Are Benadryl (diphenhydramine), potassium chloride, magnesium oxide, and intravenous (IV) Tylenol (acetaminophen) safe to use at 28 weeks of gestation?

From the Guidelines

The use of Benadryl, potassium chloride, magnesium oxide, and IV Tylenol at 28 weeks of gestation should be approached with caution, considering the potential benefits and risks, and ideally under the guidance of an obstetrician or maternal-fetal medicine specialist. During pregnancy at 28 weeks gestation, medication safety varies among the drugs mentioned. Benadryl (diphenhydramine) is generally considered safe during pregnancy, including the third trimester, and is often used for allergies, sleep issues, or nausea. Intravenous Tylenol (acetaminophen) is also typically considered safe when medically necessary, though it should be used at the lowest effective dose for the shortest duration needed, as some studies have reported an association between prenatal acetaminophen use and potential increased risk for adverse neurological outcomes in childhood 1. Potassium chloride supplements are safe when prescribed for documented potassium deficiency, but should only be taken under medical supervision as improper dosing can be harmful. Magnesium oxide may be used for constipation or magnesium supplementation during pregnancy, but should be taken as directed by a healthcare provider.

Key considerations for the use of these medications during pregnancy include:

• The potential benefits of the medication outweighing the risks
• The use of the lowest effective dose for the shortest duration necessary
• Consultation with an obstetrician or maternal-fetal medicine specialist before initiating any medication
• Monitoring for any potential adverse effects on the mother or the developing fetus
• Awareness of the long history of use of these medications during pregnancy without evidence of significant harm, but also recognizing that no medication can be guaranteed completely risk-free during pregnancy, as noted in studies such as 1 and 1.

From the FDA Drug Label

8 USE IN SPECIFIC POPULATIONS

Risk Summary Published epidemiological studies with oral acetaminophen use during pregnancy have not reported a clear association with acetaminophen use and birth defects, miscarriage, or adverse maternal or fetal outcomes [see Data]. Animal reproduction studies have not been conducted with IV acetaminophen Reproductive and developmental studies in rats and mice from the published literature identified adverse events at clinically relevant doses with acetaminophen.

The FDA drug label does not answer the question about the safety of using Benadryl (diphenhydramine), potassium chloride, magnesium oxide, and intravenous (IV) Tylenol (acetaminophen) at 28 weeks of gestation, as it only provides information about acetaminophen.

From the Research

Medication Safety at 28 Weeks Gestation

• The safety of using Benadryl (diphenhydramine), potassium chloride, magnesium oxide, and intravenous (IV) Tylenol (acetaminophen) at 28 weeks of gestation is a concern due to the potential effects on the fetus.
• There is limited information available on the use of these medications together during pregnancy, particularly at 28 weeks gestation.
• A study published in 2008 2 investigated the use of acetaminophen and diphenhydramine as pretransfusion medications to prevent transfusion reactions, but it did not specifically address the safety of these medications during pregnancy.
• The study found that pretransfusion medication with acetaminophen and diphenhydramine did not decrease the overall risk of transfusion reactions, but it may decrease the risk of febrile nonhemolytic transfusion reactions to leukoreduced blood products.
• However, this study did not provide information on the safety of these medications during pregnancy, and its findings may not be directly applicable to the use of these medications at 28 weeks gestation.

Specific Medication Safety

• Benadryl (diphenhydramine) is a category B medication, which means that animal studies have not demonstrated a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women 2.
• Potassium chloride and magnesium oxide are essential minerals, but their use during pregnancy should be monitored closely to avoid any potential adverse effects on the fetus.
• IV Tylenol (acetaminophen) is commonly used for pain management during pregnancy, but its use should be limited to the lowest effective dose and for the shortest duration necessary.

Conclusion Not Applicable

References Not Applicable

Instead, more research is needed to determine the safety of using Benadryl, potassium chloride, magnesium oxide, and IV Tylenol at 28 weeks gestation. It is essential to consult with a healthcare provider to discuss the potential risks and benefits of using these medications during pregnancy.