Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Significant naproxen overdosage may be characterized by drowsiness, heartburn, indigestion, nausea
or vomiting. In the event that ANAPROX/ANAPROX-DS, ALEVE, or naproxen sodium is taken with
Lansoprazole , earlier and higher blood levels may be anticipated due
to the rapid absorption of naproxen sodium. A few patients have experienced seizures, but it is not
clear whether or not these were drug-related. It is not known what dose of the drug would be lifethreatening. Return to top
The oral LD50 of the drug is 543 mg/kg in rats, 1234 mg/kg in mice, 4110 mg/kg in
hamsters, and greater than 1000 mg/kg in dogs.
Should a patient ingest a large number of tablets, accidentally or purposefully, the stomach may
be emptied and usual supportive measures employed. In animals 0.5 g/kg of activated charcoal was
effective in reducing plasma levels of naproxen. Hemodialysis does not decrease the plasma
concentration of naproxen because of the high degree of its protein binding. Return to top
Oral doses up to 5000 mg/kg in rats (approximately 1300 times the 30 mg human dose based on body
surface area) and mice (about 675.7 times the 30 mg human dose based on body surface area) did not
produce deaths or any clinical signs.
LANSOPRAZOLE IS NOT REMOVED FROM THE CIRCULATION BY HEMODIALYSIS. IN ONE
REPORTED CASE OF OVERDOSE, THE PATIENT CONSUMED 600 MG OF LANSOPRAZOLE WITH NO
ADVERSE REACTION. Return to top
Adapted from the FDA Package Insert.