Information last updated: June 2023
The baseline risk of major birth defects in Canada is 3-5%. This means that 3-5 out of 100 babies born in the general population in Canada will be born with a major birth defect. There are also baseline risks for miscarriages (15-25 out of 100 pregnancies), prematurity and other outcomes. The information provided will summarize if taking this drug is likely to change these risks.
Summary: Approximately 1600 pregnancies with exposure to phenylephrine in first trimester of pregnancy were included in published studies. Based on these studies it is not expected that taking phenylephrine during pregnancy will cause more babies to be born with major birth defects than in the general population.
Phenylephrine can constrict blood vessels (make them narrower). It is not known if the effects of this constriction could decrease the blood flow to the placenta. For this reason, use for more than a few days should be avoided. Phenylephrine can also increase blood pressure, and therefore cautious use is advised.
This information about phenylephrine is of a general nature and about medical use and does not replace the medical care and advice of your healthcare provider. For questions on dose, timing, side effects, interactions, etc. please consult your healthcare provider. Additionally, please read the patient insert provided with your medication.
Although participants in the studies referenced below may have used phenylephrine in various combinations, the studies usually do not provide detailed information on drug combinations. This makes it challenging to comment on the safety of using this medication in combination with others during pregnancy or lactation.
Phenylephrine has many uses.
It is found in cough and cold medications that are taken by mouth (oral) or used as a nasal spray where it works as a decongestant to relieve stuffy nose/congestion. The FDA has recently conducted a scientific review that suggested oral phenylephrine may not be effective as a decongestant.
It is found in hemorrhoid products where it is used topically (on the skin), as an ointment or suppository, to relieve burning, and/or itching from hemorrhoids.
It is found in some eye drops used to dilate (widen) the pupil.
It is used in surgery to treat or prevent low blood pressure.
This drug information page will focus on the use of phenylephrine as a decongestant for cough and colds.
If the product you are using contains other active ingredients, please check our Exposures A to Z for available information on the ingredient(s).
For more information on treating cough and cold while pregnant or providing your breastmilk to an infant, please see Treating the Common Cold in Pregnancy and Lactation
Pronunciation
(fen il EF rin)
Please check back. We are in the process of reviewing if there is available information on the pre-pregnancy effects of phenylephrine.
There have been several studies reporting on over 1600 exposures to phenylephrine in the first trimester of pregnancy. The available information on use of phenylephrine in the first trimester does not suggest an increased risk for major birth defects above the baseline risk in the general population. An analysis(test) in one study suggested there may be an increased risk of a rare heart defect. However, due to the study design, this finding likely happened by chance and is unlikely to represent a real risk. Even if the findings were real, the chance of these birth defects occurring remains low (approximately 4 in 1000). No other studies, including much larger studies, found any increased risk of heart defects.
No published studies were found addressing miscarriages, prematurity, or other pregnancy outcomes with use of phenylephrine in pregnancy.
Please check back. We are in the process of reviewing if there is available information on the effects of paternal exposure to phenylephrine.
We did not find published studies on the effects of phenylephrine use in pregnancy on the newborn. We will update this section if studies become available.
If you are taking medications and you notice any new health concerns or symptoms in your nursing infant, please contact their health care provider. In case of emergency, please go to the emergency room or call 911.
People who are taking a medication or substance while providing their breastmilk to an infant need to know how much of the medication or substance is passing into their milk. One of the commonly used measurements to estimate this is the Relative Infant Dose (RID). The RID is estimated by comparing the dose of drug taken in by the infant through breastmilk to the dose that the nursing parent takes. Most medications with an RID of less than 10% are usually compatible with nursing a healthy infant. The RID does not need to be calculated for each person because most of the time it is expected to be similar to what has been found in research studies. We will provide the RID in the information below, when available.
There are no studies on phenylephrine while nursing.
Based on the properties of phenylephrine, it is expected to pass into breastmilk. However, as there are no studies on phenylephrine use while nursing, we cannot estimate how much will pass into breastmilk. There is some information that suggests that when phenylephrine is taken together with acetaminophen, the amount expected to pass into breastmilk may increase. In Canada most medications that contain phenylephrine also contain acetaminophen. Please click How to Find Active Ingredients to check active ingredients in medications.
Animal data shows that phenylephrine lowers milk supply. There are no human studies on milk supply. When choosing a medication to be taken by mouth it is suggested to prefer products that do not contain phenylephrine, especially in the first month of nursing or if you are concerned about your milk supply.
We do not expect that using a nasal spray or eye drops containing phenylephrine will affect milk supply or the nursing infant.
We did not find published studies on the effects of phenylephrine use in pregnancy on long-term child/adult health outcomes. We will update this section if studies become available.
Costs of some medications are covered for eligible people under provincial or national Indigenous drug benefit plans. Please visit the Ontario Drug Benefit (ODB) program Check medication coverage or the Non-Insured Health Benefits (NIHB) program Drug Benefit List to check if phenylephrine is covered for you.
Medications, if not taken as prescribed, if taken beyond the prescribed amount, or if taken in combination with certain other drugs, may cause harm to you and/or your pregnancy or your nursing child.
If you are using drugs or medications for non-medical reasons or beyond what was recommended by your healthcare practitioner and you are pregnant, providing your breast milk to an infant, or parenting please click here Harm Reduction for additional information. In case of emergency, please go to the emergency room or call 911.
Pregnancy:
Over 1600 pregnancies with exposure to phenylephrine in the first trimester were included in published studies. Based on the available information, the use of phenylephrine during pregnancy is not expected to increase the risk for major birth defects above the baseline risk.
Phenylephrine produces systemic arterial vasoconstriction. It is not known if the effects of this vasoconstriction could decrease the blood flow to the placenta in humans; it has been shown to do so in animal models. For this reason, regular use should be avoided. Phenylephrine may increase blood pressure therefore caution is advised.
Based on the available information no increased risk of major malformations is expected following phenylephrine exposure in early pregnancy. One of the analyses in one of the studies suggested there may be an increased risk for endocardial cushion defect (aOR 8.0, 95% CI:2.5-25.3; 4 exposed cases). However due to several methodological limitations of this study such as small phenylephrine exposed sample size, recall bias, and the multiple comparisons performed, this finding likely happened by chance and is unlikely to represent a real risk. Even if the findings were real, the chance of these birth defects occurring remains uncommon (approximately 4 in 1000). No other studies, including much larger studies, found any increased risk of congenital heart defects.
No published studies were found addressing miscarriages, prematurity, or other pregnancy outcomes with use of phenylephrine in pregnancy.
Lactation:
One of the factors that helps to determine if a medication is compatible with nursing is the Relative Infant Dose (RID). The RID provides an estimate of infant’s exposure to a medication through breastmilk. It is the ratio between the infant’s and the nursing individual’s weight-adjusted doses. The infant weight adjusted dose is estimated based on the concentration of medication in breastmilk, and an assumption of infant daily milk consumption of 150 ml/kg/day. In general, for infants with normal growth and development, for infants with normal growth and development, most medications with an RID of less than 10% are considered compatible with nursing. The RID does not account for infant’s drug metabolism, clearance, or infant blood levels. Although some variability may exist in the RID, in most cases the estimated RID is adequate for clinical purposes and does not need to be calculated for each individual. We will provide the RID in the information below, when available.
There are no published studies on the transfer of phenylephrine into breastmilk.
The molecular weight of phenylephrine is 167 g/mol, therefore the molecule is small enough to pass into breastmilk. The oral bioavailability of phenylephrine is estimated to be 38%. Some data suggest that when phenylephrine is taken in combination with acetaminophen its bioavailability may double. This may increase the amount expected to pass into breastmilk. Its bioavailability is not affected when taken with ibuprofen. In Canada oral phenylephrine is available in combination preparations only, most of which contain acetaminophen.
Animal data suggest that phenylephrine decreases milk supply. No human studies on milk supply are available. When considering an oral medication, preparations not containing phenylephrine may be preferred, especially in the first month of nursing or if there are concerns about milk supply.
Nasal and ophthalmic phenylephrine preparations are not expected to decrease milk supply.
Harm Reduction:
If your patient may be using drugs or medications not as indicated during pregnancy, while providing breastmilk to an infant, or parenting please click here Harm Reduction for additional information. In case of emergency, please advise them to go to the emergency room or call 911.
For additional resources see Health Canada Drug and Natural Health Product Monographs, Making Sense of Risks and Statistics
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