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
Catapres Overdose, Contraindications and Information - Clonidine
Catapres Overdose, Contraindications and Information - Clonidine
OVERDOSE
Tablet
The signs and symptoms of clonidine hydrochloride
overdosage include hypotension, bradycardia,
lethargy, irritability, weakness, somnolence, diminished or absent
reflexes, miosis, vomiting
and hypoventilation. With large overdoses, reversible
cardiac conduction
defects or arrhythmias, apnea, seizures and transient
hypertension have
been reported. The oral LD50of clonidine in rats was
465 mg/kg, and in mice 206 mg/kg.
The general treatment
of clonidine hydrochloride
overdosage may include intravenous fluids as indicated. Bradycardia
can be treated with intravenous fluids as indicated. Bradycardia
can be treated with intravenous
atropine sulfate and hypotension
with dopamine infusion
in addition to intravenous
fluids. Hypertension, associated with overdosage, has been treated
with intravenous furosemide
or diazoxide or alpha-blocking
agents such as phentolamine.
Tolazoline, an alpha-blocker, in intravenous
doses of 10 mg at 30-minute
intervals, may reverse clonidine's effects if other efforts fail.
Routine hemodialysis is of limited benefit, since a maximum
of 5% of circulating clonidine is removed.
In a patient who ingested
100 mg clonidine hydrochloride,
plasma clonidine levels
were 60 ng/ml (one hour), 190 ng/ml (1.5 hours), 370 ng/ml (two
hours) and 120 ng/ml (5.5 and 6.5 hours). This patient
developed hypertension followed by hypotension,
bradycardia, apnea,
hallucinations, semicoma, and premature
ventricular contractions.
The patient fully recovered
after intensive treatment.
Epidural Injection
Hypertension may develop early and may be followed by hypotension,
bradycardia, respiratory depression,
hypothermia, drowsiness,
decreased or absent reflexes, irritability, and miosis. With large
oral overdoses, reversible
cardiac conduction defects or arrhythmias, apnea,
coma, and seizures have
been reported. As little
as 100 mcg of oral
clonidine has produced signs of toxicity in pediatric
patients.
There is no specific
antidote for clonidine
overdosage. Supportive care may include atropine sulfate
for bradycardia,
intravenous fluids
and/or vasopressor agents for hypotension. Hypertension associated
with overdosage has been treated with intravenous
furosemide, diazoxide
or alpha-blocking agents such
as phentolamine. Naloxone may be useful adjunct
in the treatment of clonidine-induced respiratory
depression, hypotension,
and/or coma; blood pressure
should be monitored since administration
of naloxone has occasionally resulted in paradoxical hypertension.
Tolazoline administration has yielded inconsistent results and is
not recommended as first-line therapy. Dialysis is not likely to
significantly enhance the elimination
of clonidine.
The largest overdose
reported to date involved a 28-year old white
male who ingested 100 mg
of clonidine HCl powder. This patient
developed hypertension followed by hypotension,
bradycardia, apnea,
hallucinations, semicoma, and premature
ventricular contractions.
The patient fully recovered
after intensive treatment. Plasma clonidine levels were 60 ng/ml
after 1 hour, 190 ng/ml after 1.5 hours, 370 ng/ml after 2 hours,
and 120 ng/ml after 5.5 and 6.5 hours. In
mice and rats, the oral
LD50 of clonidine is 206 and 465 mg/kg, respectively.
CONTRAINDICATIONS
Tablet
None known.
Epidural Injection
Clonidine HCl is contraindicated in patients with a history
of sensitization or allergic
reactions to clonidine. Epidural administration
is contraindicated in the presence of an injection
site infection,
in patients on anticoagulant therapy, and in those with a bleeding
diathesis. Administration of epidural clonidine HCl above the C4
dermatome is contraindicated
since there are no adequate data to support
such use (see WARNINGS.)
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