PMID- 25643810
OWN - NLM
STAT- MEDLINE
DCOM- 20151123
LR  - 20181113
IS  - 1179-1918 (Electronic)
IS  - 1173-2563 (Linking)
VI  - 35
IP  - 3
DP  - 2015 Mar
TI  - Drug interactions with levothyroxine therapy in patients with hypothyroidism: 
      observational study in general practice.
PG  - 187-95
LID - 10.1007/s40261-015-0271-0 [doi]
AB  - BACKGROUND AND OBJECTIVES: Several drugs may interact with levothyroxine and 
      reduce its bioavailability. The aim of this study was to analyse the Italian 
      general practice patients with hypothyroidism from 2002-2011, in terms of 
      variation of thyroid-stimulating hormone (TSH) levels, number of levothyroxine 
      prescriptions and dose of levothyroxine before and during potential drug-drug 
      interactions (DDIs). METHODS: Data were extracted from the Italian general 
      practice Health Search CSD Longitudinal Patient Database (HSD). Analysis was 
      limited to individuals aged 18 years and older with at least one levothyroxine 
      prescription from 2002 to 2011 and at least one year of clinical history recorded 
      in HSD. A quasi-experimental pre-post analysis was carried out using a 
      self-controlled study design, on an intention-to-treat basis. RESULTS: Overall, 
      5,426 levothyroxine users (7.5 % of population in HSD) were included in the 
      study. The incidence rate ratio comparing the TSH trend before and during the 
      period of exposure to potential DDI showed a significant increase of TSH levels 
      during initial exposure to potential DDI, which decreased over time. The number 
      of prescriptions and dose of levothyroxine decreased before the potential DDI and 
      increased symmetrically during the period of exposure to potential DDI. 
      CONCLUSIONS: The co-prescription of levothyroxine and potentially interacting 
      drugs results in an increased use of levothyroxine. Clinicians should carefully 
      consider adjusting levothyroxine therapy in presence of concomitant drugs, such 
      as proton-pump inhibitors, which may reduce levothyroxine bioavailability.
FAU - Trifiro, Gianluca
AU  - Trifiro G
AD  - Department of Clinical and Experimental Medicine, Pharmacology section, 
      University of Messina, Messina, Italy, g.trifiro@erasmusmc.nl.
FAU - Parrino, Fabrizio
AU  - Parrino F
FAU - Sultana, Janet
AU  - Sultana J
FAU - Giorgianni, Francesco
AU  - Giorgianni F
FAU - Ferrajolo, Carmen
AU  - Ferrajolo C
FAU - Bianchini, Elisa
AU  - Bianchini E
FAU - Medea, Gerardo
AU  - Medea G
FAU - Benvenga, Salvatore
AU  - Benvenga S
FAU - Cricelli, Iacopo
AU  - Cricelli I
FAU - Cricelli, Claudio
AU  - Cricelli C
FAU - Lapi, Francesco
AU  - Lapi F
LA  - eng
PT  - Journal Article
PT  - Observational Study
PL  - New Zealand
TA  - Clin Drug Investig
JT  - Clinical drug investigation
JID - 9504817
RN  - Q51BO43MG4 (Thyroxine)
SB  - IM
MH  - Drug Interactions
MH  - Female
MH  - General Practice
MH  - Humans
MH  - Hypothyroidism/*drug therapy
MH  - Male
MH  - Middle Aged
MH  - Multivariate Analysis
MH  - Thyroxine/*therapeutic use
EDAT- 2015/02/04 06:00
MHDA- 2015/12/15 06:00
CRDT- 2015/02/04 06:00
PHST- 2015/02/04 06:00 [entrez]
PHST- 2015/02/04 06:00 [pubmed]
PHST- 2015/12/15 06:00 [medline]
AID - 10.1007/s40261-015-0271-0 [doi]
PST - ppublish
SO  - Clin Drug Investig. 2015 Mar;35(3):187-95. doi: 10.1007/s40261-015-0271-0.