Ping Hua, Xing Wang, Jie Chen, Weiguo Liu, RuiJuan Sha, WeiWei Jiang
Zoletil 50 inhalation is associated with a broad spectrum of neurological and systemic injury, with tremor, ataxia, and visual disturbance as the most consistent features. Relapse is common and early; one-third of long-term survivors still had neurological deficits at two years. Clinicians should consider tiletamine-zolazepam exposure when evaluating young patients with unexplained tremor, ataxia, and perceptual disturbance as standard toxicology screens do not detect this compound. Prospective controlled studies are needed to confirm causation and define the full spectrum of toxicity.
BACKGROUND: Tiletamine-zolazepam (Zoletil) is a veterinary anesthetic, which is increasingly being abused by humans. However, the chronic neurotoxicity of this compound in humans and its long-term clinical outcomes have rarely been reported.
OBJECTIVE: To characterize the neurological and systemic injury following recreational Zoletil 50 inhalation, including relapse behavior and persistent deficits.
METHODS: We performed a retrospective case series of patients presenting to our institution with Zoletil 50 toxicity. We analyzed the clinical features, laboratory results, and neuroimaging findings, and assessed long-term outcomes and relapse rates during a two-year observation period.
RESULTS: All 36 subjects (100%) demonstrated postural tremor, with 22 (61.1%) showing sustained, high-amplitude tremor early after admission. Four patients (11%) presented with bradykinesia and rigidity. Cerebellar ataxia was present in 30 (83%), visual disturbance in 20 (56%), and concomitant hallucinations in 16 (44%). Biochemical abnormalities included elevated transaminases (53%) and hypokalemia (44%). Two patients died in hospital due to cardiorespiratory failure. Of 34 discharged patients, 20 (59%) relapsed, 17 within the first month. A third death occurred during follow-up after a fifth relapse. At two years, residual deficits persisted in 11 of 33 survivors: subjective memory decline in seven, visual impairment in six, and bradykinesia requiring levodopa in two.
CONCLUSIONS: Zoletil 50 inhalation is associated with a broad spectrum of neurological and systemic injury, with tremor, ataxia, and visual disturbance as the most consistent features. Relapse is common and early; one-third of long-term survivors still had neurological deficits at two years. Clinicians should consider tiletamine-zolazepam exposure when evaluating young patients with unexplained tremor, ataxia, and perceptual disturbance as standard toxicology screens do not detect this compound. Prospective controlled studies are needed to confirm causation and define the full spectrum of toxicity.