Folate is a form of B vitamin that occurs naturally in many foods. Folic acid is the man-made form of folate that is added to processed foods or vitamin and mineral supplements. Folate is needed in the human body for production of red blood cells.

A lack (deficiency) of folate in the human body can be caused by certain diseases, by taking certain medications, or by not getting enough folate in your diet. Folate deficiency can lead to decreased red blood cells, or anemia. Folate deficiency can also cause high levels of a certain amino acid in the blood, a condition called hyperhomocysteinemia (HYE-per-HOE-moe-sis-tin-EE-mee-a).

XaQuil XR is a medical food for use in people who have conditions related to folate deficiency. This medicine is also used in people with major depressive disorder who have folate deficiency, or in people with schizophrenia who have hyperhomocysteinemia related to folate deficiency.

XaQuil XR is not an antidepressant or anti-psychotic medication. However, this medicine may enhance the effects of antidepressant medications.

XaQuil XR may also be used for purposes not listed in this medication guide.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Follow all directions on your prescription label. Do not take XaQuil XR in larger or smaller amounts or for longer than recommended.

Use only the strength of l-methylfolate that your doctor has prescribed. Do not switch brands without your doctor's advice.

You may take XaQuil XR with or without food. Follow your doctor's instructions.

Do not crush, chew, or break an extended-release tablet. Swallow it whole.

Do not share this medication with another person, even if they have the same symptoms you have.

XaQuil XR is only part of a complete program of treatment that may also include other medications, and psychological counseling when used in people with depression or schizophrenia. Follow your medication and counseling routines very closely.

Store at cool room temperature away from moisture, heat, and light.

You should not use XaQuil XR if you are allergic to it.

To make sure XaQuil XR is safe for you, tell your doctor if you have:

• seizures or epilepsy;

• a history of vitamin B12 deficiency or pernicious anemia; or

• a history of bipolar disorder (manic depression).

Tell your doctor if you are pregnant or breast-feeding. Your dose needs may be different during pregnancy or while you are nursing.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

An overdose of XaQuil XR is not likely to cause life-threatening symptoms.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects may occur, and you may have none at all.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your current medicines and any you start or stop using, especially:

• capecitabine;

• fluoxetine (Prozac);

• isotretinoin;

• methotrexate;

• methylprednisolone;

• pancrelipase;

• pyrimethamine;

• triamterene;

• trimethoprim;

• warfarin (Coumadin, Jantoven);

• birth control pills;

• oral diabetes medicine that contains metformin (Glucophage, Avandamet, Metaglip, and others);

• NSAIDs (nonsteroidal anti-inflammatory drugs)--aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others; or

• seizure medicine--carbamazepine, lamotrigine, phenobarbital, phenytoin, primidone, valproic acid.

This list is not complete. Other drugs may interact with l-methylfolate, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.