug/charcoal complex
- same CI and complications as with whole-bowel irrigation
What are some of the examples of a cathartic?
- sorbitol
- magnesium citrate
- magnesium or sodium sulfate
In what situation might dilution have some value?
- after the ingestion of a corrosive agent
- CI in coma and convulsions
(NEVER USE WITH ACID)
What are the indications that would lead you to think that enhancement of elimination would be a good way to go to remove the toxin?
- failure to respond to supportive care (hypotension, heart failure, seizures, metabolic acidosis, or dysrhythmia)
- normal route of elimination is impaired
- plasma concentration indicates high risk of mortality
- concomitant disease and are in a high or low age group
What method does diuresis work on?
- increasing the renal clearance by manipulation of the pH
What is alkaline diuresis?
- give NaHCO3 to increase urinary pH to 7-8 (increases renal excretion of salicylate, isoniazid and phenobarb)
What is acid diuresis?
- give NH4Cl to reduce the urinary pH to 4.5-5.5 (works for weak bases such as amphetamines and phencyclidine)
What drugs does peritoneal dialysis remove?
water soluble, LMW (< 500 Da), poorly protein bound compounds that have a low Vd
(alcohol, lithium, salicylates and theophylline)
What are examples of drugs that GI dialysis can remove?
- phenobarbital
- theophylline
- VPA
What are the indications for hemodialysis?
- poison is dialysable
- patient is deteriorating despite care
- severe electrolyte problems
- lethal blood levels
- risk of prolonged coma
- risk of renal failure
What specific poisonings is hemodialysis useful for?
- methanol
- ethylene glycol
- salicylate
- theophylline
- ethanol
What are some of the complications of hemodialysis?
- clotting and leaking of blood from around connections
- embolus
- hypotension
- convulsions
- arrhythmias
- infections
What is charcoal hemoperfusion?
- compounds have to be able to be absorbed by AC
- cartridge containing a sorbent with large SA
- cartridge changes as often as q2-4h
- anticoagulation
- usually performed for 4-6 hours
- hemoperfusion is not limited by plasma protein binding
What are some examples of drugs that can be removed by hemoperfusion?
- carbamazepine, phenobarbital, phenytoin and theophylline
What is hemo filtration?
- movement of plasma across a semi-permeable membrane in response to hydrostatic pressure gradient
- no dialysate solution on the other side of the membrane
- smaller solutes are transported across the membrane following the water (bulk flow) while larger solutes are excluded
What is plasmapheresis and exchange transfusion?
- used to eliminate molecules with large MW ( > 15,000 Da)
- both remove plasma proteins (benefit of removing protein bound molecules, dig-dig antibodies and thyroxine)
- risk of infections and allergic reactions
- expensive
- exchange transfusion appropriate in small infants
What is a lipids rescue?
- IV lipid emulsions
- lipid sink of pharmacokinetic sequestrations of (local anesthetics, TCA or CCBs)
