A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Nembutal Overdose, Contraindications and Information - Pentobarbital
Nembutal Overdose, Contraindications and Information - Pentobarbital
OVERDOSE
The toxic dose
of barbiturates
varies considerably. In general,
an oral dose of 1 gram
of most barbiturates
produces serious poisoning
in an adult. Death commonly occurs after 2 to 10 grams of ingested
barbiturate. Barbiturate intoxication may be confused with alcoholism,
bromide intoxication,
and with various neurological disorders.
Acute overdosage with barbiturates
is manifested by CNS and
respiratory depression which may progress
to Cheyne-Stokes respiration,
areflexia, constriction of the pupils to a slight degree
(though in severe poisoning they may show
paralytic dilation),
oliguria, tachycardia,
hypotension, lowered body
temperature, and coma. Typical shock
syndrome (apnea, circulatory
collapse, respiratory
arrest, and death) may occur.
In extreme overdose, all electrical activity
in the brain may cease,
in which case a “flat”
EEG normally equated with
clinical death
cannot be accepted. This effect
is fully reversible
unless hypoxic damage occurs. Consideration should be given to the
possibility of barbiturate intoxication even in situations that
appear to involve trauma.
Complications such as
pneumonia, pulmonary
edema, cardiac
arrhythmias, congestive heart
failure, and renal failure
may occur. Uremia may increase CNS sensitivity
to barbiturates. Differential diagnosis
should include hypoglycemia, head
trauma, cerebrovascular
accidents, convulsive
states, and diabetic
coma. Blood levels from acute
overdosage for some barbiturates are listed in Table 2.
Table 2.—Concentration ofBarbiturate in the Blood Versus
Degree of CNS Depression
|
Blood barbiturate level in ppm
(µg/ml)
|
|
|
Degree of depression in nontolerant persons*
|
|
Barbiturate
|
Onset/
Duration
|
1
|
2
|
3
|
4
|
5
|
|
Pentobarbital
|
Fast/short
|
2
|
0.5to3
|
10to15
|
12to25
|
15to40
|
|
Secobarbital
|
Fast/short
|
2
|
0.5to5
|
10to15
|
15to25
|
15to40
|
|
Amobarbital
|
Intermediate/ intermediate
|
3
|
2to10
|
30to40
|
30to60
|
40to80
|
|
Butabarbital
|
Intermediate/ intermediate
|
5
|
3to25
|
40to60
|
50to80
|
60to100
|
|
Phenobarbital
|
Slow/long
|
10
|
5to40
|
50to80
|
70to120
|
100to200
|
- Under the influence and appreciably impaired for
purposes of driving a motor
vehicle or performing
tasks requiring alertness and unimpaired judgment
and reaction time.
- Sedated, therapeutic
range, calm, relaxed, and easily aroused.
- Comatose, difficult to arouse, significant
depression of respiration.
- Compatible with death
in aged or ill
persons or in presence of obstructed airway,
other toxic agents,
or exposure to cold.
- Usual lethal
level, the upper end of
the range includes those
who received some supportive treatment.
Treatment of overdosage is mainly supportive and consists of the
following:
- Maintenance of an adequate airway,
with assisted respiration
and oxygen administration as necessary.
- Monitoring of vital
signs and fluid balance.
- If the patient is
conscious and has
not lost the gag reflex,
emesis may be induced
with ipecac. Care should be taken to prevent pulmonary
aspiration of vomitus. After completion of vomiting,
30 grams activated charcoal
in a glass of water
may be administered.
- If emesis is contraindicated,
gastric lavage
may be performed with a cuffed endotracheal t.b.
in place with the patient
in the face down
position. Activated charcoal
may be left in the emptied
stomach and a saline
cathartic administered.
- Fluid therapy and
other standard treatment
for shock, if needed.
- If renal function
is normal, forced diuresis
may aid in the elimination
of the barbiturate. Alkalinization of the urine
increases renal excretion
of some barbiturates, especially phenobarbital, also aprobarbital,
and mephobarbital (which is metabolized to phenobarbital).
- Although not recommended as a routine procedure, hemodialysis
may be used in severe barbiturate intoxications or if the patient
is anuric or in shock.
- Patient should be rolled from side
to side every 30 minutes.
- Antibiotics should be given if pneumonia
is suspected.
- Appropriate nursing
care to prevent hypostatic
pneumonia, decubiti,
aspiration, and other complications of patients with altered states
of consciousness.
CONTRAINDICATIONS
Barbiturates are contraindicated in patients with known barbiturate
sensitivity. Barbiturates are also contraindicated in patients with
a history of manifest
or latent porphyria.
top
