Chinedum B Babalola , Titilayo T Fashedemi, Ajibola A Olaniyi

For correspondence:-  Chinedum Babalola   Email: peacebab2001@yahoo.com

Published: 20 June 2003

Citation: Babalola CB, Fashedemi TT, Olaniyi AA. Chloroquine reduces urinary excretion of cloxacillin when it is administered concurrently with ampicillincloxacillin combination. Trop J Pharm Res 2003; 2(1):169-173 doi: 10.4314/tjpr.v2i1.7

© 2003 The authors.
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Abstract

Purpose:  To  investigate a possible effect  of  chloroquine on  urinary  excretion of  cloxacillin when chloroquine is administered concurrently with ampicillin-cloxacillin combination.

Methods:  Eight  healthy  adult  volunteers  received  single oral  doses  of  Ampiclox ® (ampicillincloxacillin  combination)  alone and  in  combination  with  chloroquine  in a  cross-over  study design  with one  week  washout  period between  the drug administrations.  Total  urine  voided was collected  from  each  volunteer  at  predetermined  time  intervals  for  a period of  9 hr.  The urine was analyzed for cloxacillin by a reversed-phase HPLC method.
Results:  A  significant  reduction  in  the amount  of  cloxacillin excreted  in urine  was  observed following  the  co-administration of  chloroquine and  the ampicillin-cloxacillin  combination products.  The mean total  amount  of  cloxacillin (Du ¥ ), maximum peak of  excretion (Du max) and % dose excreted after  Ampliclox ® was  administered alone  were 84.6  ±  57.0  mg,  49.5  ±41.6 mg and 33.9  ±  22.7%  respectively.  The  corresponding  values  after  co-administration  with chloroquine were 30.2 ±  27.2 mg,  13.5 ±  10.4 mg and 12.1 ±10.9%.    The respective times of maximum  absorption  (Tmax)  and elimination half-life  (t1/2)  of  cloxacillin  were  2.7  ±  0.4 hr  and 0.7 ±  0.4 hr  after  Ampiclox ® alone and 1.5 ±  0.8 hr  and 0.6 ±  0.5 hr  after  co-administration of the  two drugs.  The  results showed a  significant  decrease  (p  <  0.0001)  in  the  mean  total amount  as  well  as  % dose of  cloxacillin excreted  in urine by  64% and a  significant  reduction (p < 0.05) in the Tmax of excretion by 45%.
Conclusion:  There  is  appreciable  reduction  in  the urinary  excretion of  cloxacillin when given concurrently  with  chloroquine.  The  mode of this  interaction and  possible  therapeutic implication  is  unknown.  However,  caution  should be exercised  when prescribing or administering these two drugs together.