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Can I take Lactulose and Pregabalin together?

Drug interaction guide

There are no known direct interactions between lactulose and pregabalin. It is generally safe to take these two medicines together.

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Why this happens

Lactulose is a laxative that works locally in the bowel and is not absorbed into the bloodstream. Pregabalin is absorbed into the blood to work on the nervous system and is cleared by the kidneys. Because they work in different ways and do not interfere with how the body processes each other, no interaction occurs.

You can continue to take both medicines as prescribed. However, be aware that pregabalin can sometimes cause constipation as a side effect; if your constipation does not improve while using lactulose, you should speak with your doctor or pharmacist.

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Pregnancy

Pregabalin use during the first three months of pregnancy may increase the risk of birth defects. Effective contraception must be used during treatment.

Respiratory depression

Pregabalin can cause severe breathing problems, especially if you already have lung disease or if you take it with other medicines that cause drowsiness or contain opioids.

Drug dependence and withdrawal

Pregabalin can lead to dependence and addiction. Do not stop taking this medicine suddenly, as this can cause serious withdrawal symptoms such as seizures, anxiety, and insomnia. Your dose must be reduced gradually.

Galactosaemia

You must not take lactulose if you have galactosaemia, a rare genetic disorder where your body cannot process galactose.

Diabetes

If you are taking high doses of lactulose for liver disease (portal systemic encephalopathy), the sugar content may affect your blood glucose levels.

Alcohol

It is best to avoid or strictly limit alcohol while taking pregabalin. Combining alcohol with this medicine can significantly increase the risk of side effects such as extreme sleepiness, dizziness, and breathing difficulties.

It is best to avoid or strictly limit alcohol when taking lactulose. Alcohol can cause dehydration, which may worsen the constipation you are trying to treat. Additionally, if you are taking lactulose for liver disease (hepatic encephalopathy), alcohol must be avoided entirely as it can significantly worsen your condition.

Water and Fluids

It is essential to drink plenty of fluids (such as water) while taking lactulose. This medicine works by drawing water into the bowel to soften stools; if you do not drink enough, the medicine may not work effectively and you may become dehydrated.

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Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.

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Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • 25 Jan 2026 | Originally published
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