Laxatives for children
This page contains info specific to the laxatives themselves, such as dosages. For more information about constipation, see our webpage here.
Miralax
This is a good choice for children because it is more effective with fewer side effects than other laxatives. It works because it can’t be absorbed: the water it’s dissolved in stays in the poop, preventing it from getting hard or dry. This is also why it’s so safe, whatever you ingest only comes out the other end. Other laxatives tend to have some form of medicated effect. Because Miralax works via purely physical means, the dosage is based on how much of that physical effect you need - more will make poops softer/more hydrated, less will leave them harder/drier, and you adjust your dose until the poops have the desired hydration/softness.
Dosage
Start with the suggested starting dose by age, then increase by the suggested adjustment until your child has daily poops that are nice and soft (“soft serve ice cream” consistency).
Mixing: Each 1 teaspoon of Miralax must be dissolved in at least 1 ounce of liquid. Each capful should have at least 4 oz liquid. You can dilute further (eg 1 capful in 8 ounces) but don’t make them more concentrated. It can be given either once daily or divided into two smaller doses per day.
Infants < 6 months: make sure you’ve checked with us first as constipation is rare at this age. If laxative advised, start: 1/4 tsp daily, adjust by: 1/4 tsp at a time. Common range: 1/4 to 1 tsp per day.
Infants 6-12 months: start: 1/2 tsp daily, adjust by 1/4 to 1/2 tsp at a time. Common range: 1/2 to 2 tsp per day.
Children 12-24 months: start: 1 tsp daily, adjust by 1/2 tsp at a time. Common range: 1.5 to 4 tsp per day.
Children 2-3 years: start: 2 tsp daily, adjust by 1/2 to 1 tsp at a time. Common range: 2 to 6 tsp per day.
Children 4-5 years: start: 3 tsp daily, adjust by 1 tsp at a time. Common range: 3 to 8 tsp per day.
Children 6+ years: start: 1 capful daily, adjust by 1/2 capful at a time. Common range: 1 to 2 capfuls per day.
Note that these are only rough guidelines; there is no absolute min/max as long as your child is tolerating well and having the desired outcome. So be sure to monitor the stool output during treatment and adjust until you achieve the desired effect.
Miralax can be used in a variety of different situations. The above suggestions are most applicable to maintaining soft daily stools over time. That might be for preventive situations like during vacation or camp when kids often get constipated, or for treatment when they need relief for a couple weeks after a temporary backup with some hard poops, or for maintenance and rehabilitation for 12-18 months after a disimpaction. Miralax can also be used for disimpaction, but this dosing is quite different and will be provided to you after an office visit for impaction.
Senna
Senna is a medication that causes contraction of the colon to speed up transit. It’s particularly useful for children who are withholding, got backed up, or need to push something through that’s a bit stuck. It’s also convenient for camps or travel because it comes in compact chocolate squares. However it can cause some cramping, so be mindful of that. It’s also not ideal for long term use as it can be habit forming, and there is a known side effect, though benign, in some people who take it a lot where the colon becomes darker in color. You don’t have to worry about that with short term use however.
Dosage: It takes a while to take effect, so to trigger an evening poop give it in the morning, and for a morning poop, give before bed (don’t worry, kids typically won’t need to poop until they wake up).
Children 2-3 years: 1/4 to 1/3 of a 15 mg chocolate Ex-Lax square 1-2 times daily. If in diapers, try to clean poop off butt cheeks ASAP as this can cause irritation to perianal skin.
Children 4-6 years: 1/3 to 1/2 of a 15 mg chocolate Ex-Lax square 1-2 times daily. Can go up to 1 full square if not responding to 1/2 square.
Children 6-11 years: 1/2 to 1 chocolate Ex-Lax square 1-2 times daily.
Children 12+ years: 2 chocolate Ex-Lax squares 1-2 times daily.
Other laxatives
There are many other laxatives such as magnesium, lactulose and more, but we use these commonly unless there’s a specific need because of side effects. For children old enough to be in the products recommended age, if you do prefer these you can follow the instructions on the product, otherwise schedule a visit with us to discuss your child’s laxative needs.
