6. When You Are Pregnant
If possible, you should avoid using ibuprofen when you are pregnant. A study in Human Reproduction suggests that taking ibuprofen in the first trimester of pregnancy can affect the reproductive organs of a developing female fetus. Additionally, according to the package insert, you should refrain from taking ibuprofen in the third trimester of pregnancy. In the third trimester, ibuprofen can close the baby’s ductus arteriosus, a critical blood vessel that bypasses the lungs before birth. During labor and delivery, ibuprofen is associated with more prolonged labor and an increased risk of stillbirth.
5. When You Are Allergic to NSAIDs
If you are allergic to ibuprofen and other NSAIDs, taking these medicines may trigger an immune response that includes hives, rash, and difficulty breathing. If you suffer from hypersensitivity to aspirin, you may also react poorly to ibuprofen. The FDA warns against taking ibuprofen if taking this drug, aspirin, or other NSAIDs has caused asthma, itching, or rashes in the past. If you suffer from aspirin-induced asthma, ibuprofen may also trigger episodes of asthma.
4. When You Are Anemic
Anemia is a condition in which your blood lacks the appropriate number of red blood cells to carry oxygen to your organs and tissues. Excessive bleeding, lack of vitamin-rich nutrients, and blood disorders can cause this condition. In some rare cases, overuse of ibuprofen can trigger hemolytic anemia, a condition in which red blood cells are destroyed faster than they are manufactured. Ibuprofen may lead to anemia by causing gastrointestinal bleeding, or by a mechanism that scientists do not yet understand.