Head tremors could be also a side-effect, as it is consistent
with the possible side effects presented
with the use of Singulaire, however, not directly listed itself as one, but rather linked to one ( seizures, dizziness, headaches, etc).
It should be reported to your prescribing Doctor immediately.
Please offer more details such as reasons for taking it and other symptoms.
There may be better options available.
Take care.