Abstract

Background

The objective of this study was to profile the user acceptability (self-reported adverse effects and compliance patterns) for mefloquine (250 mg weekly) and doxycycline (100 mg daily), which are currently the recommended malaria chemoprophylactic regimens for chloroquine resistant areas.

Methods

Travelers with return dates between November 1993 and October 1994 were enrolled in the study at a pretravel consultation at the Traveller's Medical and Vaccination Centres (TMVC) clinics in Adelaide and Melbourne, if they had been prescribed either mefloquine or doxycycline as the sole chemoprophylactic for their trip. The choice of antimalarial was decided after intensive discussions of the two regimens, contraindications, potential side effects, relative costs, and preferred efficacy. Questionnaires relating to self-reported morbidity and compliance levels were mailed to travelers approximately 2 weeks after their return to Australia.

Results

Two hundred and eighty-five travelers (60.0% female, 40.0% male) used mefloquine for a mean of 6.5 tablets. Overall, 51.2% of users experienced illness or symptoms while taking the medication. Symptoms attributed by travelers to mefloquine, and usually temporally related to it, were reported by 37.9% of all users. Adverse events with significant impact on activities were reported by 14.6% of all female users and 6.1% of all male users. On return, 78.2% reported complete compliance with the mefloquine regimen overall; 6.3% stopped the drug specifically because of adverse effects, which were attributed to the drug and which were interfering with daily activities (8.8% females and 2.6% males).

Three hundred and eighty-three travelers (47.8% female and 52.2% male) used doxycycline for a mean of 27.5 daily doses. Health problems were experienced by 36.8% of travelers and 21.4% overall experienced what they considered to be adverse drug effects. Troublesome effects were reported by 8.7% of all females and 4.5% males. Complete compliance with the regimen was reported by 68.1% of users. Overall, 5.7% stopped early because of adverse effects, which were attributed to the drug and which were interfering with daily activities (6.6% females, 5.0% males).

Conclusions

Drug morbidity must be a consideration when prescribing antimalarial drugs. Noted in this study was the finding of a greater number of adverse events reported by females, particularly for mefloquine. The reasons for this difference between males and females will need to be further explored.

References

1
World Health Organization.
Malaria chemoprophylaxis regimens for travellers
.
Wkly Epidemiol Rec
 
1993
;
51
:
377
383
.
2
NHMRC.
Report of the NHMRC Public Health Committee: Malaria Prophylaxis
. Canberra :
Australian Government Publishing Service
,
1993
.
3
Kando
JC
Yonkers
KA
Cole
JO.
Gender as a risk factor for adverse events to medications
.
Drugs
 
1995
;
50
:
1
6
.
4
Phillips
M.
Antimalarial mefloquine. (Letter to the Editor.)
Med J Aust
 
1994
;
161
:
227
.
5
Steffen
R
Fuchs
E
Schildknecht
J
, et al.
Mefloquine compared with other malaria chemoprophylactic regimens in tourists visiting East Africa
.
Lancet
 
1993
;
341
:
1299
1305
.
6
Fine
PEM
Chen
RT.
Confounding in studies of adverse reactions to vaccines
.
Am J Epidemiol
 
1992
;
136
:
121
135
.
7
Davies
DM.
Textbook of adverse drug reactions
.
4th Ed
. Oxford :
Oxford University Press
,
1991
.
8
Macleod
SM
Giles
HG
Bengert
B
, et al.
Age and gender related differences in diazepam pharmacokinetics
.
J Clin Pharmac
 
1979
;
19
:
15
19
.
9
Hunt
CM
Westerkam
WR
Stave
GM.
Effect of age and gender on the activity of human hepatic CYP3A
.
Biochem Pharmacol
 
1992
;
44
:
275
283
.
10
Karbwang
J
Bunnag
D
Breckenridge
AM
, et al.
The pharmacokinetics of mefloquine when given alone or in combination with sulphadoxine and pyrimethamine in Thai male and female subjects
.
Eur J Clin Pharmacol
 
1987
;
32
:
173
177
.
11
Wittes
RC
Saginur
R.
Adverse reaction to mefloquine associated with ethanol ingestion
.
Can Med Assoc J
 
1995
;
152
:
515
517
.
12
Lobel
HO
Miani
M
Eng
T
, et al.
Long-term malaria prophylaxis with weekly mefloquine
.
Lancet
 
1993
;
341
:
848
885
.
13
Behrens
RH
Roberts
JA.
Is travel prophylaxis worthwhile? Economic appraisal of prophylactic measures against malaria, hepatitis A, and typhoid in travellers
.
BMJ
 
1994
;
309
:
918
922
.
Paper presented at the Fourth International Conference on Travel Medicine, Acapulco, Mexico, April 23–27, 1995.
Research sponsored by Roche and Pfizer Pharmaceuticals.