Leucovorin (Injection, Intravenous, Oral)


Leucovorin is a medicine given to patients who will be taking large doses of methotrexate, which is a cancer medicine. Methotrexate can cause harmful unwanted effects when taken in large doses, and so Leucovorin acts as an antidote to help reduce those effects.

As well as this, Leucovorin is also given to treat or help prevent certain types of anemias. It has a similar function within the body as folic acid, which is low in such patients. Finally, it is also given alongside another cancer medicine called fluorouracil to help treat colon (bowel) cancer.

Be aware that this medicine is only available with a prescription from your doctor. It is known to interact with a variety of other medical conditions and drugs. As such, it is only suited to certain patients. You should be careful in following the strict guidelines your doctor gives you when using Leucovorin.

Condition(s) treated

  • Anemia

Type of medicine

  • Injectable

Side effects

As well as having its intended effects, it is possible that this medicine will cause you to experience some unwanted side effects as well. These side effects can vary in their severity and their need for medical assistance. Some patients may suffer from multiple side effects, whereas others may have none. Below is a list of the more serious side effects that can occur. If you experience any of these whilst taking Leucovorin, you should contact your doctor straight away.


  • Convulsions (seizures)

If you do experience any other side effects not listed here and find them to be worrying, then you can discuss them with your doctor.


Below you can find the typical doses of methotrexate that are prescribed to patients suffering from a variety of medical conditions. Be aware that the doses you have been given may differ greatly to what is below. That is because each patient is different and the dose is based on the extent of your condition. It is also in line with other factors, such as other medical problems you suffer from and any other drugs you are currently taking. You should not alter your doses in any way unless you have been told to do so by your doctor.

For patients taking the tablets or injection form of Leucovorin as an antidote to methotrexate:

  • Adults, teenagers, and children: Your exact dose will be based on your body weight and will need to be determined by a doctor.

For patients taking the tablets or injection form of Leucovorin as an antidote to other medicines:

  • Adults, teenagers, and children: Your dose must be calculated by a trained doctor, but will usually range from between 0.4 and 15 mg per day.

For patients taking the tablets or injection form of Leucovorin to treat certain types of anemia:

  • Adults, teenagers, and children: Take up to 1 mg per day.

For patients taking the injection form of Leucovorin to treat colon cancer:

  • Adults and teenagers: Your exact dose will be based on your body size and will need to be calculated by a doctor.

If you miss a dose of Leucovorin for any reason, you should contact your pharmacist for advice on how to proceed.

You should take this medicine exactly as instructed by your prescribing doctor. This is especially true when it is being taken as a way to help counteract the harmful effects that cancer medicine will have. You should therefore never miss any doses. You should also take your medicine at regularly spaced times of both the day and night. As an example, patients taking 4 doses a day should have each dose 6 hours apart. If you need help planning an accurate schedule, or if you find that taking this medicine interfere with certain parts of your day, then contact your doctor to decide on a suitable schedule.

It is very important that you take the exact amount of Leucovorin as prescribed to you. Also, if you wish to stop taking it then you should first discuss this with your doctor. Never stop taking it without first doing so.


It is possible that Leucovorin will interact with other medicines you are currently taking. You will, therefore, need to inform your doctor of any prescription and nonprescription drugs you are currently using. In many cases, they will try to avoid an interaction as it may interfere with your treatment. In other cases, an interaction is to be expected as using two medicines together is the best course of treatment for you. Either way, your doctor can decide whether or not they will need to change one or both of the interacting medicines or simply alter the doses of them to limit the interaction.

It is usually not recommended that you take Leucovorin at the same time as the following medicines. However, if required, then your doctor may need to alter one or both doses of the two medicines.

  • Trimethoprim

If you take any of the following medicines at the same time as Leucovorin, then you may be at an increased risk of experiencing certain side effects. Again, however, it may be that taking both medicines is the best course of treatment for you. If this is the case, then they may need to alter one or both doses you receive.

  • Tegafur

As well as interacting with other medicines, it is possible that Leucovorin will interact with certain parts of your daily dietary intake. You will, therefore, need to inform your doctor of what you typically eat, smoke, and drink. They may wish to limit how much or how frequently you consume certain things. For example, it may be necessary for you to smoke less tobacco or drink less alcohol.

Finally, other medical problems you suffer from may interact with Leucovorin. You should, therefore, inform your doctor of your complete medical history. In particular, be careful to highlight the following.

  • Vomiting and nausea. This may cause an insufficient amount of Leucovorin to be absorbed into your body to help block out the harmful effects of methotrexate


Before prescribing you with this medicine, your doctor will want to first ensure that it is the best course of treatment for you. They will, therefore, need to understand the extent of your medical health and the condition itself. As part of this, you will need to inform them of any allergies you suffer from. This includes allergies to animals, dyes, foods, and preservatives.

In pediatric patients suffering from seizures, this medicine may increase the number of seizures they experience.

This drug is just one that has not yet been studied in elderly patients. It is not known therefore if it works exactly the same in older patients as it does in younger adults. It is unclear therefore if it will cause any different side effects. Your doctor is best placed to discuss this medicine with you and to decide if it is safe and suitable for you to receive.

As of writing, it is unclear as to whether suitable studies have taken place on pregnant women taking Leucovorin. Your doctor can inform you of any increased risks to either you or your unborn child of using this medicine whilst pregnant. If you do become pregnant whilst taking this medicine, you should inform your doctor right away.

As of writing, there are no suitable studies that have taken place into the effects of this medicine on breastfeeding women. Your doctor can inform you of any increased risks and you can then weigh these together against the benefits of taking it.


You should store this medicine in a sealed container and keep it at room temperature. Do not allow it to freeze and do not expose it to direct light, moisture, or heat. You should also store it safely out of reach of children. Once you have finished your treatment, or if any medicine goes out of date, you should dispose of any remaining Leucovorin. Your pharmacist or doctor can advise you on a safe and sensible way to do so.


If you suffer from anemia, are undergoing colon cancer treatment, or are currently taking high quantities of methotrexate, then Leucovorin can be a very useful medicine to receive. Do be aware however that it is not suitable for all patients and is only given via a prescription. If you are prescribed it, then you should take it in exactly the way as advised by your doctor. Taking it more frequently or taking any more of it can cause you to experience adverse side effects. You should also follow any other lifestyle or dietary guidance that your doctor gives you. If you have any other questions about the use of Leucovorin, then these are best addressed to your prescribing doctor.