Leucovorin Calcium Tablets USP

Rx only

Leucovorin Calcium Tablets USP contain either 5 mg or 25 mg leucovorin as the calcium salt of N-[4-[[(2-amino-5-formyl-1, 4, 5, 6, 7, 8-hexahydro-4-oxo-6-pteridinyl)methyl] amino]benzoyl]- L-glutamic acid. This is equivalent to 5.4 mg or 27.01 mg of anhydrous leucovorin calcium, respectively. In addition, each tablet contains the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, lactose monohydrate, magnesium stearate, and microcrystalline cellulose. The 25 mg tablet also contains D&C yellow no. 10 aluminum lake and FD&C blue no. 1 aluminum lake.

Leucovorin is a water soluble form of reduced folate in the folate group; it is useful as an antidote to drugs which act as folic acid antagonists. These tablets are intended for oral administration only.

The structural formula is as follows:

C ₂₀H ₂₁CaN ₇O ₇ M.W. 511.5

Leucovorin is a racemic mixture of the diastereoisomers of the 5-formyl derivative of tetrahydrofolic acid. The biologically active compound of the mixture is the (-)- L-isomer, known as Citrovorum factor, or (-)-folinic acid. Leucovorin does not require reduction by the enzyme dihydrofolate reductase in order to participate in reactions utilizing folates as a source of “one-carbon” moieties. Following oral administration, leucovorin is rapidly absorbed and enters the general body pool of reduced folates. The increase in plasma and serum folate activity (determined microbiologically with Lactobacillus casei) seen after oral administration of leucovorin is predominantly due to 5-methyltetrahydrofolate.

Twenty normal men were given a single, oral 15 mg dose (7.5 mg/m ²) of leucovorin calcium and serum folate concentrations were assayed with L. casei. Mean values observed (± one standard error) were:

1. Time to peak serum folate concentration: 1.72 ± 0.08 hours,
2. Peak serum folate concentration achieved: 268  ± 18 ng/mL,
3. Serum folate half-disappearance time: 3.5 hours.

Oral tablets yielded areas under the serum folate concentration-time curves (AUCs) that were 12% greater than equal amounts of leucovorin given intramuscularly and equal to the same amounts given intravenously.

Oral absorption of leucovorin is saturable at doses above 25 mg. The apparent bioavailability of leucovorin was 97% for 25 mg, 75% for 50 mg and 37% for 100 mg.

Leucovorin calcium tablets are indicated to diminish the toxicity and counteract the effects of impaired methotrexate elimination and of inadvertent overdosages of folic acid antagonists.

Leucovorin is improper therapy for pernicious anemia and other megaloblastic anemias secondary to the lack of vitamin B ₁₂. A hematologic remission may occur while neurologic manifestations continue to progress.

In the treatment of accidental overdosage of folic acid antagonists, leucovorin should be administered as promptly as possible. As the time interval between antifolate administration (e.g., methotrexate) and leucovorin rescue increases, leucovorin’s effectiveness in counteracting hematologic toxicity decreases.

Monitoring of the serum methotrexate concentration is essential in determining the optimal dose and duration of treatment with leucovorin.

Delayed methotrexate excretion may be caused by a third space fluid accumulation (i.e., ascites, pleural effusion), renal insufficiency, or inadequate hydration. Under such circumstances, higher doses of leucovorin or prolonged administration may be indicated. Doses higher than those recommended for oral use must be given intravenously.

Leucovorin may enhance the toxicity of fluorouracil. Deaths from severe enterocolitis, diarrhea, and dehydration have been reported in elderly patients receiving weekly leucovorin and fluorouracil. ¹ Concomitant granulocytopenia and fever were present in some but not all of the patients.

The concomitant use of leucovorin with trimethoprim-sulfamethoxazole for the acute treatment of Pneumocystis carinii pneumonia in patients with HIV infection was associated with increased rates of treatment failure and mortality in a placebo-controlled study.

Allergic sensitization, including anaphylactoid reactions and urticaria, has been reported following the administration of both oral and parenteral leucovorin.

To report SUSPECTED ADVERSE REACTIONS, contact Teva Pharmaceuticals USA, Inc. at 1-888-838-2872 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Excessive amounts of leucovorin may nullify the chemotherapeutic effect of folic acid antagonists.

Leucovorin calcium tablets are intended for oral administration. Because absorption is saturable, oral administration of doses greater than 25 mg is not recommended.

Leucovorin Calcium Tablets USP, 5 mg are available as white, round, unscored, biconvex tablets, debossed with b on one side and 484 on the other side. They are available as follows:

NDC 51079-581-06 – Unit dose blister packages of 50 (5 cards of 10 tablets each).

Leucovorin Calcium Tablets USP, 25 mg are available as pale green, round, unscored, biconvex tablets, debossed with b on one side and 485 on the other side. They are available as follows:

NDC 51079-582-05 – Unit dose blister packages of 20 (2 cards of 10 tablets each).

Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.] Protect from light and moisture.

KEEP THIS AND ALL MEDICATIONS OUT OF THE REACH OF CHILDREN.

1. Grem JL, Shoemaker DD, Petrelli NJ, Douglas HO. Severe and fatal toxic effects observed in treatment with high- and low-dose leucovorin plus 5-fluorouracil for colorectal carcinoma. Cancer Treat Rep 1987;71:1122.
2. Link MP, Goorin AM, Miser AW et al. The effect of adjuvant chemotherapy on relapse-free survival in patients with osteosarcoma of the extremity. N Engl J Med 1986;314:1600-1606.

Manufactured In Bulgaria by:
Balkanpharma Dupnitsa AD
Dupnitsa 2600, Bulgaria

Manufactured for:
Teva Pharmaceuticals USA, Inc.
North Wales, PA 19454

S-12737
7/21

NDC 51079-581-06

Leucovorin Calcium
Tablets, USP
5 mg*

50 Tablets (5 x 10)

*Each tablet contains leucovorin calcium,
USP equivalent to 5 mg leucovorin.

Usual Dosage: See accompany
prescribing information.

Store at 20° to 25°C (68° to 77°F). [See USP
Controlled Room Temperature.] Protect
from light and moisture.

Manufactured In Bulgaria by:
Balkanpharma Dupnitsa AD
Dupnitsa 2600, Bulgaria

Manufactured for:
Teva Pharmaceuticals USA, Inc.
North Wales, PA 19454

Rx only

S-12739

Distributed by:

Mylan Institutional Inc.

Rockford, IL 61103 U.S.A.

This unit dose package is not child resistant.

For institutional use only.

Keep this and all drugs out of the reach of children.

This container provides light-resistance.

See window for lot number and expiration date.

NDC 51079-582-05

Leucovorin Calcium
Tablets, USP
25 mg*

20 Tablets (2 x 10)

*Each tablet contains leucovorin calcium,
USP equivalent to 25 mg leucovorin.

Usual Dosage: See accompany
prescribing information.

Store at 20° to 25°C (68° to 77°F). [See USP
Controlled Room Temperature.] Protect
from light and moisture.

Manufactured In Bulgaria by:
Balkanpharma Dupnitsa AD
Dupnitsa 2600, Bulgaria

Manufactured for:
Teva Pharmaceuticals USA, Inc.
North Wales, PA 19454

Rx only

S-12738

Distributed by:

Mylan Institutional Inc.

Rockford, IL 61103 U.S.A.

This unit dose package is not child resistant.

For institutional use only.

Keep this and all drugs out of the reach of children.

This container provides light-resistance.

See window for lot number and expiration date.