Histafen

INSTRUCTION FOR MEDICAL USE OF THE MEDICINAL PRODUCT GISTAPHEN (GISTAPHEN)

Composition:

Active substance: sehofenadine;

One tablet contains 50 mg of sehofenadine hydrochloride, calculated as the anhydrous substance;

Excipients: lactose monohydrate, microcrystalline cellulose, corn starch, colloidal anhydrous silicon dioxide, magnesium stearate.

Pharmaceutical form. Tablets.

Main physicochemical properties: white or almost white, flat cylindrical tablets with a bevel and a score line on one side of the tablet.

Pharmacotherapeutic group. Antihistamines for systemic use. ATC code R06AX32.

Pharmacological properties.

Pharmacodynamics.

Cetirizine is an H1-receptor antagonist and a moderate blocker of 5HT1-serotonin receptors; thus, it reduces the effects of histamine and serotonin, mediators of allergy. A distinctive feature of the drug is that its antihistaminic action is achieved not only by blocking H1-receptors but also by reducing histamine levels in tissues through accelerating its metabolism by the enzyme diamine oxidase, which breaks down endogenous histamine. Cetirizine prevents or reduces the spasmogenic effects of histamine and serotonin on smooth muscles of the bronchi, intestines, and blood vessels, decreases capillary permeability, and exerts a pronounced antipruritic effect. Cetirizine affects the body's immunologic reactivity by reducing the number of antibody-producing and rosette-forming cells in the spleen, bone marrow, and lymph nodes, as well as decreasing elevated concentrations of immunoglobulins of classes A and G.

The drug poorly penetrates the blood-brain barrier, which explains the absence of a pronounced depressant effect on the central nervous system. However, in individual cases with increased individual sensitivity to the drug, a mild sedative effect may occur. Cetirizine does not affect blood and urine biochemical parameters (including blood glucose and cholesterol concentrations), arterial blood pressure, electrocardiogram readings, does not increase the latent period of the conditioned reflex, and does not influence electroencephalogram parameters.

Pharmacokinetics.

The drug is rapidly absorbed in the gastrointestinal tract. Maximum plasma concentration is reached within 1–2 hours. It is metabolized in the liver, forming a pharmacologically inactive metabolite. After a single 50 mg dose, the elimination half-life is 12 hours, while after repeated administration it decreases to 5.8 hours. The use of the drug does not cause accumulation phenomena. More than 20% of the dose is excreted by the kidneys and 50% by the intestine. Approximately 30% of the dose is excreted unchanged, and 40–50% as metabolites.

Clinical characteristics.

Indications.

Acute and chronic allergic diseases in adults: pollinosis, allergic rhinitis, rhinosinopaties (atopic and infectious-allergic); allergic reactions associated with the use of medicinal products, food products, household chemicals.

Allergic and non-allergic diseases accompanied by skin itching (allergic or atopic dermatitis, skin vasculitis, neurodermatitis, lichen planus) in adults. Atopic and infectious-allergic dermatitis in children aged 12 years and older.

Prevention of allergic diseases (prior to seasonal exacerbation) and maintenance therapy in adults.

Contraindications.

Hypersensitivity to sekhifenadine or to excipients of the drug, bronchial asthma attacks.

The use of antihistamines is contraindicated in patients taking monoamine oxidase inhibitors (MAO inhibitors).

Contraindicated during pregnancy and breastfeeding.

Interaction with other medicinal products and other types of interactions.

Histafen may be used in combination with other locally-acting medicinal products (ointments, compresses, eye drops, nasal drops).

Histafen does not enhance the central nervous system depressant effects of sedatives or ethanol-containing drugs.

The use of the drug is contraindicated with concomitant intake of MAO inhibitors.

Special precautions for use

Caution should be exercised in patients with impaired renal function (treatment should be initiated with the minimum dose), as well as in those with severe cardiovascular, gastrointestinal, or hepatic diseases.

Clinical data on the use of the drug in elderly people are lacking.

The preparation contains lactose and therefore should not be administered to patients with rare hereditary forms of galactose intolerance, lactase deficiency, or glucose-galactose malabsorption syndrome.

Alcohol consumption should be avoided during treatment.

Use during pregnancy or breastfeeding

The safety of Histafen use during pregnancy has not been established; therefore, the drug is contraindicated in women during this period.

During breastfeeding, the use of antihistamines is not recommended due to the potential for adverse effects on the central nervous system of the infant.

If it is necessary to use the drug, breastfeeding should be discontinued.

Ability to affect reaction speed when driving or operating machinery

Individuals whose work requires rapid physical and mental responses (e.g., drivers of vehicles) should first determine, by means of a short-term intake, whether the drug causes them sedative effects. If a sedative effect occurs, driving or operating machinery should be avoided.

Administration and Dosage

Take Histafen orally after meals with water.

Adults

Acute and chronic allergic disorders: 50–100 mg 2–3 times daily.

Allergic and non-allergic disorders accompanied by skin pruritus: 50–100 mg 2–3 times daily.

Therapeutic effect usually develops within 3 days after initiation of treatment. Treatment duration is 5–15 days. If necessary, the treatment course may be repeated.

Prophylaxis of allergic disorders (prior to seasonal exacerbation) and maintenance therapy: 50 mg twice daily. For prophylaxis, it is recommended to start taking the drug 2 weeks before the expected allergic reaction.

If one or more doses are missed, continue treatment with previously prescribed doses.

Children aged 12 years and older

Atopic and infectious-allergic dermatitis: 50 mg 3 times daily. Treatment course – 7 days.

Children

Histafen is indicated for use in children aged 12 years and older for atopic and infectious-allergic dermatitis.

Overdose

The drug is low in toxicity.

Symptoms: dryness of mucous membranes, headache, vomiting, abdominal pain, and other dyspeptic symptoms.

Treatment: symptomatic therapy. No specific antidote is known.

Adverse Reactions

Like all medicinal products, Histaphene may cause adverse reactions, although they do not occur in all patients.

Classification of adverse reaction frequencies: very common (≥ 1/10); common (≥ 1/100 to < 1/10); uncommon (≥ 1/1,000 to < 1/100); rare (≥ 1/10,000 to < 1/1,000); very rare (< 1/10,000).

Blood and lymphatic system disorders: rare – leukopenia.

Gastrointestinal disorders: common – dry mouth; uncommon – mild epigastric pain, dyspeptic symptoms (especially after taking the drug on an empty stomach); very rare – increased appetite.

In patients with chronic gastrointestinal disorders, the frequency of these adverse reactions increases.

Adverse reactions usually resolve within the first few days of treatment and do not require discontinuation of the drug or significant dose reduction.

Nervous system disorders: common – drowsiness (on average in 13.3% of patients), which is dose-dependent; at doses of 150 mg per day drowsiness is observed in 1.97% of patients, and at doses increased to 400 mg per day – in 24.6% of patients. In most cases, drowsiness decreases or disappears within 2–5 days after starting treatment. Histaphene may improve sleep in patients suffering from sleeplessness due to itching; uncommon – headache; rare – insomnia, psychiatric disorders (excitation) – when using the drug at high doses.

Renal and urinary disorders: rare – mild diuretic effect.

Reproductive system disorders: rare – menstrual cycle disturbances.

Shelf life

4 years.

Storage conditions

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

Keep out of reach of children.

Packaging

10 tablets in a blister. 2 blisters per cardboard box.

Supply category

Over-the-counter (without prescription).

Manufacturer

JSC "Olainfarm".

Manufacturer's address and place of business

5 Rupnicu street, Olaine, LV-2114, Latvia.