How long does it take for singulair (montelukast) to be effective?

2: Singulair (montelukast) can be effective in as few as 2 hours. For patients with exercise induced asthma should take singulair (montelukast) at least 2 hours before exercise to be able to feel the effect of the medication. Because of the inflammatory nature of asthma in most other cases it can take several days to achieve full benefit of the singulair (montelukast).

After the first dose: The onset of effect occurs with the first dose and lasts for about 24 hours. Clinical trials show continued effectiveness for the entire year of the study. Withdrawal does not cause rebound of symptoms.

Hours to days: While the effects of singulair (montelukast) are generally noticed within the first couple of hours after taking the first pill, it can sometimes take a couple of days to experience the full effects. This is because singulair (montelukast) works by blocking an allergy chemical in the body (leukotrienes) which is made later in the course of the allergic reaction and associated with long-term allergy inflammation.