Dutch Pharmacogenetics Working Group (DPWG) guideline information
for amitriptyline and CYP2D6

last updated 08/10/2011

Summary

The Dutch Pharmacogenetics Working Group Guideline for amitriptyline recommends to select an alternative drug or monitor amitriptyline and nortriptyline plasma concentration for patients who are CYP2D6 poor or ultrarapid metabolizers. Reduce the initial dose for patients who are intermediate metabolizers or select an alternative drug.

Annotation

The Royal Dutch Pharmacists Association - Pharmacogenetics Working Group has evaluated therapeutic dose recommendations for amitriptyline based on CYP2D6 genotypes [Article:21412232]. They recommend selecting an alternative drug or reducing the initial dose for patients carrying intermediate metabolizer alleles and selecting alternative drugs or monitor amitypityline and nortriptyline plasma concentration for patients carrying the poor metabolizer or ultrarapid metabolizer alleles.

Phenotype (Genotype)Therapeutic Dose RecommendationLevel of EvidenceClinical Relevance
PM (two inactive (*3-*8, *11-*16, *19-*21, *38, *40, *42) alleles)Insufficient data to allow calculation of dose adjustment. Select alternative drug (e.g., citalopram, sertraline) or monitor amitriptyline and nortriptyline plasma concentration.Published controlled studies of moderate quality* relating to phenotyped and/or genotyped patients or healthy volunteers, and having relevant pharmacokinetic or clinical endpoints.Minor clinical effect (S): QTc prolongation (<450 ms female, <470 ms male); INR increase < 4.5; Kinetic effect (S)
IM (two decreased-activity (*9, *10, *17, *29, *36, *41) alleles or carrying one active (*1, *2, *33, *35) and one inactive (*3-*8, *11-*16, *19-*21, *38, *40, *42) allele, or carrying one decreased-activity (*9, *10, *17, *29, *36, *41) allele and one inactive (*3-*8, *11-*16, *19-*21, *38, *40, *42) allele)Reduce dose by 25% and monitor plasma concentration or select alternative drug (e.g., citalopram, sertraline).Published controlled studies of good quality* relating to phenotyped and/or genotyped patients or healthy volunteers, and having relevant pharmacokinetic or clinical endpoints.Clinical effect (S): long-standing discomfort (48-168 hr) without permanent injury e.g. failure of therapy with tricyclic antidepressants, atypical antipsychotic drugs; extrapyramidal side effects; parkinsonism; ADE resulting from increased bioavailability of tricyclic antidepressants, metoprolol, propafenone (central effects e.g. dizziness); INR 4.5-6.0; neutropenia 1.0-1.5x109/l; leucopenia 2.0-3.0x109/l; thrombocytopenia 50-75x109/l
UM (a gene duplication in absence of inactive (*3-*8, *11-*16, *19-*21, *38, *40, *42) or decreased-activity (*9, *10, *17, *29, *36, *41) alleles)Insufficient data to allow calculation of dose adjustment. Select alternative drug (e.g., citalopram,sertraline) or monitor (E-10-hydroxy)amitriptyline plasma concentration.Published controlled studies of moderate quality* relating to phenotyped and/or genotyped patients or healthy volunteers, and having relevant pharmacokinetic or clinical endpoints.Clinical effect (S): long-standing discomfort (48-168 hr) without permanent injury e.g. failure of therapy with tricyclic antidepressants, atypical antipsychotic drugs; extrapyramidal side effects; parkinsonism; ADE resulting from increased bioavailability of tricyclic antidepressants, metoprolol, propafenone (central effects e.g. dizziness); INR 4.5-6.0; neutropenia 1.0-1.5x109/l; leucopenia 2.0-3.0x109/l; thrombocytopenia 50-75x109/l.
  • *See Methods or [Article:18253145] for definition of "good" and "moderate" quality.
  • S: statistically significant difference.
  • Please see attached PDF for detailed information about the evaluated studies: Amitriptyline CYP2D6

DPWG Guideline publication

Total publications: 1

Reference
1. Pharmacogenetics: From Bench to Byte- An Update of Guidelines. Clinical pharmacology and therapeutics. 2011. Swen J J, Nijenhuis M, de Boer A, Grandia L, Maitland-van der Zee A H, Mulder H, Rongen G A P J M, van Schaik R H N, Schalekamp T, Touw D J, van der Weide J, Wilffert B, Deneer V H M, Guchelaar H-J. PubMed

Guideline History