Reviewed on 9/14/2021

What Is Cycloserine Used For and How Does it Work?

Cycloserine is used to treat active tuberculosis and urinary tract infections (UTIs).

Cycloserine is available under the following different brand names: Seromycin.

Dosages of Cycloserine

Dosage Forms and Strengths


  • 250 mg

Dosage Considerations – Should be Given as Follows:

Active Tuberculosis

  • Adults, initial: 250 mg orally every 12 hours for 14 days THEN
  • Adults: 500 mg -1 g/day divided every 12 hours for 18-24 months; not to exceed 1 g/day
  • Children: 10-20 mg/kg/day orally in divided doses up to 1 g/day for 18-24 months
  • Monitor blood levels

Urinary Tract Infection (UTI)

  • Initial: 250 mg orally every 12 hours for first 14 days
  • Maintenance: 500 mg -1 g/day in divided doses; not to exceed 1 g/day
  • Monitor blood levels

Renal Impairment

  • CrCl 50-80 mL/minute: Administer every 12-16 hours
  • CrCl 10-49 mL/minute: Administer every 24-36 hours
  • CrCl less than 10 mL/minute: Administer every 36-48 hours


  • Part of multi-drug regimen; not first-line treatment


How much urine does the average adult pass each day? See Answer

What Are Side Effects Associated with Using Cycloserine?

Side effects of Cycloserine include:

What Other Drugs Interact with Cycloserine?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Cycloserine has no listed severe interactions with other drugs.

Cycloserine has no listed serious interactions with other drugs.

Moderate interactions of cycloserine include:

Cycloserine has no listed mild interactions with other drugs.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Cycloserine?


This medication contains cycloserine. Do not take Seromycin if you are allergic to cycloserine or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Hypersensitivity
  • Alcohol use
  • Renal dysfunction, severe
  • History of seizure disorder, mental depression, severe anxiety or psychosis

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Cycloserine?"

Long-Term Effects

  • Prolonged use may result in fungal or bacterial superinfection (C. difficile-associated diarrhea)
  • See "What Are Side Effects Associated with Using Cycloserine?"


  • Caution in patients with history of alcoholism (may increase seizures), anemia, impaired hepatic/renal function
  • Central nervous system (CNS) toxicity (depression, seizures, psychosis) may occur
  • Prolonged use may result in fungal or bacterial superinfection (C. difficile-associated diarrhea)

Pregnancy and Lactation

Use cycloserine with caution during pregnancy if benefits outweigh risks. Animal studies show risk and human studies are not available or neither animal nor human studies were done.

Cycloserine enters breast milk. It is considered safe for use while breastfeeding. Consult your doctor.


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