LTRA

Leukotriene receptor antagonists (LTRA) are a class of anti-inflammatory medications used in the management of asthma and allergic rhinitis. They act by selectively blocking the cysteinyl leukotriene receptor CysLT1, reducing leukotriene-mediated bronchoconstriction, mucus production, and airway inflammation.

Common LTRAs include montelukast, zafirlukast, and pranlukast. Montelukast is widely prescribed and available in daily oral formulations; zafirlukast and pranlukast are used in some regions but are less common today due to safety concerns and drug interaction profiles, especially with zafirlukast.

Indications include add-on therapy to inhaled corticosteroids for mild to moderate persistent asthma, prevention of exercise-induced bronchoconstriction, and treatment of perennial or seasonal allergic rhinitis. They are not intended for treating acute asthma attacks and are usually used regularly to achieve control.

Pharmacology and administration: LTRAs are oral agents with a favorable safety profile compared with some other asthma therapies. Clinical effects may take days to weeks to become evident. Dosing is typically age-based and guided by the prescriber.

Safety and interactions: most people tolerate LTRAs well. Common adverse effects are headache and abdominal pain; rare neuropsychiatric events such as mood changes or agitation have been reported, particularly in younger patients. Zafirlukast and pranlukast can interact with hepatic enzymes and influence levels of drugs such as warfarin and theophylline; montelukast has fewer clinically significant interactions. Liver monitoring is advised with those that have hepatic risk and therapy should be stopped if serious adverse effects occur.

History and regulation: LTRAs were developed in the late 20th century. Marketed agents include montelukast (Singulair) and zafirlukast (Accolate); pranlukast is used in some countries. They are recommended as adjuncts in asthma management guidelines and as alternatives to low-dose inhaled corticosteroids in selected patients.