Reviewed by Esther How Huey Jiun

Many times, we found ourselves fumbling over resources when customers ask about safety of drugs in pregnancy. We do it more often now with the pandemic hitting the globe, but why are we still unsure which drug is safe for this category of patient? To smooth your journey amidst the covid waves, here is the summary for the most common medicines requested for pregnant ladies to stop you on the track of perfusing heavily whenever a customer asks you about safety of commonly dispensed medicines:

1. Pain & Fever

• The safest drug of choice is our old friend Paracetamol (Category C).¹ Avoid NSAIDS (don’t forget aspirin although it is the least dangerous of them all!) as some studies showed possible relationship between intake of NSAIDs with a higher rate of miscarriage.^2,3 What about opioids? Use codeine (Category C) with caution as it may result in respiratory depression as well as possible withdrawal syndrome in new-borns.^4,5 Caffeine (Category C) has shown adverse effects on foetus in animal studies if taken in dosage higher than 200mg and ergotamine (Category X) are contraindicated in pregnancy. ^{6- 9}

2. Cold & Flu; Allergic rhinitis

• All antihistamines are safe for pregnancy, however, there are more safety data related to the use of older generation antihistamines such as chlorpheniramine.¹⁰ With regards to blocked nose, unfortunately oral decongestants such as Phenylephrine (Category C) and pseudoephedrine are generally not safe, particularly in the first trimester.^11-13 On the other hand, intranasal decongestants are considerably safer if used for a very brief period of about 3 days.¹² It is safe to use corticosteroid nasal sprays.¹²

3. Cough

• Although it might sound scary, dextromethorphan (Category C), guaifenesin and pholcodine are considered safe in pregnancy (I too will triple check when I give opioids to pregnant ladies).^14-16 It is also safe to use bromhexine in pregnancy whereas carbocisteine has limited research data to warrant their uses.^17,18 N-acetylcysteine or NAC (Category B) should be used only when deemed necessary especially in cases of paracetamol poisoning.^19,20 Diphenhydramine and ammonium chlorides (Category A) are considerably safe to use.^21,22 Ambroxol maybe safer than carbocisteine and NAC but avoid its use in the first trimester.²³

4. Sore throat

• Most medicated lozenges have insufficient data to prove that they are safe for pregnancy.^24,25 In this case, I will opt for honey lozenges with Unique Manuka Number (UMF) or Methylglyoxal (MGO) stated on their boxes, but care was to be taken when dispensing these lozenges to pregnant ladies with gestational diabetes. Throat gargle with antibacterial and anti-inflammatory properties may be a good option also. The manufacturer discourages the use of lysozyme, aescin, serratiopeptidase and papain in pregnancy due to the lack of safety data.^26-31

5. Nausea & Vomiting

• Metoclopramide (Category B) is safe to use but never dispense domperidone (Category B2).^32-34 Certain antihistamines such as dimenhydrinate (Category B) have more clinical studies on pregnant ladies so they are considerably safe to use also.^35,36 Promethazine (Category C) and Prochlorperazine are generally safe in early pregnancy but avoid close to delivery due to theoretical risk of neurological disturbance in infant.^35,37,38

6. Diarrhoea

• Loperamide(Category C) may be safe for one or two times use.^8,39,40 Avoid diphenoxylate and atropine closer to term (Category C).^41,42 Here we may consider charcoal.⁴³ There isn’t much clinical research data to back up the use of dioctahedral smectite and racecadotril in pregnancy.^44,45 It is safe to use hyoscine butylbromide for stomach cramps but there is no data available to warrant the use of mebeverine in pregnancy.^46,47

7. Constipation

• This is a very common problem amongst the pregnant women. Aside from the usual fluid and fiber, Lactulose (Category B) is the first drug of choice as it remains in the gastrointestinal tract after ingestion.^8,48 Avoid senna (Category C) or other stimulant laxatives such as bisacodyl (Category C) if possible.^49,50

8. Dizziness / motion sickness

• The combination of meclozine (Category B) and pyridoxine (Category A) – in another name, vitamin B6 is going to be your best choice here.^51,52 Cinnarizine and betahistine both have limited data, so they are not preferable in this category of patient. ^53,54

9. Gastric reflux

• All H2 receptor antagonists aregenerally safe to use. Cimetidine (Category B) have more safety data than Famotidine (Category B).^55-57 Omeprazole (Category C) has more clinical research on pregnancy compared to other proton pump inhibitors.^58,59  Antacids may be considered if they does not contain sodium bicarbonate or magnesium trisilicate.⁵⁷

10. Skin irritation

• If needed, use low or moderate potency topical corticosteroids.¹²Use of potent or superpotent corticosteroids in the 3^rd trimester may result in low birth weight.¹² If needed, use sparingly for the shortest duration possible.¹² Maintainance on moisturisers and/or calamine will be desirable.¹²

Now you can keep your cool when you encounter enquiries about safety of medicine in pregnancy!

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2. Australian Medicines Handbook 2020 (online). Adelaide: Australian Medicines Handbook Pty Ltd; 2020 July. NSAIDs; [updated 2022 Jan; cited 2022 Jun 26].Available from: https://amhonline.amh.net.au/
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4. MIMS Online [Internet].Petaling Jaya: MIMS Malaysia; 2010. Codeine [cited 2022 June 15]. Available from: https://www.mims.com/malaysia/drug/info/codeine?mtype=generic
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The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice should consult with a licensed physician. Always seek the advice of your doctor or other qualified health provider regarding a medical condition.