PMID- 10711864
OWN - NLM
STAT- MEDLINE
DCOM- 20000320
LR  - 20131121
IS  - 0022-2143 (Print)
IS  - 0022-2143 (Linking)
VI  - 135
IP  - 3
DP  - 2000 Mar
TI  - Relationship between red cell mean corpuscular volume and 6-thioguanine 
      nucleotides in patients treated with azathioprine.
PG  - 256-62
AB  - Azathioprine (AZA) is characterized by high interindividual differences in 
      bioavailability and metabolization. The aim of the present study was to analyze, 
      in patients treated with AZA for various immune system disorders, whether the 
      variation in red blood cell mean corpuscular volume (deltaMCV) could be used as 
      an indirect estimation of the level of the active immune modifier metabolite 
      6-thioguanine nucleotides (6-TGN). In 43 consecutive patients treated with a 
      stable dose of AZA for at least 6 months who were not initially anemic, the 
      erythrocyte 6-TGN levels with routine hematologic parameters were determined two 
      to four times at 1-month intervals. In most patients MCV significantly increased 
      after 3 months of therapy and stabilized after 6 months. The correlation between 
      the daily dose of AZA and the 6-TGN level was mild (r = 0.51; P<.001). A weak 
      correlation was also found between the dose of AZA and the deltaMCV after at 
      least 6 months of therapy (r = 0.36; P<.05). The correlation between deltaMCV and 
      6-TGN level, however, was much better (r = 0.74; P<.001). The lack of a 
      significant increase in MCV after 3 to 4 months of AZA therapy reflects low 6-TGN 
      levels, sometimes a result of undertreatment. A determination of the 6-TGN level 
      during the first months after AZA therapy is begun will allow more accurate 
      adaptation of the effective dose. We observed that deltaMCV could be used as an 
      indicator of 6-TGN levels after 6 months of AZA treatment. An increase in MCV of 
      at least 6 fL is expected to reflect a 6-TGN level of about 175 pmol/8x10(8) red 
      blood cells (probably being within a therapeutic value).
FAU - Decaux, G
AU  - Decaux G
AD  - Service de Medecine Interne Generale, Hopital Universitaire Erasme, Bruxelles, 
      Belgium.
FAU - Prospert, F
AU  - Prospert F
FAU - Horsmans, Y
AU  - Horsmans Y
FAU - Desager, J P
AU  - Desager JP
LA  - eng
PT  - Case Reports
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Lab Clin Med
JT  - The Journal of laboratory and clinical medicine
JID - 0375375
RN  - 0 (Guanine Nucleotides)
RN  - 0 (Immunosuppressive Agents)
RN  - 0 (Thionucleotides)
RN  - MRK240IY2L (Azathioprine)
SB  - IM
MH  - Adult
MH  - Azathioprine/blood/pharmacokinetics/*therapeutic use
MH  - Biological Availability
MH  - Churg-Strauss Syndrome/blood/drug therapy
MH  - Erythrocyte Indices
MH  - Erythrocytes/*drug effects/metabolism/*pathology
MH  - Female
MH  - Guanine Nucleotides/*blood
MH  - Humans
MH  - Immune System Diseases/blood/drug therapy
MH  - Immunosuppressive Agents/blood/pharmacokinetics/*therapeutic use
MH  - Lupus Erythematosus, Systemic/blood/drug therapy
MH  - Male
MH  - Middle Aged
MH  - Still's Disease, Adult-Onset/blood/drug therapy
MH  - Thionucleotides/*blood
EDAT- 2000/03/11 09:00
MHDA- 2000/03/25 09:00
CRDT- 2000/03/11 09:00
PHST- 2000/03/11 09:00 [pubmed]
PHST- 2000/03/25 09:00 [medline]
PHST- 2000/03/11 09:00 [entrez]
AID - S0022-2143(00)82715-8 [pii]
AID - 10.1067/mlc.2000.105215 [doi]
PST - ppublish
SO  - J Lab Clin Med. 2000 Mar;135(3):256-62. doi: 10.1067/mlc.2000.105215.