Drug Facts Flashcards
What do Benzos NOT do
They DO NOT:
- cause skeletal muscle relaxation for surgery (only for back pain and such)
- alter the dose of muscle relaxant required (don’t potentiate muscle relaxants)
- induce hepatic enzymes
- activate the GABA receptor (they increase the afinity of GABA to the GABAa receptor)
- produce isoelectric EEG
- attenuate (blunt) the increase in ICP, HR and BP related to laryngoscopy
Water soluble drugs
Midazolam (Versed) - water soluble in preparation, lipid soluble in the body (due to the imidazole ring closing at physiologic pH)
Etomidate - water soluble in the bottle, lipid soluble in the body (due to the imidazole ring closing at physiologic pH)
Dexmedetomidine (Precedex)
Drugs with active metabolites
Midazolam (Versed) → 1-hydroxymidazolam
Diazepam (Valium) → desmethyldiazepam (long ½ life ≈ 48-96 hrs)
Morphine → Moprhine-6-Glucoronide (more potent) & normorphine
Meperidine → Normeperidine (½ potency, long acting ≈ 3 days → think risk for seizures)
Hydromorphone (Dilaudid) → hydromorphone-3-glucoronide (in renal failure can accumulate = myoclonus and seizure)
Sufentanil → desmethylsufentanil (weak)
Ketamine → Norketamine (only 20-25% activity as parent drug)
thiopental and pregnancy
prolonged elimination 1/2 t due to increased protein binding
causes myoclonus
Etomidate > Methohexital > Propofol > Thiopental
what drugs cannot be mixed with barbiturates
- opioids (alfentanil, sufentanil)
- cathecholamines
- NMB (pancuronium, vecuronium, atracuriun)
- Midazolam
- LR
they are too acidic and will precipitate
when reconstituing from powder use sterile water or normal saline
base or acid?
opioids
barbs
benzos
ketamine
local anesthetics
opioid = weak base
barbs = alkaline in the bottle, acid at physiologic pH
benzos = bases
ketamine = base
propofol = acid
local anesthetics = weak base (stored in acidic solution to make it water soluble in the vial)
