Low Dose Naltrexone

We frequently deal with prescriptions for Low Dose Naltrexone also known as "LDN". LDN is an unlicensed medicine and is only available on a prescription from your doctor. The usual dosage of LDN is either 3mg or 4.5mg. We supply both capsule and liquid form of LDN to suit our customers needs.

If you have any questions or would like advice on LDN just give us a call on +353 91 764185, email at info@ipharm.ie or call into us, we would be more than happy to help in any way we can! Below are some of the most frequently asked questions regarding Low Dose Naltrexone.

What is LDN?

LDN is short for Low Dose Naltrexone. Naltrexone is a drug that was approved by the FDA (Food and Drugs Authority) in 1985 to treat opiate dependence, and is used at a dose of 50mg - 100mg for this purpose.

LDN refers to the use of Naltrexone at low doses, usually between 3mg - 10mg per day. At these doses it exhibits novel and paradoxical effects. Numerous lab and animal studies have been carried out to investigate its novel effects in cancer and autoimmune disorders. Further studies are ongoing.

How does LDN work?

LDN works by increasing endorphin levels in the body. Endorphins are opiate-like molecules produced naturally in the body that are regulators of cell growth & the immune system. Disorders of the immune system can occur when levels of these endorphins are excessively low. The particular endorphin involved is called Opiod Growth Factor (OGF) or Met-Enkephalin. OGF works by binding to a receptor called the OGF Receptor.

LDN also binds to opioid receptors and displaces the bodys OGF. As a result the body responds by;

  • Increasing receptor production to capture more OGF.
  • Increasing OGF receptor sensitivity
  • Producing more OGF

LDN blocks the receptors for only a few hours (intermittent opioid receptor blockade) resulting in a rebound effect, where more OGF is produced and used, interacting with the more sensitive & more plentiful receptors.

What is the correct dose of LDN?

LDN works through a " rebound effect", and as a result its beneficial effects only begin taking place once the LDN has been metabolized and removed from the cells. This process varies between individuals, and so there is no single dose that will work for every person. Typical doses vary from as low as 2mg to 10mg. The clinical trials so far have used a single daily dose of 4.5mg and for most users this dose seems to be effective.

When is the best time of the day to take LDN?

Most patients take LDN at night between 9pm and 2am, however sometimes it can disturb sleep in certain individuals. The clinical trials conducted so far have not shown any difference in effect if LDN is taken at night or in the morning.

Does LDN need to be taken without food?

Food is not known to affect the absorption of Naltrexone and so it may be taken with or without food.

What side effects will I experience?

Most people will experience few or no side effects from LDN. If you do experience side effects they are usually mild and tend to subside within two weeks of taking LDN. Typical side effects are sleep disturbance, vivid dreams, nausea, headache and dry mouth.

Can LDN be combined with painkillers?

LDN can be safely combined with certain types of painkillers such as NSAIDS (Ibuprofen), paracetamol and similar drugs. Over the counter codeine containing products should be avoided when taking LDN.

Can LDN be used with opiate type painkillers?

LDN can neutralize the effects of opiates or opiate-like painkillers if taken together so if possible they should not be used together. LDN is metabolized by the body within a few hours. If opiates and LDN are kept apart by a few hours, LDN should not interfere with the pain-relieving effects of opiates. LDN should never be taken with sustained release or prolonged release opiates whether in oral or patch form. ALWAYS CHECK WITH YOUR PHARMACIST.

How soon after taking LDN can you take an opiate painkiller?

It will take 4-6 hours (with individual variation) for LDN to be metabolized, and therefore enable the opiate to relieve pain. There is no harm in taking the painkiller sooner, except that it may not work.

Is it safe to combine LDN with alcohol?

There is conflicting evidence as to whether LDN and alcohol interact. Some patients experience no ill effects while some have reported nausea and an increased ‘hangover’ effect.

Does the filler used in LDN capsules have an influence on its effectiveness?

Yes, certain fillers such as calcium carbonate may interfere with rapid absorption of LDN. Also, some patients are intolerant of certain fillers such as lactose. The capsules we supply to our patients do not contain calcium carbonate or lactose fillers.

Is it safe to use LDN whilst trying to conceive or during pregnancy?

There have been reports of use of LDN before and during pregnancy with no ill effects. In fact in many individuals use of LDN during pregnancy appears to have a beneficial effect. However you should check with your doctor before taking LDN while pregnant or while trying to conceive.

Should LDN be stopped before surgery?

Yes, LDN should be stopped 2-3 days before surgery or at the very latest 24 hours prior to surgery.

Is LDN an immune-suppressive drug?
LDN is best classified as an immuno-regulator. It regulates proliferation of all cells, including immune cells (T-cells and B-cells). When immune cells are being produced in excess (leading to autoimmune conditions), LDN acts to slow down their proliferation.
Can your body become accustomed to LDNs rebound effect?

In theory yes, and so it may make sense if LDN is losing its effectiveness to take a break from using it every so often. This question has not yet been addressed in clinical trials.

The following websites provide accurate and detailed information about Low Dose Naltrexone and its uses:


Also have a look at our "useful links" page at the bottom of the homepage. Over the years we have built up considerable expertise on the use of LDN for various conditions so if you have any further queries please contact us.