What TPMT/NUDT15 genotype requires dose reduction?

TPMT intermediate metabolizers (1 functional allele): reduce dose 30-70%; poor metabolizers (0 functional alleles): reduce dose 90% or switch to alternative; NUDT15 poor metabolizers require >10-fold dose reduction to avoid severe myelosuppression.

What AZA dose is used for IBD maintenance?

IBD (Crohn’s, UC): azathioprine 2.0-2.5 mg/kg/day or mercaptopurine 1.0-1.5 mg/kg/day; start low (25-50 mg/day), increase over 4-8 weeks to maintenance; check CBC every 2-4 weeks for first 3 months.

What thiopurine metabolites guide dosing?

6-thioguanine nucleotides (6-TGN) therapeutic range 230-450 pmol/8×10⁸ RBC for IBD; 6-methylmercaptopurine (6-MMP) <5700 to avoid hepatotoxicity; shunting to 6-MMP (leukopenia without therapeutic 6-TGN) treated with dose reduction + allopurinol 100 mg/day.

What CBC changes indicate AZA myelosuppression?

WBC 50% from baseline warrants immediate dose reduction regardless of absolute value.

What is the allopurinol-AZA combination therapy?

Low-dose AZA (25-50% normal dose) + allopurinol 100 mg/day shifts metabolism from 6-MMP to 6-TGN; used in patients who shunt to 6-MMP, achieving therapeutic 6-TGN at lower AZA doses; xanthine oxidase inhibition prevents purine degradation.

Azathioprine TPMT/NUDT15 Pharmacogenomics Dose Calculator

Calculates azathioprine/mercaptopurine dose based on TPMT and NUDT15 genotype per CPIC guidelines, starting dose for IBD (2-2.5 mg/kg/day) and autoimmune disease, and thiopurine metabolite monitoring.

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Azathioprine TPMT/NUDT15 Pharmacogenomics Dose Calculator

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Frequently Asked Questions

What TPMT/NUDT15 genotype requires dose reduction?

What AZA dose is used for IBD maintenance?

What thiopurine metabolites guide dosing?

What CBC changes indicate AZA myelosuppression?

What is the allopurinol-AZA combination therapy?