Private practice symptoms and conditions

I am a paediatrician in private practice. I recently put an 8yr old boy with moderte to severe asthma on singulair. He is also epileptic and is on lamictin. After starting the singulair he experienced intense headaches, dizziness and blurred vision.
The headches were associated with vomiting. I have subsequently stopped the singulair but was really surprised by these side effects. Could it be related to his epilepsy? I have been using singulair for many years but this is the first case that I have seen with these side effects.

I am a Rheumatologist at private practice in PR. I was consulted on a patient who is recently diagnosed as pneumonitis, biopsy report is compatible with pneumonitis and refers it could be hypersensitivity pneumonitis or collagen disease. The patient refers that after she started singulair she noticed swelling of hands and general malaise that dissapeared when she D/C it. This happened by the same time as the pneumonitis. Has pneumonitis been reported with Singulair?