Drug Absorption

Drug
Absorption

   

• P.J.A.
  Yeates & S.H.L. Thomas (Wolfson Unit of Clinical
  Pharmacology, University of Newcastle, UK)
  
  Effectiveness
  of delayed activated charcoal administration in
  simulated paracetamol (acetaminophen) overdose.
  
  Br.J.Clin
  Pharmacol, 49, 11-14.
  
    
  
  Summary
  : Oral activated charcoal is used to treat drug
  overdose and is effective at reducing drug
  absorption when given within 1 hour of drug
  ingestion. In
  most cases of drug overdose, the delay in
  administering activated charcoal is more than 1
  hour. This study has investigated the efficacy of activated charcoal at
  preventing paracetamol absorption after simulated
  overdose (3 gms. Paracetamol tablets in healthy
  volunteers) when administration was delayed between
  1 and 4 hours. Dose
  of activated charcoal used was 50 gms.
  Plasma paracetamol concentrations were
  measured using HPLC.
  
    
  
  Activated
  charcoal significantly reduced paracetamol AUC (4,9
  hrs) when administered after 1 hr, but
  administration after 2 or 4 hrs did not have
  significant effect. Results
  in healthy volunteers cannot be directly
  extrapolated to patients of overdose, but they
  provide no evidence of efficacy for activated
  charcoal when administered after an interval of more
  than 2 hrs.
  
    
  

• Henrik
  Toft Sorensen, Gunnar Lauge Nielsen, et al
  (Department of 
  Internal Medicine V, 
  Aarhus University Hospital Aarhus, Denmark)
  
  Birth
  outcome following maternal use of metoclopramide
  
  Br.J.Clin.Pharmacol,
  49, 264-268.
  
    
  
  Summary:
  Metoclopramide is an antiemetic drug used widely
  during pregnancy for nausea and vomiting.
  As its use is widespread, adverse effects on
  infants would have major public health implications.
  
    
  
  This
  study has been conducted in Sweden, using the
  Pharmaco-Epidemiological Prescription Database.
  Three hundred and nine women who had
  prescriptions for metoclopramide from January to
  December 1996 were included in the study.
  Information on malformations, birth-weight,
  preterm deliveries and stillbirths were compared
  with controls (13,327 women) who did not receive
  prescriptions of any kind during pregnancy.
  
    
  
  The
  authors could not document any association between
  the use of metoclopramide during pregnancy and
  adverse pregnancy outcome.
  As this is limited study, further research is
  required.
  
    
  

• Jean
  Frederic Westphal (Unit
  of Geriatric Medicine, France)
  
  Macrolide
  – induced clinically relevant drug interactions with
  cytochrome P-450a
  (cyp)
  3A4: an update focused on clarithromycin,
  azithromycin and dirithromycin.
  
  Br.
  Jr.Cl. Pharmacology, oct.2000, 50(4), 285-295
  
    
  
  Summary: Erythromycin binds strongly,
  clarithromycin to a lesser extent and azithromycin
  the least to the cytochrome CYP 3A4, which is
  involved in oxidative phase of biotransformation of
  drugs. Hence,
  erythromycin produces maximum drug interactions and
  azithromycin and dirithromycin the least drug
  interactions.
  
     
  
  Clinically
  relevant drug-interactions with benzodiazepines,
  neuroleptics, HMG CoA reductase inhibitors,
  anti-arrhythmic agents and warfarin are described.