Does Singulair expire? 

Does Singulair expire? 

Yes, Singulair does expire. You can find the expiry date on the packaging of your medication, which is commonly dated 3 years from the manufacturing date. 

However, Singulair (Montelukast) can be used safely after it has expired. A recent research study took samples from expired Montelukast and the potency of the medication was determined by using HPLC. 

The results were quite promising as the expired drug was more than 90% potent after 3 to 5 years (1). This provides enough evidence that Singulair can be used safely after 3-5 years of its expiry. 

What are the possible dangers associated with the use of expired Singulair? 

As I just stated, it’s absolutely safe to use expired Singulair for 3-5 years. However, if your Singulair expired longer than 5 years ago, there is no evidence available to predict its safety and efficacy. It’s best to discard it. 

What to do if you have taken an expired Singulair? 

There’s nothing to worry about if you have taken an expired Singulair. In fact, you can continue to take it for your condition and it will deliver the therapeutic response you desire. 

However, if you feel like your Singulair is failing to help you with your symptoms, consult your healthcare provider. 

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Kutty RG, Bevry M, Hoffmann P, Abourashed EA. Determination of albuterol and montelukast post-expiry drug strength by HPLC. Heliyon. 2022 Aug 5;8(8):e10104. doi: 10.1016/j.heliyon.2022.e10104. PMID: 36016533; PMCID: PMC9396548. Available from: