The most commonly reported adverse events occurring more frequently in lansoprazole treated patients compared to placebo include abdominal pain, constipation, diarrhea, and nausea.FDA Label There is a case report of toxic epidermal necrolysis (TEN), which is a rare but very serious cutaneous reaction, caused by lansoprazole.^A177190 The previously healthy patient presented with symptoms of TEN 15 days after starting lansoprazole to manage peptic disease.^A177190 Although the use of PPI's is rarely associated with TEN, causation should be considered if a patient presents with TEN shortly after newly commencing a PPI.^A177190

In a single case report, a patient ingested 600 mg of lansoprazole and did not experience any adverse effects or symptoms of overdose.FDA Label Overall, lansoprazole is well tolerated with relatively few adverse effects.

Lansoprazole is classified as Pregnancy Category B.FDA Label Although there are animal studies that suggest lansoprazole does not cause harm to the fetus, there is still a paucity of human data. Hence, lansoprazole should only be administered to pregnant women if other options with more safety data have been exhausted.

It is unknown if lansoprazole is excreted in human breast milk.FDA Label It is worth mentioning that lansoprazole has been used safely in infants, and is therefore likely safe to use during breastfeeding.^L6340