Cycloserine Capsules

Name: Cycloserine Capsules

Clinical pharmacology section

After oral administration, cycloserine is readily absorbed from the gastrointestinal tract, with peak blood levels occurring in 4 to 8 hours.
Blood levels of 25 to 30 μg/mL can generally be maintained with the usual dosage of 250 mg twice a day, although the relationship of plasma levels to dosage is not always consistent. Concentrations in the cerebrospinal fluid, pleural fluid, fetal blood, and mother’s milk approach those found in the serum. Detectable amounts are found in ascitic fluid, bile, sputum, amniotic fluid, and lung and lymph tissues. Approximately 65 percent of a single dose of cycloserine can be recovered in the urine within 72 hours after oral administration. The remaining 35 percent is apparently metabolized to unknown substances. The maximum excretion rate occurs 2 to 6 hours after administration, with 50 percent of the drug eliminated in 12 hours.

Indications & usage section

Cycloserine is indicated in the treatment of active pulmonary and extrapulmonary tuberculosis (including renal disease) when the causative
organisms are susceptible to this drug and when treatment with the primary medications (streptomycin, isoniazid, rifampin, and ethambutol) has proved inadequate. Like all antituberculosis drugs, cycloserine should be administered in conjunction with other effective chemotherapy and not as the sole therapeutic agent.
Cycloserine may be effective in the treatment of acute urinary tract infections caused by susceptible strains of gram–positive and gram–negative bacteria, especially Enterobacter spp. and Escherichia coli. It is generally no more and is usually less effective than other antimicrobial agents in the treatment of urinary tract infections caused by bacteria other than mycobacteria. Use of cycloserine in these infections should be considered only when more conventional therapy has failed and when the organism has been demonstrated to be susceptible to the drug.

Pregnancy section

Pregnancy Category C

A study in 2 generations of rats given doses up to 100 mg/kg/day demonstrated no teratogenic effect in offspring. It is not known whether cycloserine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Cycloserine should be given to a pregnant woman only if clearly needed.

Dosage & administration section

Cycloserine is effective orally and is currently administered only by this route. The usual dosage is 500 mg to 1 g daily in divided doses monitored by blood levels.2 The initial adult dosage most frequently given is 250 mg twice daily at 12–hour intervals for the first 2 weeks. A daily dosage of 1 g should not be exceeded.

How supplied section

Cycloserine is available as a 250 mg capsule with an opaque red cap and opaque gray body imprinted with “CHAO” and “F04” in edible black ink on both the cap and the body.

 Bottles of 40  NDC 13845-1201-3

Store at controlled room temperature, 20° to 25°C (68° to 77°F) [see USP].

References section

1. Kubica GP, Dye WE: Laboratory methods for clinical and public health - mycobacteriology, US Department of Health, Education, and Welfare, Public Health Services, 1967, pp47-55, 66-70.

2. Jones LR: Colorimetric determination of cycloserine, a new antibiotic. Anal Chem 1956; 28:39.

The Chao Center for Industrial Pharmacy and Contact Manufacturing  West Lafayette, IN, 47906, USA

Literature revised 14 JANUARY 2009