The respiratory depressant effects of narcotics and their capacity to elevate cerebrospinal fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions or a pre-existing increase in intracranial pressure. The concurrent use of anticholinergics with codeine may produce paralytic ileus. There are no studies in humans, and the significance of these findings to humans, if any, is not known. Acetaminophen with codeine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. These signs include irritability, excessive crying, tremors, hyperreflexia, fever, vomiting, and diarrhea.
Signs usually appear during the first few days of life.
Narcotic analgesics cross the placental barrier. The closer to delivery and the larger the dose used, the greater the possibility of respiratory depression in the newborn. Narcotic analgesics should be avoided during labor if delivery of a premature infant is anticipated. If the mother has received narcotic analgesics during labor, newborn infants should be observed closely for signs of respiratory depression. Acetaminophen with codeine is not recommended during lactation because safety in nursing mothers has not been established.