Used off-label as a treatment for nocturnal leg cramps
Safety
Adverse Effects
Cinchonism: tinnitus, high-tone hearing loss, photophobia and other visual disturbances, dysphoria, headache, nausea, vomiting, sweating, dizziness and postural hypotension
Hypoglycemia, from pancreatic β cell stimulation
Hypotension, usually from IV infusion
Hearing and visual disturbances, including irreversible loss
Gastrointestinal symptoms
Cutaneous effects
Mild QT prolongation (rare unless plasma levels are elevated) and arrhythmias
Hemolysis (in patients with G6PD deficiency or with hypersensitivity)
References
^David B. Hogan. Quinine: not a safe drug for treating nocturnal leg cramps. Canadian Medical Association Journal. 2015;187(4):237-238. doi:10.1503/cmaj.150044.