Medications, alcohol and cannabis in breastfeeding

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Learn about the potential effects of using alcohol or cannabis/marijuana while breastfeeding and how to maximize safety when using medications or supplements.

Key points

  • Most medications are safe to take while breastfeeding. However, if you cannot find this information on the packaging, make sure to check with your health-care provider, lactation consultant or pharmacist before you take any prescription or over-the-counter medications, including herbal products or supplements.
  • If you are not sure about the safety of a new medication, you can pump and store your breastmilk until you check with your health-care provider.
  • The safest option for breastfeeding mothers is not to drink alcohol or use cannabis/marijuana.

The terms 'mother' and 'breastfeeding' are used throughout our documents; we recognize and respect that individuals and families may use other preferred terminology.

If you are breastfeeding and need to take medication, you should still be able to breastfeed in most cases, as the amount of medication passed to your baby is very small. Alcohol and cannabis also pass to the baby via breastmilk. If you consume alcohol or cannabis and cannot totally avoid consuming them, they should only be consumed infrequently and in moderation.

Medications and breastfeeding

Breast milk is the best food for your baby because it not only provides ideal nutrition but also provides many benefits, including lowering their number of childhood infections, increasing their IQ and reducing their risk of obesity and asthma. Women should not feel that breastfeeding must stop if they need to take a medication.

It is important to keep in mind that although many drugs can pass through your breast milk to your baby, the amount that reaches your baby is very small. As a result, the vast majority of medications are safe to take when breastfeeding. Very rarely, some prescription medications (especially in combination) that have a chance of side effects may require your baby to be followed more closely.

Over-the-counter pain medications (ibuprofen, acetaminophen) and most prescription pain medications taken in the days after childbirth should be safe for breastfeeding. However, research suggests that opioids such as codeine, morphine, hydromorphone and fentanyl can all cause sleepiness in infants and rarely more severe neurologic effects. Opioid use in breastfeeding mothers should be limited to low dosage for short periods of time, and alternatives to pain control should be considered.

A few prescription drugs should be used with caution and medical supervision. The rare drugs that should NOT be taken while breastfeeding include anticancer/chemotherapy drugs, amiodarone, chloramphenicol, radioactive agents, tetracycline and illegal drugs. This list is not all-inclusive.

Make sure to check with your health-care provider, lactation consultant or pharmacist before you take any medications, including herbal and over-the-counter products/supplements, while breastfeeding. Your health-care professional can provide information about the safety of these medications while breastfeeding. Depending on the medication, they may also need to do some specific follow-up. Additional information about medications and breastfeeding may be found at

Alcohol and breastfeeding

Abstaining from drinking alcohol during pregnancy is important to prevent the effects of fetal alcohol spectrum disorder. As alcohol does pass into breastmilk, there may be some risks associated with consuming alcohol during breastfeeding, such as infant sleepiness. Additionally, frequent use of alcohol can affect the milk “let down” reflex and milk supply, making breastfeeding more difficult. Most importantly, it is not safe to care for your baby while intoxicated.

When a breastfeeding mother drinks alcohol, it passes into her breast milk at concentrations similar to that in her own bloodstream. It takes at least two to three hours for a standard drink to clear from breast milk. It is understood that some mothers may choose to have an occasional drink with a meal while breastfeeding; in order to maximize safety, pump or breastfeed the baby then wait at least two to three hours before pumping or feeding again.

It is recommended to pump/express and discard the breastmilk if a breastfeeding session falls within the wait-time interval. You should give your baby previously pumped breast milk during this time.

Cannabis (marijuana) and breastfeeding

Although cannabis is legal in Canada and is a natural substance, it is not necessarily safe during breastfeeding, regardless of the method of consumption (smoked, eaten in foods/candy, absorbed through oils, etc.). There is evidence that suggests using cannabis during pregnancy could be harmful to the baby, causing poor fetal growth and behavioural problems that emerge during school age.

There is not a lot of information on the use of cannabis and breastfeeding. However, using cannabis during breastfeeding is strongly discouraged, as it does pass into the breast milk and can possibly affect the baby. If a breastfeeding mother cannot stop the use of cannabis, it can be helpful for her to reduce how much she consumes and the strength (THC content; the “high” substance in cannabis) of the cannabis. THC can build up in the mother’s body and transfer into breast milk, so frequent or chronic use of cannabis likely causes higher levels of THC in breast milk than occasional use. Similar to alcohol, it is recommended that if a mother does occasionally use inhaled cannabis, she should wait three to four hours after use before breastfeeding to reduce how much THC is in her milk. Cannabis smoke, like tobacco smoke, is also unhealthy for babies (and all people) to be around. There is no published information on non-inhaled forms of cannabis and breastfeeding. However, in studies of non-lactating people, these products (edibles, for example) usually result in lower THC blood levels but stay in the blood much longer, making timing for “pumping and dumping” a challenge. Importantly, it is never safe to take care of an infant while smoking, high or impaired.

Premature babies

It is important to note that infants born prematurely who are admitted to the NICU may be more susceptible to any side effects of medications or substances in breast milk. If you are breastfeeding or expressing breast milk for a premature baby, consuming any amounts of alcohol or cannabis is NOT recommended. Consult with your health-care provider if you need to take medications or supplements of any kind.

Last updated: June 19th 2024