Barbiturates Flashcards
1
Q
Mechanism of action
A
- interact with GABA(A) alpha subunit receptor
- increase duration of Cl- ion channel opening -> hyper polarize postsynaptic cell membrane
- block AMPA (excitatory) receptor- glutamate
2
Q
Pharmacokinetics
A
- NaP 83% bound to albumin
- highly lipid soluble
- hepatic metabolism
- renal elimination
3
Q
Time to unconsciousness
A
CNS uptake in 30 sec
prompt awakening
4
Q
CV effects
A
- decrease SBP, SVR, CO
- rebound increase HR
- d/t myocardial depression & increased venous capacitance
5
Q
Pulmonary effects
A
- resp depression -> APNEA
- decrease TV
6
Q
CNS effects
A
decreased CBF, ICP, CMRO2
7
Q
Renal effects
A
decrease in blood flow, GFR
8
Q
pH effects
A
- metabolic acidosis- increase effects of BARBS
- metabolic alkalosis- decrease effects of BARBS
9
Q
Thiopental (NaP) concentration
A
2.5% solution (25 mg/ml)
10
Q
Methohexital concentration
A
1% solution (10 mg/ml)
11
Q
Induction dose
A
NaP 3-5 mg/kg
Methohexital 1-1.5 mg/kg
PR methohexital 20-30 mg/kg as sedative
12
Q
Risks
A
- extravasation -> tissue sloughing
- don’t mix IV NaP & SUX
- IA injection -> vasocxn
- induce CYP450
- contraindicated with Acute Intermittent Porphyria
- hyperalgesia
- histamine release
13
Q
Acute Intermittent Porphyria
A
-rare autosomal dominant metabolic disorder affecting the production of heme
