Provided herein are spiro-cyclic compounds, methods of synthesis, and methods of use thereof. The compounds provided herein are useful for the treatment, prevention, and/or management of various disorders, including, e.g., neurological disorders and metabolic disorders. Compounds provided herein inhibit the activity of histamine H3 receptors and modulate the release of various neurotransmitters, such as, e.g., histamine, acetylcholine, norepinephrine, and dopamine (e.g. at the synapse). Pharmaceutical compositions containing the compounds and their methods of use are also provided herein.