From the Research
Myobloc (botulinum toxin type B) should be used for dynamic rhytides at a dose of 2500 units, divided among five standardized intramuscular sites, for optimal efficacy and safety, as evidenced by the study published in Dermatologic surgery 1. The use of Myobloc for dynamic rhytides is supported by several studies, including one that demonstrated its effectiveness in treating glabellar rhytides refractory to botulinum toxin type A 1.
- Typical dosing ranges from 1000-2500 units total, with specific amounts varying by treatment area.
- The onset of action is typically faster than type A toxins (1-3 days versus 3-7 days), but the duration is shorter (8-10 weeks versus 3-4 months) 2.
- Myobloc has a lower pH (5.6) than type A toxins, which may cause more injection site pain, and a higher diffusion rate, requiring careful technique to avoid affecting adjacent muscles 3.
- Practitioners should note that Myobloc's units are not equivalent to Botox units (approximately 50:1 ratio), so dosing calculations must be adjusted accordingly 4. Key considerations for using Myobloc include:
- Careful patient selection, as it is generally reserved for patients who have developed resistance to type A toxins.
- Precise injection technique to minimize the risk of adverse effects.
- Monitoring for potential side effects, such as injection site pain, bruising, and frontal brow tightness 1.