Possible Interaction: Doxycycline and Quinine

“Re-treatment with unsupervised quinine ± doxycycline resulted in further recurrence of malaria in 48% (95% CI 31–65) of P. falciparum infections and 70% (95% CI 37–100) of P. vivax infections.”

“ Doxycycline plus quinine should not be given to children under 12 years as doxycycline is contraindicated in this age group, but clindamycin can be substituted for doxycycline, and pyrimethamine-sulfadoxine (Fansidar) may also be an effective substitute.”

“Mefloquine and quinine both showed synergism of artesunate activity against each of the strains, whilst doxycycline showed an additive interaction.”

“ Quinine is highly effective but poorly-tolerated in prolonged treatment and should be used in combination with an additional drug, usually oral doxycycline.”

“This occurred after successful treatment with quinine plus doxycycline over seven days.”

“Decreased in vitro susceptibility to quinine and the delayed effect of doxycycline may both have contributed to the delayed parasite clearance time, D4 (0.5%) and D7 (0.004%).”

“When the plasma/serum concentrations possibly attained after their usual therapeutic doses were taken into account, tetracycline, doxycycline , omeprazole, ketoconazole, nifedipine, troleandomycin and erythromycin are likely to be inhibitors of quinine metabolism in patients when these drugs are co-administrated with quinine.”

“Among the antimalarial drugs, doxycycline showed relatively potent inhibition of quinine 3-hydroxylation with a mean IC50 value of 17 microM, followed by primaquine and tetracycline, with mean IC50 values of 20 and 29 microM, respectively.”

“It is interesting to note that two patients failed treatment with quinine alone but responded to the combination of quinine + oral doxycycline.”

“It is interesting to note that two patients failed treatment with quinine alone but responded to the combination of quinine + oral doxycycline.”