DYSPORT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DYSPORT (DYSPORT).
Botulinum toxin type A inhibits acetylcholine release at the neuromuscular junction by cleaving SNAP-25, a protein required for synaptic vesicle fusion, thereby causing temporary muscle paralysis.
| Metabolism | Metabolized via proteolytic degradation; not dependent on cytochrome P450 enzymes. |
| Excretion | Primarily eliminated via hepatic metabolism, with inactive metabolites excreted renally (approximately 3-10% unchanged) and fecally (minor). Biliary excretion is negligible. |
| Half-life | Terminal elimination half-life is approximately 10-12 hours for the complex; however, clinical duration is longer due to prolonged pharmacodynamic effects. The half-life has limited clinical relevance as recovery from neuromuscular blockade depends on neural sprouting and receptor turnover. |
| Protein binding | Minimal protein binding (<5%), primarily to albumin. The toxin complex does not significantly bind to plasma proteins. |
| Volume of Distribution | Approximately 0.5-1.0 L/kg, reflecting limited distribution beyond the extracellular space and localized action at neuromuscular junctions. The Vd is not clinically meaningful due to site-specific injection. |
| Bioavailability | Absorption after intramuscular injection is negligible systemically (local effect). Bioavailability is not applicable for oral or other routes; the drug is only used parenterally. Systemic bioavailability from intramuscular injection is <1% due to high local retention. |
| Onset of Action | Intramuscular: 24-72 hours for clinical effect in dystonia, with peak effect at 1-2 weeks. In therapeutic use, effects are not immediate. |
| Duration of Action | Duration of clinical effect is 3-4 months in most indications (e.g., cervical dystonia, glabellar lines). Repeat injections are typically required every 12-16 weeks. Duration is dose-dependent and may be shorter with repeated use due to antibody formation. |
For cervical dystonia: 500 Units intramuscularly divided among affected muscles, repeat no sooner than every 12 weeks. For glabellar lines: 50 Units intramuscularly divided into 5 injection sites, repeat no sooner than every 3 months. For blepharospasm: 1.25-2.5 Units per injection site, total dose not to exceed 100 Units per eye per 3 months.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No specific Child-Pugh based dose modifications; use caution in severe hepatic impairment due to potential systemic effects. |
| Pediatric use | For pediatric cervical dystonia (≥2 years): 6-12 Units/kg intramuscularly, divided among affected muscles, not to exceed 500 Units total per session; repeat no sooner than every 12 weeks. |
| Geriatric use | No specific dose adjustment; however, elderly patients may have reduced muscle mass and increased susceptibility to adverse effects; consider lower initial doses and gradual titration. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DYSPORT (DYSPORT).
| Breastfeeding | Unknown if excreted in human milk. Manufacturer advises caution; no M/P ratio available. Consider risk of infant botulism; avoid breastfeeding or discontinue drug based on importance to mother. |
| Teratogenic Risk | FDA Pregnancy Category C. Animal studies have shown adverse effects on fetal development (reduced fetal weight, skeletal ossification delays). No adequate human studies. Risk cannot be ruled out; use only if potential benefit justifies potential risk. First trimester: highest risk for major malformations; second/third trimester: risk of fetal growth restriction and preterm labor. |
■ FDA Black Box Warning
Dysport may cause distant spread of toxin effects, resulting in botulism-like symptoms including respiratory compromise and death. Risk is highest in children with cerebral palsy treated for spasticity, but can occur in adults and other conditions.
| Common Effects | Tiredness Weakness Flu like symptoms Injection site reactions pain swelling redness |
| Serious Effects |
["Hypersensitivity to botulinum toxin type A or any component of the formulation","Infection at the proposed injection site(s)","Intended intramuscular injection in patients with known coagulopathy (relative)"]
| Precautions | ["Distant spread of toxin effect","Respiratory compromise","Dysphagia","Risk of anaphylaxis","Use caution in patients with neuromuscular disorders (e.g., myasthenia gravis, ALS)","Avoid in patients with known hypersensitivity to any ingredient","Risk of infection at injection site","Use with caution in patients with compromised respiratory status","Overdose can cause severe weakness and paralysis"] |
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| Fetal Monitoring | Monitor for signs of systemic spread (dysphagia, respiratory compromise) and local injection reactions. Fetal monitoring: ultrasound for growth and anatomy if exposure during pregnancy. Monitor for preterm labor and fetal movement. |
| Fertility Effects | Animal studies: no effect on male or female fertility. Human data limited; theoretical risk of impaired fertility due to muscle paralysis if used in pelvic region. No significant impact on reproductive hormones. |