Letybo contraindications include known hypersensitivity to any botulinum toxin preparation or to any of the components in the Letybo formulation and infection at the injection site.

Spread of toxin effects; swallowing and breathing difficulties can lead to death. Seek immediate medical attention if respiratory, speech or swallowing difficulties occur. The potency Units of Letybo are not interchangeable with other preparations of botulinum toxin products. Potential serious adverse reactions after Letybo injections for unapproved uses. If a hypersensitivity reaction occurs, discontinue Letybo and immediately initiate appropriate therapy. Adverse reports have been received involving the cardiovascular system, some with fatal outcomes. Use caution when administering to patients with pre-existing cardiovascular disease. Concomitant neuromuscular disorder may exacerbate clinical effects of treatment. Use with caution in patients with compromised respiratory function or dysphagia.

Co-administration of Letybo and aminoglycosides, anticholinergic agents, or any other agents that interfere with neuromuscular transmission may potentiate the effect of Letybo; co-administer only with caution and close observation.

Letybo is not recommended for use in children, pregnant or lactating women.