DrugDigest: Montelukast: Information on dosage, usage, side effects, interactions, and drug comparisons, including generics when available.MedlinePlus- Montelukast: From the U.S. National Library of Medicine and National Institutes of Health. Includes information on the use of Montelukast, precations, and appropriate storage conditions.Montelukast - National Asthma Council Australia: Describes this leukotriene receptor antagonist medication, including the indications, advantages and dosage.Montelukast - UK Medicines Information: Information in PDF format, detailing efficacy, adverse effects, promotional data, and major clinical trial information. [Requires Adobe Acrobat Reader]Motelukast Sodium: Full prescribing information from RxList.Singulair: Manufacturer's site. Includes possible side effects, prescribing information and proper usage instructions.