Rupatadine

Rupatadine is an active substance from the group of H₁-antihistamines(selective histamine H1 receptor antagonist) and an inhibitor (antagonist) of platelet-activating factor (PAF) used for the symptomatic treatment of hay fever (allergic rhinitis).

Indications and use

Rupatadine is a second-generation H₁-antihistamine and chemically belongs to azines. It is used for symptomatic relief of the nasal and non-nasal symptoms of seasonal allergic rhinitis and perennial allergic rhinitis in patients 2 years of age and older. In addition, it is also used for the symptomatic relief of chronic spontaneous urticaria.

Usually, rupatadine is used in the form of tablets when used for adults and as a juice when used for children. Standard dosages are 10 mg in tablets and 1 mg/ml in oral solution.

Rupatadine is dispensed only against a doctor's prescription.

History

The initial synthesis, preclinical and clinical development of rupatadine was carried out by GRUPO J. URIACH, S.L, a Spanish pharmaceutical company. It was launched in Spain in 2003 under the brand name Rupafin.

Pharmacology and mechanism of action

Rupatadine is a drug with a dual mechanism of action. On the one hand, rupatadine blocks H₁-receptors, preventing histamine from binding to them, and on the other hand, it inhibits the platelet activating receptor (PAF). In an allergic reaction, mast cells degranulate and release histamine and other substances. Histamine acts on H₁-receptors and causes symptoms such as nasal congestion, rhinitis, itching and swelling. PAF is formed from phospholipids that are cleaved by phospholipase A2. It causes blood vessels to become more permeable, contributing to nasal discharge and nasal congestion. By blocking both the H₁-receptor and the PAF receptor, rupatidine prevents these mediators from exerting their effects, thereby reducing the severity of allergic symptoms.

Pharmacokinetics

Rupatidine is rapidly absorbed and reaches maximum plasma concentration after approximately one hour. Administration with a high-fat meal may increase absorption. Rupatidine is 99% bound to plasma proteins in the blood. Rupatadine is metabolized by oxidation mediated primarily by CYP3A4 in the liver. CYP2C9, CYP2C19, and CYP2D6 are also involved to a lesser extent. The half-life in adults is approximately 6 hours. In children, this can be significantly longer at 10 -15 hours.

Drug Interactions

Interactions may occur, especially when taken concomitantly with substances that inhibit or induce the CYP3A4 enzyme. These include:

• Ketoconazole, Voriconazole
• Grapefruit juice
• erythromycin and related substances
• Drugs from the statin group

Contraindications

If allergy to rupatadine is known, its use is strictly contraindicated.

Side effects

Since Rupatadine is a second-generation antihistamine, it does not actually have a soporific (sedative) effect. However, there are cases in which the occurrence of drowsiness has been reported as a side effect. However, controlled studies have shown that there is no difference here compared to a placebo administered.

Other possible side effects are:

• Headache
• Fatigue
• Dry mouth
• Nausea
• abdominal pain
• Vomiting
• Gastrointestinal discomfort
• muscle and joint pain
• fever
• Weight gain
• Cough
• Nosebleeds

Pregnancy and breastfeeding

Before taking during pregnancy or breastfeeding, a physician should be contacted, if possible, who will weigh the risk-benefit ratio.