Allegra

General information

Allegra is an anti-allergic drug belonging to the group of second-generation antihistamines. It effectively eliminates allergy symptoms, such as runny nose, sneezing and itching, due to its selective action on histamine receptors, without causing significant drowsiness.

Trade name

Allegra

International Nonproprietary Name (INN)

Fexofenadine

Form of release

The drug is available in the following forms:

• Film-coated tablets: 30 mg, 120 mg and 180 mg.
• Suspension for oral administration: 6 mg/mL (150 ml bottles).

Constitution

Acting substance

Fexofenadine (in the form of hydrochloride).

Auxiliary components

The composition varies depending on the form of release:

• Tablets: microcrystalline cellulose, pregelatinized starch, croscarmellose sodium, magnesium stearate, hypromellose (shell), polyethylene glycol, titanium dioxide.
• Suspension: sucrose, xanthan gum, sodium benzoate, citric acid, fruit flavoring, purified water.

Pharmacologic properties

Pharmacodynamics

Allegra has a pronounced antihistamine effect due to selective blocking of H1-histamine receptors located in peripheral tissues. Fexofenadine prevents the binding of histamine to these receptors, which reduces the manifestations of allergic reactions, such as swelling of mucous membranes, itching, sneezing and lacrimation. The drug effectively relieves the symptoms of seasonal allergic rhinitis and chronic urticaria, starting to act within an hour after administration and maintaining the effect for up to 24 hours.

In contrast to first-generation antihistamines, Allegra practically does not penetrate the blood-brain barrier, which minimizes sedation and does not affect cognitive functions. The drug has no significant activity against other receptors (muscarinic, adrenergic), which reduces the likelihood of side effects such as dry mouth or tachycardia. Its action is aimed solely at suppressing allergic manifestations without affecting the cause of the allergy.

Pharmacokinetics

Fexofenadine is rapidly absorbed from the gastrointestinal tract after oral administration, reaching maximum plasma concentrations in 1-3 hours. Bioavailability is about 30-40%, which is due to limited absorption and lack of first-pass effect through the liver. The intake of food, especially rich in fat, may reduce the rate of absorption, but does not affect the total absorption.

Binding to plasma proteins (mainly albumin) reaches 60-70%, and the volume of distribution is about 5.4-5.8 L/kg, indicating moderate tissue penetration. Metabolism of fexofenadine is minimal: only about 5% of the dose undergoes transformation in the liver to form inactive metabolites, the rest is excreted unchanged. The main route of excretion is through the intestine with bile (about 80%), about 10-12% is excreted by the kidneys.

The elimination half-life varies from 11 to 15 hours, which provides prolonged action after a single dose. In patients with impaired renal function (creatinine clearance less than 40 ml/min) excretion is slowed down, which may increase the concentration of the drug in the blood. In hepatic insufficiency pharmacokinetics is not significantly changed due to low degree of metabolism.

Indications for use

Diseases and conditions for which the drug is prescribed

Allegra is prescribed for the treatment of the following conditions:

• Seasonal allergic rhinitis (pollinosis) accompanied by runny nose, sneezing, itching in the nose and eyes.
• Chronic idiopathic urticaria with skin itching and rashes.
• Allergic reactions caused by pollen, dust, animal hair or other allergens (to relieve symptoms).

Contraindications

Conditions under which the use of the drug is prohibited

The use of Allegra is prohibited in the following conditions:

• Individual hypersensitivity to fexofenadine or any auxiliary components of the drug.
• Childhood under 6 years of age (for suspension) or under 12 years of age (for tablets), as safety in these groups has not been adequately studied.
• Severe renal insufficiency (creatinine clearance less than 10 ml/min) without dose adjustment.

How to use and dosage

How to take

Allegra is taken orally, preferably on an empty stomach or 1 hour before a meal to avoid slow absorption. Tablets should be swallowed whole, drinking enough water (100-150 ml). The suspension should be shaken before use, measure the required dose with a measuring spoon or cup and drink water.

Dosages for adults and children

Adults

Dosage depends on the indication:

• Seasonal allergic rhinitis: 120 mg or 180 mg once daily.
• Chronic urticaria: 180 mg once daily.

Children

Dosage is determined by age and body weight:

• Children 6-11 years of age (suspension): 30 mg (5 ml) twice daily.
• Children over 12 years of age (tablets): 120 mg or 180 mg once daily as in adults.

Dose adjustment for certain conditions

In renal insufficiency (creatinine clearance 10-50 ml/min), the initial dose is reduced: for adults - to 60 mg once daily, for children 6-11 years - to 30 mg once daily. In severe renal insufficiency (clearance less than 10 ml/min) the drug is contraindicated. In hepatic insufficiency no dose adjustment is required, as metabolism of fexofenadine is minimal.

Side effects

Possible adverse reactions of the body

The following adverse reactions may occur during the use of Allegra:

• Nervous system side: headache, drowsiness, fatigue, dizziness.
• Side of the digestive system: nausea, dry mouth, abdominal discomfort.
• Allergic reactions: skin rash, itching, rarely - urticaria.
• Respiratory system: dryness of nasal mucosa, sore throat.
• Other: insomnia, palpitations (in rare cases).

Overdose

Symptoms of overdose

The following symptoms may occur if the recommended dose of Allegra is exceeded:

• Exacerbation of side effects: pronounced drowsiness, dizziness, headache.
• Side of the digestive system: dry mouth, nausea.
• Cardiovascular disorders: palpitations (in rare cases).

First aid measures

In case of suspected overdose it is necessary:

1. Stop taking the drug.
2. Seek medical attention.
3. Rinse the stomach, if the intake has occurred recently (within 1-2 hours).
4. Give activated charcoal (1 g/kg body weight) to reduce absorption.
5. Provide symptomatic support: control of the patient's condition and observation until normalization.

Interaction with other drugs

Effects on the effects of other medications

Allegra has minimal interactions with other medications, but some combinations require attention:

• Antacids containing aluminum or magnesium (e.g., aluminum hydroxide) reduce the absorption of fexofenadine; a 2-hour interval between doses is recommended.
• Inhibitors of P-glycoprotein (e.g., ketoconazole, erythromycin) may increase the concentration of the drug in the blood, intensifying its effect.
• No significant effect on the metabolism of drugs dependent on the cytochrome P450 system, such as theophylline or warfarin.

Compatibility with alcohol and food

Alcohol consumption in conjunction with Allegra does not enhance the sedative effect of the drug, but may exacerbate allergy symptoms such as headache or fatigue, so avoidance of alcohol is recommended. Food, especially fatty foods, slows the absorption of fexofenadine, so it is better to take the drug on an empty stomach to maximize its effectiveness.

Special Instructions

Use in pregnancy and breastfeeding

Allegra is used during pregnancy only if the benefit to the mother outweighs the potential risk to the fetus, as safety data are limited. Fexofenadine penetrates the placental barrier in minimal amounts, but its effect on fetal development is not sufficiently studied. The drug is excreted with breast milk, therefore its use is not recommended during lactation; if treatment is necessary, feeding should be temporarily discontinued.

Effects on driving and mechanisms

Allegra usually does not cause drowsiness, but some patients may experience side effects such as fatigue or dizziness, especially at the beginning of administration. It is recommended to refrain from driving vehicles or working with mechanisms until the individual reaction to the drug is assessed.

Particulars of use in the elderly and children

In elderly patients Allegra is used in standard doses, but in the presence of renal insufficiency dosage correction is required due to slow excretion. In children the drug is used from 6 years of age (suspension) or from 12 years of age (tablets), and the dosage is adjusted for age and body weight to ensure safety and efficacy.