Phenibut 100

INSTRUCTIONS FOR MEDICAL USE OF THE MEDICINAL PRODUCT PHENIBUT 100 (PHENIBUT 100)

Composition:

Active substance: phenibut;

One sachet contains 100 mg of phenibut;

Excipients: mannite (E 421), thaumatin (E 957) (contains maltodextrin), flavoring "Orange, dry" (contains flavoring ingredients, maltodextrin, sodium octenyl succinate starch (E 1450), glucose, ascorbyl palmitate (E 304 (I)), butylated hydroxyanisole (E 320)).

Pharmaceutical form. Oral powder for solution.

Main physicochemical properties: white or almost white powder with a yellowish tint. Yellow specks are permissible.

Pharmacotherapeutic group. Psychostimulants and nootropic agents. Phenibut.

ATC code N06BX22.

Pharmacological Properties

Pharmacodynamics

Phenibut is a derivative of γ-aminobutyric acid and phenylethylamine.

Its main effects are anti-hypoxic and anti-amnesic. The drug improves memory and attention, enhances learning processes, and increases physical and mental performance. Psychological parameters (speed and accuracy of sensorimotor reactions) improve under the influence of the drug. It has been established that the drug improves the energy potential of neurons by enhancing mitochondrial function.

The drug also has tranquilizing properties: it reduces psychoemotional tension, anxiety, fear, emotional lability, and irritability, improves sleep, and prolongs and enhances the effects of hypnotics, narcotic agents, neuroleptics, and anticonvulsants. The drug binds exclusively to GABA-ß receptors in the brain, thus exerting a moderate calming effect without causing undesirable sedative effects such as drowsiness, dizziness, or reduced attention and performance. The drug prolongs the latent period and shortens the duration and intensity of nystagmus, and possesses antiepileptic activity. It does not affect cholinergic or adrenergic receptors.

The drug significantly reduces manifestations of asthenia and vasovegetative symptoms, including headache and a sensation of heaviness in the head. In patients with asthenia and emotionally labile individuals, the drug improves well-being without causing excitation.

Pharmacokinetics

The drug is rapidly absorbed after oral administration and penetrates into all tissues of the body, completely crossing the blood-brain barrier. Distribution in the liver and kidneys is close to uniform, while in the brain and blood it is lower than uniform. A significant amount of the administered drug is detected in urine within 3 hours; at the same time, the concentration of the drug in brain tissue does not decrease, and the drug remains detectable in the brain for up to 6 hours. The next day, the drug can only be detected in urine; it remains detectable in urine for up to 2 days after intake, but the amount detected constitutes only 5% of the administered dose. The highest binding of the drug occurs in the liver (80%), and this binding is non-specific. No accumulation is observed with repeated administration.

Clinical characteristics.

Indications.

Asthenic and anxiety-neurotic states (emotional instability, memory impairment, decreased concentration), restlessness, fear, anxiety, obsessive neurosis.

Stuttering, enuresis, tics.

Ménière's disease in children, vertigo associated with vestibular apparatus dysfunction, prevention of motion sickness.

Prevention of stress conditions prior to surgeries or painful diagnostic procedures.

Contraindications.

Hypersensitivity to the components of the drug. Acute renal failure.

Interaction with other medicinal products and other forms of interaction.

The drug can be used with other medicinal products, including psychotropic agents – tranquilizers and neuroleptics (effects are mutually enhanced).

Special precautions for use.

Caution should be exercised when prescribing the drug to children with gastrointestinal disorders due to the irritant effect of the preparation. Such children should be administered lower doses.

With prolonged use, blood cell counts and liver function test parameters should be monitored regularly.

If a patient has known intolerance to certain sugars, medical advice should be sought before taking this medicinal product.

Use during pregnancy or breastfeeding.

The use of this drug is not recommended during pregnancy or breastfeeding due to insufficient data on its safety during these periods.

Ability to influence reaction rate when driving or operating machinery.

Patients who experience drowsiness, dizziness, or other central nervous system disturbances during treatment with this drug should refrain from driving or operating machinery.

Method of Administration and Dosage

Dissolve the contents of the sachet in 0.5 glass of boiled water and take orally before meals.

The treatment course lasts 2–6 weeks.

Children:
From 3–4 years of age: 100 mg (1 sachet) twice daily;
5–6 years of age: 100 mg three times daily;
7–10 years of age: 200 mg (2 sachets of 100 mg each) twice daily;
11–14 years of age: 200 mg (2 sachets of 100 mg each) three times daily.

Maximum single doses for children: under 6 years – 100 mg; 7–10 years – 200 mg; 11–14 years – 300 mg.

For prevention of motion sickness, take a single dose of the drug one hour before traveling by sea, land, or air.

The drug may be combined with other psychotropic agents; in such cases, the dosage of this drug and of other concomitantly administered drugs may be reduced.

If one or several doses have been missed, continue treatment according to the previously prescribed dosage regimen.

Children

Experience with use of the drug in children under 3 years of age has not been studied.

Overdose

The drug is low in toxicity. However, at daily doses of 7–14 g during prolonged use, it may become hepatotoxic.

These doses are significantly higher than the recommended average therapeutic doses according to the child's age. Eosinophilia and fatty liver degeneration were observed only at higher administered doses. Such changes were not noted when lower doses were used.

Symptoms: drowsiness, nausea, vomiting, possible development of arterial hypotension, acute renal failure.

Treatment: gastric lavage. Symptomatic therapy.

In case of complications (arterial hypotension, renal failure), supportive and symptomatic measures should be applied.

Adverse reactions.

Central nervous system side effects: drowsiness (at the beginning of treatment), headache and dizziness (at doses exceeding 2 g per day; the intensity of these adverse effects decreases when the dose is reduced).

Gastrointestinal side effects: nausea (at the beginning of treatment), vomiting, diarrhea, epigastric pain.

Hepatobiliary side effects: hepatotoxicity (with prolonged use of high doses).

Immune system side effects: allergic reactions, including rash, pruritus, urticaria, skin redness.

Psychiatric disorders: emotional lability, sleep disturbances (these adverse reactions may occur in children when the medicinal product is used contrary to the instructions for use).

If any adverse reactions not listed in this instruction occur during treatment, or if any of the listed adverse reactions are particularly severe, medical advice should be sought.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after medicinal product authorization is important. It allows ongoing monitoring of the benefit-risk balance of the medicinal product. Medical and pharmaceutical professionals, as well as patients or their legal representatives, should report all suspected adverse reactions and lack of efficacy via the Automated Information System for Pharmacovigilance at the following link: https://aisf.dec.gov.ua.

Shelf life. 2 years.

Storage conditions.

Store in the original packaging at a temperature not exceeding 25 °C.

Keep out of reach of children.

Packaging. 1 g in a sachet, 10 sachets (1×10) per box.

Prescription status. Prescription only.

Manufacturer. LIMITED LIABILITY COMPANY "CORPORATION "ZDOROV'YA".

Manufacturer's address and location of business activity. 22, Shevchenka Street, Kharkiv, Kharkiv Oblast, 61013, Ukraine.