Kristalose (lactulose) is an osmotic laxative. It's used to help relieve constipation in adults. Kristalose (lactulose) comes as a powder packet with 10 grams of lactulose per packet. The usual dosage is to dissolve 1 to 2 packets of Kristalose (lactulose) in water and to take by mouth daily. After you start treatment, it can take up to two days before you have a bowel movement. Some common side effects of Kristalose (lactulose) include stomach cramps and passing gas.
Kristalose (lactulose) is an osmotic laxative. It eases constipation by drawing more fluid into the gut. This helps soften the stool and makes it easier to pass.
Source:Â DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
For bulk-forming-containing
Difficulty in breathing
intestinal blockage
skin rash or itching
swallowing difficulty (feeling of lump in throat)
For hyperosmotic-containing
Confusion
dizziness or light-headedness
irregular heartbeat
muscle cramps
unusual tiredness or weakness
For stimulant-containing
Confusion
irregular heartbeat
muscle cramps
pink to red, red to violet, or red to brown coloration of alkaline urine (for cascara, danthron, and/or senna only)
skin rash
unusual tiredness or weakness
yellow to brown coloration of acid urine (for cascara, and/or senna only)
For stool softener (emollient)-containing
Skin rash
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
For lubricant-containing
Skin irritation surrounding rectal area
For stool softener (emollient)-containing
Stomach and/or intestinal cramping
throat irritation (liquid forms only)
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Comes as convenient single-dose packets
Might be a good option for people with constipation who didn’t see benefits with OTC laxatives
Typically taken once daily
Not appropriate for people on a low-galactose diet
Not a first-choice laxative because of the side effects
Need to mix with water, so can be inconvenient
You need to mix the Kristalose (lactulose) powder packet in water before taking it. Each packet should be mixed in half a glass (4 ounces) of water. After it's mixed, the solution should be colorless to a slightly pale yellow color.
Talk with your healthcare team if you've questions about how Kristalose (lactulose) might affect your blood sugar. Kristalose (lactulose) does contain galactose and lactose, which are two types of sugars. But limited research shows that Kristalose (lactulose) isn't likely to raise your blood sugar levels.
Kristalose (lactulose) might cause diarrhea if your dose is too high. This can cause you to lose water and feel dehydrated, so make sure you drink enough fluids to make up for the loss. If you have diarrhea, let your healthcare team know. They can lower your dose of Kristalose (lactulose) and let you know if you need more medical attention.
Make sure to tell your healthcare team if you're lactose intolerant. Kristalose (lactulose) contains lactose, which might cause people with this condition to have bloating, cramping, and diarrhea.
Don’t take antacids, like Mylanta Maximum Strength (aluminum hydroxide / magnesium hydroxide / simethicone) or calcium carbonate (Tums), at the same time as Kristalose (lactulose). They might cause Kristalose (lactulose) to not work as well. If you need medications for heartburn, ask your healthcare team about other options that won't interact with Kristalose (lactulose).
There aren't enough studies about whether Kristalose (lactulose) is safe during pregnancy. But Kristalose (lactulose) might not be appropriate to take during pregnancy because it can cause nausea and bloating, which can be very uncomfortable. If you have plans to get pregnant, ask your healthcare team about safer options to treat constipation.
Kristalose (lactulose) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Taking Kristalose (lactulose) for more than 6 months | Age 65 years and older | Taking medications that cause electrolyte imbalances
Kristalose (lactulose) can make you dehydrated which can affect your body's mineral levels. Electrolytes (minerals), such as sodium, potassium, and calcium, have many important functions in the body. Your healthcare professional (HCP) might want to check these regularly while you're taking Kristalose (lactulose), especially if you’re older in age or have been taking Kristalose (lactulose) for a long period of time. Call your HCP right away if you feel extremely thirsty, tired, or confused because these are signs that Kristalose (lactulose) might be making you dehydrated and affecting your electrolyte levels.
Risk factors: Diabetes
Be mindful that Kristalose (lactulose) contains galactose and lactose, which are both forms of sugar. If you have high blood sugar, it's best to check your blood sugar levels regularly while taking Kristalose (lactulose). Limited research shows that Kristalose (lactulose) doesn't seem to cause a spike in blood sugar, but you're still recommended to check your blood sugar levels just in case.
If you're planning to have a colonoscopy or a rectal exam, let your healthcare team know you're taking Kristalose (lactulose). Your HCP might have you take different medications to clean out your gut before your exam.
Each Kristalose (lactulose) packet either contains 10 or 20 grams of lactulose. To prepare, each packet needs to be dissolved in 4 oz of water.
The typical dose is to dissolve 1 to 2 packets of Kristalose (lactulose) in water and then to take by mouth daily. The maximum recommended dose is 40 grams daily.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking any of these medicines, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using medicines in this class with any of the following medicines is not recommended. Your doctor may decide not to treat you with a medication in this class or change some of the other medicines you take.
Using medicines in this class with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
People who need a low-galactose diet
Occasional constipation and irregular bowel movements
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Bosch, A. M. (2011). Classic galactosemia: Dietary dilemmas. Journal of Inherited Metabolic Disease.
Chartwell RX, LLC. (2024). Lactulose solution [package insert]. DailyMed.
Cumberland Pharmaceuticals Inc. (2018). Kristalose- lactulose powder, for solution [package insert]. DailyMed.
Longo, S. A., et al. (2010). Gastrointestinal conditions during pregnancy. Clinics in Colon and Rectal Surgery.
Steudle, J., et al. (2018). Blood glucose response after oral intake of lactulose in healthy volunteers: A randomized, controlled, cross-over study. World Journal of Gastrointestinal Pharmacology and Therapeutics.
Włodarczyk, J., et al. (2021). Current overview on clinical management of chronic constipation. Journal of Clinical Medicine.
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