ENA-001 (formerly GAL-021) is a drug related to almitrine which acts as a respiratory stimulant, with its mechanism of action primarily thought to involve blocking the BK<sub>Ca</sub> potassium channel, although secondary mechanisms may also be involved. It was developed by Galleon Pharmaceuticals, and is being tested in clinical trials for potential uses in post-operative care, as well as more generally to counteract the respiratory depression which can be a side effect of opioid analgesic drugs.