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International generic name
Phenobarbital
Drug form and composition
Solution for injection. One ampoule of 2 ml (10%) contains 200 mg Sodium Phenobarbital
(100 mg/ml).
Indications
The injection solution is used as an anticonvulsive agent in the treatment of
following conditions: epilepsy, epileptic status, convulsions, due to hyperpyrexia
or overdosing of medicines, stimulating the CNS. The preparation is used as a premedication
and after surgery, in combination with analgesics. In prevention of neonatal bilirubin
encephalopathy.
Dosage and administration
As an anticonvulsive medicine in adults the preparation is used intravenously
in dose 100-320 mg, till maximal dose of 600 mg /24 hours. In children it is applied
intravenously in dose 10-20 mg per kg body weight. The maintaining daily dose is
1-6 mg per kg body weight. Preoperatively in adults is applied intramuscularly in
dose 130-200 mg, 6-9 minutes before the surgery. In the treatment of hyperbilirubinemia
in newborns is applied intramuscularly, in dose 5-10 mg per kg body weight in the
first several days after the birth.
Contraindications
Hypersensitivity to barbiturates; porphyria; severe liver disorders; renal failure;
respiratory tract diseases, accompanied with dyspnea and obstruction; pregnancy
and lactation.
Special warnings and precautions
In elderly and debil patients, as well as in children a higher sensitivity to
barbiturates is seen, which is expressed by different reaction, including excitation,
confusion or depression. It requires in such patients the dose to be carefully specified
and reduced. In long-term treatment dependence to the drug is possible to appear
(mental and physical). In abrupt discontinuation of the treatment a severe abstinence
could be seen. Aforementioned requires the preparation to be applied for a short
time, and to be stopped gradually. Phenobarbital exerts powerful influence on the
active attention, reflex activity to external stimuli. It retards reactions of the
patient, for this reason the preparation should not be used in drivers and machinery
operating persons.
Drug interactions
Phenobarbital is an inductor of the liver microsomal drugs, including metabolizing
enzymes. It diminishes the action of the oral anticoagulants; griseofulvin; gestagens
and estrogen; glucocorticoids; increases the toxicity of the metotrexat; potentiates
effects of the antihypertensive drugs.
Adverse reactions
Risk of addiction; abstinence syndrome (after abrupt discontinuation of long-term
treatment); prominent sedation in patients with epilepsy; spirits changes; memory
and cognitive function disorders; exantema; photosensibility.
Pharmacological mechanisms
Phenobarbital is a barbiturate derivative possessing a nonselective depressive
effect on the CNS. It facilitates the inhibitor action of the GAFA in several regions
of CNS. Together with potentiating of the GAFA mediation Phenobarbital depresses
unselectively the action of the stimulating neuromediators and influences the neuron
membrane function out of synapse zone. As an anticonvulsive preparation Phenobarbital
depresses selectively abnormally excited neurons in epileptic status, prolonged
the posttetanic potentiation and improving the presynaptic inhibition. Phenobarbital
possesses following additional pharmacology effects: analgesic; spasmolytic (on
the smooth muscles) and moderate hypotensive effect.
Supplied
10 or 100 ampoules of 2 ml (200 mg).
Expiry
2 years.
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