I take Singulair daily for allergies/asthma. I’ve had it since I was a child. It’s basically a requirement for me to be an active person (gym daily), and I’ve noticed no effects in relation to candida. I’ve been on it for years.
In November, I had to add [generic] Zyrtec because I went to the allergist with a sudden outbreak of mild symptoms such as finding myself itchier, strange hives coming and going, breathing. I stopped the Zyrtec when I diagnosed myself with candida. Since pinpointing candida in January, I have no longer needed the additional Zyrtec and no more strange outbreaks.
It seems every single medication is somehow related to aggravating candida (pain medication, antihistamines, birth control, cold medicines, even marijuana). But to me, breathing freely is of vital importance.