Paracetamol Effect on Oxidative Stress and Renal Function in Severe Malaria
Blackwater fever, characterized by intravascular haemolysis and hemoglobinuria, is an important cause of renal impairment and mortality in severe malaria caused by Plasmodium falciparum. The largest malaria clinical trials report blackwater incidences of 5-7% in Asian adults and 4% in African children with severe malaria treated with artesunate or quinine. The prevalence of blackwater fever in Chittagong, Bangladesh is 15% with associated rates of renal failure and mortality of 42.9% and 14.2% respectively.
The fundamental characteristic of blackwater fever is the presence of intravascular hemolysis of both infected and uninfected erythrocytes and release of free haemoglobin. The cytotoxic free haemoglobin present can cause severe oxidative damage as a result of haem redox cycling yielding ferric and ferryl heme, which generate radical species that induce lipid peroxidation and subsequent production of F2-isoprostanes (F2-IsoPs). Evidence suggests that F2-IsoPs generated by the hemoprotein-catalyzed oxidation of lipids are responsible for the oxidative damage and vasoconstriction associated with renal injury in haemolytic disorders and rhabdomyolysis.
A novel mechanism of paracetamol was recently demonstrated, showing that paracetamol is a potent inhibitor of hemoprotein-catalyzed lipid peroxidation by reducing ferryl heme to its less toxic ferric state and quenching globin radicals. In a recent proof of concept trial, paracetamol at therapeutic levels was shown to significantly decrease oxidant kidney injury, improve renal function and reduce renal damage by inhibiting the hemoprotein-catalyzed lipid peroxidation in a rat model of rhabdomyolysis-induced renal injury. Since adults with severe malaria demonstrate increased concentrations of cell-free haemoglobin, and urinary F2-IsoPs, the investigators hypothesize that this novel inhibitory mechanism of paracetamol may provide renal protection in this population by reducing the hemoprotein-induced lipid peroxidation. As there is currently no consensus that exists concerning adequate medical treatment for blackwater fever, the potential application of this safe and extensively used drug would be of great benefit.
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
|Official Title:||Paracetamol Effect on Oxidative Stress and Renal Function in Severe Falciparum Malaria With Intravascular Haemolysis: A Randomised Controlled Clinical Trial|
- Effect of paracetamol concentrations [ Time Frame: 72 hours ]Compare the effect of therapeutic paracetamol concentrations compared with absent or low paracetamol concentration on renal function, peak creatinine levels or trough creatinine clearance, defined as the change at 72 hours compared to baseline, in patients with severe and moderately severe falciparum malaria stratified by the level of intravascular haemolysis (cell-free haemoglobin).
- Compare treatment arm with control arm with respect to duration of Acute Kidney Injury (AKI) and development of AKI. [ Time Frame: 14 days ]Duration of AKI will be defined as the length of time elapsed until serum creatinine returns to normal (<1mg/dL) in the absence of renal replacement therapy. Development of AKI will be assessed using the Acute Kidney Injury Network (AKIN) criteria, and by a creatinine increase of >= 0.5mg/dl or 25%. Plasma paracetamol concentration will be measured daily by liquid chromatography-mass spectrometer (LC-MS/MS).
- Compare between groups correlations between oxidative stress, cell-free hemoglobin and renal function [ Time Frame: 3 days ]Urine and plasma F2-isoprostanes and isofurans will be measured by gas chromatography-mass spectrometry. Cell-free haemoglobin measured as plasma concentration by enzyme linked immunosorbent assay (ELISA) on admission then daily for 72hours. Cell free haem measured in plasma using a chromogenic assay on admission then daily for 72hours. Haem-to-protein cross-links measured by high performance liquid chromatography (HPLC) on admission and daily for 72hours.
- Assessment of Blackwater fever and association with renal function [ Time Frame: 7 days ]Blackwater fever assessed using a standardized urine colour chart and urine haemoglobin every 6 hours until clinical recovery between groups.
- Mortality and hemodialysis trends [ Time Frame: 4 weeks ]To compare mortality and hemodialysis trends between groups and evaluate if they correlate with level of oxidative stress, cell free haemoglobin and renal function.
- Host factors of Intravascular Haemolysis [ Time Frame: 4 weeks ]Intravascular haemolysis according to G6PD status.
- Fever clearance time [ Time Frame: 7 days ]Compared fever clearance time defined as the time taken for the tympanic temperature to fall below 37.5°C and remain there for at least 24hours); Fever time defined as the duration in hours of an individuals temperature above 37.5°C; Area above the 37.5°C temperature versus time curve (AUC-T°) within first 24hours of treatment. Aural temperature will be measured every 6 hours until fever clearance.
- Parasite clearance time [ Time Frame: 7 days ]Parasite clearance time assessed by microscopy of peripheral blood films will be assessed every 6hours for the presence of asexual parasitaemia until negative on 2 consecutive blood films. Parasite half lives and clearance time will be compared between groups. Parasites will also be staged to assess if sequestration is inhibited due to temperature reduction.
- Parasite sequestration [ Time Frame: 7 days ]Parasite sequestration assessed by capillary flow in the rectal microcirculation using Orthogonal Polarization Spectral (OPS) imaging will be compared between groups.
- Assessment of Acute Kidney Injury [ Time Frame: 7 days ]Evaluation of pre-renal and acute tubular necrosis assessed by blood and urine biomarkers of pre-renal and renal injury including neutrophil gelatinase-associated lipocalcin (NGAL) and kidney injury molecule (KIM).
- Urine scoring of dehydration and haemolysis [ Time Frame: 72 hours ]Urine colour will be assessed by standardized urine colour charts. Urine colour will be correlated with urine specific gravity, urine osmolality, urine haemoglobin and creatinine clearance.
- Safety assessment [ Time Frame: 6 weeks ]Safety assessed by the number of patients with serious adverse events (SAEs) and by changes from baseline in vital signs and laboratory measurements.
- Assess the antimalarial drug sensitivity of patients treated with paracetamol [ Time Frame: 72 hours ]Preliminary in vitro studies suggest that paracetamol potentiates the anti-parasitic effect of artesunate as lower 50% inhibitory concentration of artesunate is observed when paracetamol is added to parasites in culture. We will investigate whether this effect is dependent on the infecting P. falciparum parasite strain
- Paracetamol pharmacokinetics [ Time Frame: 72 hours ]Pharmacokinetic modelling of oral paracetamol in severe and moderately severe malaria
- Paracetamol pharmacodynamics [ Time Frame: 72 hours ]Pharmacodynamics on variables including temperature and parasitemia.
- Area under the plasma concentration versus time curve (AUC) [ Time Frame: 72 hours ]for paracetamol
- The maximum concentration (Cmax) [ Time Frame: 72 hours ]for paracetamol
|Study Start Date:||July 2012|
|Estimated Study Completion Date:||December 2017|
|Estimated Primary Completion Date:||December 2016 (Final data collection date for primary outcome measure)|
>50kg: Paracetamol 1gm PO/NG q6hourly for 72 hours and febrile for 24 hours (maximum total dose 4g/24 hours) plus intravenous Artesunate
<50kg: Paracetamol 12.5-15mg/kg/dose q6hourly for 72 hours and febrile for 24 hours (maximum total dose 5 doses/24hours;75mg/kg) plus intravenous Artesunate
>50kg: Paracetamol 1gm PO/NG q6hourly for 72hours and afebrile for 24h (maximum total dose 4g/24 hours) plus intravenous Artesunate <50kg: Paracetamol 12.5-15mg/kg/dose q6hourly for 72hours and afebrile for 24h (maximum total dose 5 doses/24hours;75mg/kg) plus intravenous Artesunate
Active Comparator: No Paracetamol
No paracetamol + Intravenous Artesunate
Drug: No Paracetamol
No paracetamol + Intravenous Artesunate
Show Detailed Description
Please refer to this study by its ClinicalTrials.gov identifier: NCT01641289
|Chittagong Medical College Hospital|
|Ramu Upazilla Health Complex|
|Principal Investigator:||Katherine Plewes, MD||University of Oxford|