title: Effect of artesunate and mefloquine in combination on the Fridericia corrected QT intervals in Plasmodium falciparum infected adults from Thailand.
abstract: OBJECTIVE
  To ascertain whether mefloquine (MQ) produces electrocardiogram (ECG) changes that could be a risk for Torsades de Pointe (TdP), a potentially malignant, ventricular tachyarrhythmia.
  
  
  METHODS
  We measured the Fridericia corrected QT (QTcF) intervals on 12 lead ECGs on days (D) 0, 3, 7 in Plasmodium falciparum infected adults, treated with oral artesunate (AS) and MQ as a new fixed dose (n = 25) combination or loose tablets (n = 25) over 3 days. Target total doses were 12 mg/kg of AS and 24-25 mg/kg of MQ. MQ concentrations ([MQ]) were measured by HPLC.
  
  
  RESULTS
  All ECG intervals were similar between drug arms and were combined for analysis. Mean QTcF values were 389 (D0), 407 (D3) and 399 (D7) ms (Ps < 0.003 vs. D0); corresponding heart rates and [MQ]s were 83, 67 and 73 beats/minute (Ps ≤ 0.0003 vs. D0) and 0, 3095 and 1721 ng/ml. One male patient (loose arm) had a D3 QTcF 504 ms (D0 406 ms, D7 433 ms). In the modelling of QTcF and JTcF from D0 to D7, significant effects were observed individually for [MQ], temperature and heart rate (HR). The MQ AUC(0-∞) was not a significant factor. Using a manual descending, model building approach to select variables, the HR was the only significant variable (P = 0.001) over time in the model that best explained the changes in the QTcF and JTcF intervals.
  
  
  CONCLUSIONS
  In this small group of patients, slowing heart rates due to malaria resolution best explained the observed increases in the QTcF intervals.
authors.affiliation: Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Krudsood
authors.forename: S
authors.initials: S
authors.lastname: Looareesuwan
authors.forename: P
authors.initials: P
authors.lastname: Wilairatama
authors.forename: W
authors.initials: W
authors.lastname: Leowattana
authors.forename: N
authors.initials: N
authors.lastname: Tangpukdee
authors.forename: K
authors.initials: K
authors.lastname: Chalermrut
authors.forename: S
authors.initials: S
authors.lastname: Ramanathan
authors.forename: V
authors.initials: V
authors.lastname: Navaratnam
authors.forename: P
authors.initials: P
authors.lastname: Olliaro
authors.forename: M
authors.initials: M
authors.lastname: Vaillant
authors.forename: J R
authors.initials: JR
authors.lastname: Kiechel
authors.forename: W R J
authors.initials: WR
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000328:Adult; D000962:Antimalarials / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D037621:Artemisinins / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D000077332:Artesunate; D004338:Drug Combinations; D004359:Drug Therapy, Combination / Q000379:methods; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy*; D008297:Male; D015767:Mefloquine / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D008875:Middle Aged; D016171:Torsades de Pointes / Q000139:chemically induced*; D055815:Young Adult
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D004338:Drug Combinations; D000077332:Artesunate; D015767:Mefloquine