Morning sickness medication – is it safe?

We live in a very litigious society in Australia, now approaching a level not far beneath the USA.

It won’t surprise many to hear that Obstetricians are sued almost more than ANY other medical specialty.

Given that, do you think that any OBGYN in their right mind would give a patient a script for a medication to sue for morning sickness that they believed would harm them or their unborn baby?  Of course not.

And yet patients still certainly do worry unnecessarily about prescribed medications.  To an extent which often baffles me.

I have no doubt that much of this angst and worry is driven by the internet, with patient-driven searches on medication usage in pregnancy yielding uninformed, inflammatory and frequently completely WRONG results.  And yet these results are commonly believed before the doctor.  Go figure.

Before patients reach for medication, there are other steps they can take to help alleviate symptoms of morning sickness.  The cornerstone of non-pharmacologic therapy is the avoidance of so-called ‘environmental triggers’ – things that may bring nausea and vomiting on.  Examples of these include:

  • Odors including perfumes, food, smoke, chemicals.
  • Stuffy rooms, heat and humidity.
  • Visual or physical motion e.g. driving or strobing or flickering lights.
  • Teeth brushing
  • Use of some supplements.

Patients are also often well served by making dietary modifications.  Different things work for different patients,  but some suggestions include:

  • Eat before or as soon as hungry so as to avoid an empty stomach (which for some people can trigger nausea).
  • Eating frequent and smaller meals, which are high in carbohydrates and low in fats.
  • Eliminating or reducing consumption of spicy foods, or salty or high protein foods.

If none of these methods are working though, there’s no need for you to continue to suffer. There are a number of medications available to reduce morning sickness, all of which are safe during pregnancy. 


We don’t’ really know how or why ginger works – but we do know that it does have some efficacy.  A 2014 systematic review of all available and relevant trial data on ginger’s use found that it does improve nausea when compared to placebo, however, it does not significantly reduce the amount of vomiting.

Women can consume ginger containing foods or drinks such as ginger ale drinks or ginger tea, or they can take specific ginger supplements.  There is a growing supply of such products now available.  Ginger is safe, and being a non-pharmacological product it does not require a safety rating.


Don’t let the fancy name fool you, this is just vitamin B6.  This is a safe, proven, and effective treatment for morning sickness.  It is, in fact, considered to be the starting point and first-line agent for morning sickness.

Pyridoxine improves mild to moderate nausea but doesn’t significantly reduce vomiting so it is most useful for women who are nauseas, but not necessarily emptying their stomachs.

The precise reason why it works is unknown, but generally speaking it is likely due to the fact that B6 is a necessary enzyme in the metabolism and breakdown of fats, carbohydrates and amino acids.

The dosage is usually 25-50mgs three to four times daily, up to a maximum of 200mgs over 24 hours.  It can be used alone as a single agent or in combination with Doxylamine Succinate (which follows).  This is also a non-pharmacological product so it does not require a safety rating.


You know those medications that you take when you have allergic reactions, or severe hay fever?  Yep, these are very useful for morning sickness as well.  And yep, they are safe (if used appropriately!).

This class of medication is called H1 receptor antagonists, and they work in two ways.  Firstly, they block histamine’s actions at its receptor, and secondly, they decrease stimulation on the brain’s vomiting centre.

The main anti-histamine for use in morning sickness is Doxylamine succinate (Restavit/Dozile).  It is very effective, and its efficacy is actually improved even further when it is used in combination with Pyridoxine.  A bit like the pharmaceutical version of Batman and Robin perhaps?  Like most antihistamines it can cause some sedation, so it is principally used at night with the anti-nausea effect lasting throughout the following day.  The sedating effect typically wanes pretty quickly with use.  The usual dose is 25mgs at night, but it can also be used during the day as well if patients can tolerate it.  This is safe to use in pregnancy.

Promethazine (Phenergan) is another anti-histamine that is effective and safe.  It is useful for women who do not respond to Pyridoxine and Doxylamine.  The dose is also 25mgs at night.  This is an Australian category C drug and is safe to use in pregnancy for this condition.


Also known as Maxalon, this medication is part of a class of medications called ‘dopamine antagonists’.   It works in part by helping to speed the movement of food products through the gastric system.

The recommended dosage is 10mgs orally (or intravenously or intramuscularly), three to four times a day.  Preferably it should be used 30 minutes prior to a meal to improve its effectiveness.  This is an Australian category A medication and is safe to use.


Otherwise known as Zofran, this is in a class of medications called ‘serotonin antagonists’.  This medication is a very powerful anti-nausea agent, and is typically used as a fallback option when other medications aren’t working well enough, or when women are having a particularly bad day and need to get something done and need extra help.  I often tell my patients that they should consider the battle against morning sickness to be exactly that – a battle.  I then remind them of the old expression “you don’t take a knife to a gun fight”, and tell them that Zofran is, in fact, a BAZOOKER.

Zofran can be swallowed as a tablet, or taken as a wafer, which dissolves under the tongue.  Its dosage is 4-8mg twice daily.  It’s an Australian category B1 medication, which means that there is animal trial data, which is reassuring regarding its safety in humans.  So yes, it is considered safe to use in pregnancy!


Pregnant women often have acid reflux, and this can contribute to and worsen hyperemesis.  Given this, it is logical that getting rid of reflux or heartburn will help alleviate morning sickness.  Antacids such as ranitidine (Zantac) help suppress stomach acid production and are safe to use in pregnancy, being an Australian category B1.  The dose is 150mgs orally twice daily, or a single 300mg dose.

The important thing to remember is to use the medications prescribed to you as your doctor has advised.

However, if the prescribed regimen is not enough to control morning sickness it is highly likely that the woman requires admission to hospital for more intensive therapy including intravenous fluids.