Pharmacological action of Claritin

Antiallergic drug, selective blocker of peripheral histamine H1receptors. Loratadine is a tricyclic compound with a pronounced antihistamine effect. Possesses fast and long-term anti-allergic action.

Loratadine does not penetrate the BBB and does not affect the central nervous system. Has no clinically significant anticholinergic or sedative effect, i.e. does not cause drowsiness and does not affect the speed of psychomotor reactions when used in recommended doses. Taking Claritin® does not lead to prolongation of the QT interval on the ECG. With long-term treatment, there were no clinically significant changes in vital signs, physical examination data, laboratory results or ECG.

Loratadine has no significant selectivity for histamine H2receptors. Does not inhibit the reuptake of norepinephrine and has virtually no effect on the cardiovascular system or pacemaker function.

After oral administration of Claritin®, the onset of action is within 30 minutes. The antihistamine effect reaches its maximum after 8-12 hours from the onset of action and lasts more than 24 hours.

Pharmacokinetics

Absorption

After oral administration, loratadine is rapidly and well absorbed from the gastrointestinal tract. Tmax in the blood plasma loratadine - 1-1.5 hours, while its active metabolite desloratadine -. Ingestion of 1.5-3.7 h Tincreasesmax loratadine and desloratadine of about 1 hour, but no effect on drug efficacy. The Cmax of loratadine and desloratadine does not depend on food intake.

The bioavailability of loratadine and its active metabolite is dose-dependent.

Distribution

Loratadine is highly associated with plasma proteins 97-99%, and its active metabolite is moderately 73-76%.

Metabolism

Loratadine is metabolized to desloratadine with the participation of the isoenzyme CYP3A4 and, to a lesser extent, CYP2D6.

Excretion

It is excreted by the kidneys (approximately 40% of the oral dose) and through the intestine (approximately 42% of the oral dose) for more than 10 days, mainly in the form of conjugated metabolites. Approximately 27% of an oral dose is excreted by the kidneys within 24 hours after taking the drug. Less than 1% of the active substance is excreted unchanged by the kidneys within 24 hours after taking the drug.

T1/2 of loratadine ranges from 3 to 20 hours (on average 8.4 hours), and desloratadine - from 8.8 to 92 hours (on average 28 hours).

Pharmacokinetics in special clinical situations

The pharmacokinetic profiles of loratadine and its active metabolite in adult and elderly healthy volunteers were comparable.

T1/2 of loratadine and desloratadine in elderly patients is, respectively, from 6.7 to 37 hours (on average 18.2 hours) and from 11 to 39 hours (on average 17.5 hours).

In patients with chronic kidney disease, Cmax and AUC of loratadine and its active metabolite are increased compared with patients with normal renal function. T1/2 of loratadine and its active metabolite does not differ from those in healthy patients. T1/2 of loratadine and its active metabolite does not change in the presence of chronic renal failure. Hemodialysis in patients with chronic renal failure has no effect on the pharmacokinetics of loratadine and its active metabolite.

In patients with alcoholic liver damage, Cmax and AUC of loratadine and its active metabolite increase 2 times compared with these indicators in patients with normal liver function. T1/2 of loratadine and its active metabolite increases with alcoholic liver damage (depending on the severity of the disease) and does not change in the presence of chronic renal failure.

Indications for Claritin®

• Sseasonal (hay fever) and year-round allergic rhinitis and allergic conjunctivitis (to eliminate symptoms associated with these diseases - sneezing, itching of the nasal mucosa, rhinorrhea, burning and itching in the eyes, lacrimation);
• chronic idiopathic urticaria;
• allergic skin diseases.

Dosage regimen

The drug is administered orally, regardless of food intake.

Adults (including elderly patients) and adolescents over the age of 12 years are recommended to take Claritin at a dose of 10 mg (1 tab. Or 2 teaspoons / 10 ml / syrup) 1 time / day.

For children aged 2 to 12 years, a dose of Claritin is recommended to be prescribed depending on body weight: with a body weight of less than 30 kg - 5 mg (1/2 tab. Or 1 teaspoon / 5 ml / syrup) 1 time / day, with a weight body 30 kg or more - 10 mg (1 tab. or 2 teaspoons / 10 ml / syrup) 1 time / day.

For adults and children weighing more than 30 kg with severe liver dysfunction, the initial dose is 10 mg (1 tab. Or 2 teaspoons / 10 ml / syrup) every other day, with a body weight of 30 kg or less - 5 mg (1 teaspoon spoon / 5 ml / syrup) every other day.

In elderly patients and in patients with chronic renal failure, dose adjustment is not required.

Application during pregnancy and lactation 

The safety of loratadine during pregnancy has not been established. The use of Claritin® during pregnancy is possible only if the intended benefit to the mother outweighs the potential risk to the fetus.

Loratadine and its active metabolite are excreted in breast milk, therefore, when prescribing the drug during lactation, it is necessary to decide on the termination of breastfeeding.

Application for violations of liver function

Use the drug with caution in liver failure: the initial dose should be 10 mg (1 tab. Or 2 teaspoons / 10 ml / syrup) every other day.

Application for impaired renal function

For patients with renal insufficiency, the initial dose should be 10 mg (1 tab. Or 2 teaspoons / 10 ml / syrup) every other day.

Use in children

Contraindications: age up to 2 years (for syrup); age up to 3 years (for tablets).

Claritin recommended for children aged 2 to 3 years® syrup is.

Special instructions

Reception of the drug Claritin® should be discontinued 48 hours before the skin tests, since antihistamines can distort the results of a diagnostic study.

Use in Pediatrics

Children aged 2 to 3 years are advised to take the drug Claritin® in the form of a syrup.

Influence on the ability to drive vehicles and control mechanisms

No negative effect of Claritin Revealed® on the ability to drive or perform other activities requiring increased concentration of attention has been. However, in very rare cases, some patients experience drowsiness while taking Claritin®, which may affect their ability to drive vehicles and operate machinery.

Overdose

Symptoms: drowsiness, tachycardia, headache.

Treatment: gastric lavage, intake of adsorbents (crushed activated carbon with water), symptomatic and supportive therapy. Loratadine is not excreted by hemodialysis. After providing emergency care, it is necessary to continue monitoring the patient's condition.

Drug interaction

Claritin® does not enhance the effect of ethanol (alcohol) on the central nervous system.

When Claritin was taken together with ketoconazole, erythromycin or cimetidine, an increase in the concentration of loratadine in plasma was noted, but this increase was not clinically significant, incl. according to ECG data.

Side effect

In clinical trials

In clinical trials involving children aged 2 to 12 years who took Claritin®, headache (2.7%), nervousness (2.3%), fatigue (1%) were observed more often than in the placebo group ...

From the nervous system: in children aged 2 to 12 years - headache (2.7%), nervousness (2.3%), fatigue (1%); in adults - headache (0.6%), drowsiness (1.2%), insomnia (0.1%).

From the digestive system: in adults - increased appetite (0.5%).

In the post-marketing period

On the part of the nervous system: very rarely (<1/10 000) - dizziness, fatigue.

On the part of the digestive system: very rarely (<1/10 000) - dry mouth, gastrointestinal disorders (nausea, gastritis), abnormal liver function.

Allergic reactions: very rarely (<1/10 000) - rash, anaphylaxis.

From the side of the cardiovascular system: very rarely (<1/10 000) - palpitations, tachycardia.

On the part of the skin: very rarely (<1/10 000) - alopecia.