Gazan officials said five people died in the critical care unit, and the Israeli military announced the arrests of 20 people in the hospital who it said had participated in the Oct. 7 attacks.
Singulair, now a generic, is still used by millions of people in the United States even after thousands of patients and dozens of studies have described harm.
A lack of clean water, toilets and food have fueled a spike in illnesses, and increasingly dire conditions are making it hard for the sick to recover, health officials say.