SAO PAULO (AP) — The 4-year-old boy struggled to balance while walking through the living room. His mother’s eyes attentively followed his every move. Then a seizure knocked him to the ground, the dull thud of his small body echoing through the home.

On this July morning in Guaruja, a coastal city in Brazil's state of Sao Paulo, Murillo quickly regained his senses as his mom, Janaína Silva, cradled him. “From five minutes of agony, it’s now just seconds," Silva said, recalling how only three months ago her son’s seizures would have lasted much longer. Murillo was diagnosed as a baby with Lennox-Gastaut syndrome , a type of epilepsy with multiple types of seizures that cause stiffening and dropping of the head and limbs.

His shorter — and less intense — seizures are a result of a steady dose of liquid cannabidiol (CBD) that Silva can acquire for free through the state public health system. It's a step the federal government has failed to take, as legislation to regulate medical cannabis at the national level has stalled in Congress for years. In drugstores, a 30 milliliter bottle (1 fluid ounce) of the CBD that Murillo’s pediatrician prescribed for his condition costs as much as 900 reais ($180) — more than half Silva’s monthly wages as an office assistant.

Since June, she has spent zero on Murillo’s CBD medication. Twice a day, she drips the oil into the boy's mouth, and each bottle lasts about 45 days. Sao Paulo, Brazil’s most populous state with ov.