Math-free guides for glycerin and allergens at variable subcutaneous injection volumes: How's my dosing? Update

Current summaries of effective maintenance dose ranges for subcutaneous immunotherapy (SCIT) are based on administration of 0.5-mL volumes. Extract formulations delivering equivalent dose ranges for practices using different injection volumes have not been reported, and calculation of the final glycerin concentrations in these solutions remains an inconvenient and repetitive process.

To create math-free guides for allergen doses and glycerin concentrations that identify the extract concentrate volumes required to deliver doses within the ranges cited in the 2011 immunotherapy practice parameters for clinicians using 5.0-mL maintenance vials and injection volumes ranging from 0.2 to 1.0 mL.

Algebraic calculations were performed to determine the specific combinations of extract concentrate strengths, volumes of these products in patient vaccines, and injection volumes needed for administration of target allergen doses spanning the current SCIT practice parameter recommendations.

For each product or group (nonstandardized extracts), tables were constructed to define the allergen doses provided by various combinations of extract concentrate volumes and injection volumes. The values within the effective dose ranges for each product were highlighted to facilitate comparisons of specific conditions relevant to allergy specialists. Glycerin tables were also created to permit convenient assessments of the final concentrations of this stabilizer in patient prescriptions.

SCIT dosing and glycerin tables are useful tools to assist allergists with practice decisions that involve variable patient formulas and injection volumes and can help identify suitable conditions for treatment of patients presenting with diverse allergen sensitivities and specificity profiles.