What Should I Know About Common Morning Sickness Medications?

Morning sickness can severely impact your life during the first trimester of your pregnancy. For some women, persistent nausea, vomiting, headaches and general malaise are enough to prevent them from even leaving the house. If you’re on the hunt for morning sickness solutions that can help you function normally during your first trimester, the following medications may be of use.


Phenergan, also known as promethazine, is commonly prescribed for nausea associated with motion sickness and morning sickness. The drug also works well for sleep difficulties and allergic reactions because it blocks the release of endogenous inflammatory chemicals known as histamines. Its nausea-reducing capabilities stem from its ability to block the action of another endogenous chemical, acetylcholine. As Phenergan blocks acetylcholine, it reduces your body’s parasympathetic nerve impulses. Because nausea and vomiting are both regulated by your parasympathetic nervous system, promethazine works to calm the vomiting impulse. While the drug is certainly effective against morning sickness, it does carry side effects. They include:

  • Confusion

  • Altered heart rate

  • Photosensitivity

  • Sedation

  • Blurred vision

Keep in mind the above side effects are not an exhaustive list. Always do your research before ingesting any drug, even if it is prescribed by your physician. You’ll also need to inform your doctor of any other medications you are currently taking as Phenergan has certain drug interactions that may be dangerous for pregnant women. There is also a possibility that Phenergan use during late pregnancy may increase your baby’s risk of developing respiratory depression.


Zofran, also known as ondansetron, is commonly prescribed for the treatment of post-surgical nausea and vomiting as well as for similar symptoms associated with pregnancy. The drug works by blocking one of the body’s endogenous chemicals known as serotonin. Serotonin regulates your parasympathetic nerve impulses; because Zofran is a serotonin inhibitor, the drug works to prevent nausea and vomiting. Common side effects from the use of Zofran include:

  • Drowsiness

  • Dizziness

  • Headaches

  • Constipation

  • Lightheadedness

Uncommon, yet severe, Zofran side effects include muscle spasms, blurred vision, stomach discomfort and chest pain. If you experience any potentially severe side effects, contact your doctor immediately. Before using this drug, keep in mind that some fetuses have had in their own blood 50% of the levels of Zofran found in the mother, which has caused concerning problems in some cases. While using this drug, speak with your doctor about any worries you may have regarding your own health or that of your baby.


Diclegis contains a combination of pyridoxine (vitamin B6), and the antihistamine, doxylamine. The medication works by affecting the release of two endogenous chemicals, serotonin and acetylcholine. Because these chemicals regulate your body’s vomiting impulse, Diclegis works to calm nausea and reduce the urge to vomit. Common side effects when using Diclegis include:

  • Diarrhea

  • Constipation

  • Headache

  • Drowsiness

  • Difficulty sleeping

Serious, yet uncommon, side effects include irritability, confusion, anxiety, rapid heartbeat and urinary trouble. If you experience any alarming side effects, inform your doctor immediately. Diclegis does have several drug interactions, so be sure to inform your physician of any other medications you are currently taking. Keep in mind that Diclegis, formerly known as Bendectin, was pulled from the market in 1983 following reports of alleged birth defects. The medication was reapproved by the FDA in 2013 following numerous safety studies which confirmed no risk of fetal side effects.

Morning sickness can be a tough pill to swallow, but thankfully, there are several prescription pills designed to help you overcome it. Before taking any medication, always speak with your doctor regarding your own health concerns and those of your developing fetus. Anything you ingest can affect your baby, so always be cautious when it comes to medications!

Morning sickness is a small price to pay for your wonderful bundle of joy. Book a newborn session today to preserve those precious first weeks forever.