Drowsiness may occur as a side effect of taking ibuprofen, according to WebMD. While this symptom is not noted as serious, it is recommended a person contact a doctor if problems persist. Other possible side effects include nausea, vomiting, constipation, diarrhea and headaches.
Most people who take ibuprofen safely and within recommended guidelines experience no significant side effects, according to WebMD. "Unusual tiredness" is noted as one of the more serious side effects a person should report right away. Some people also experience allergic reactions to ibuprofen, which may include rashes; swelling of the tongue, throat or face; difficulty breathing; and extreme dizziness.