Generic Name: Cycloserine Brand Name(s): Generics only. No brands available.


What is Cycloserine used for?

Cycloserine is commonly used with other medications to treat tuberculosis (TB). In some cases, it may also be used to treat urinary tract infections (UTIs). It works by stopping the growth of bacteria.

This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.

How should I take Cycloserine?

Take this medication by mouth with or without food, usually twice daily (every 12 hours) or as directed by your doctor.

The dosage is based on your weight, medical condition, cycloserine blood levels, and response to treatment. Do not take more than 1000 mg per day.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.

Continue to take this medication (and other TB medications) until the full prescribed amount is finished, even if symptoms disappear. Stopping the medication too early or skipping doses may allow the bacteria to continue to grow, which may result in a return of the infection and cause the infection to be more difficult to treat (resistant).

Your doctor may also direct you to take vitamin B6 (pyridoxine) to help prevent certain side effects from cycloserine. Follow your doctor’s instructions carefully.

Tell your doctor if your condition persists or worsens.

How do I store Cycloserine?

Cycloserine is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Cycloserine in the bathroom or the freezer. There may be different brands of Cycloserine that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Cycloserine down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Cycloserine?

Before taking cycloserine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: seizures, mental/mood disorders (such as depression, anxiety, psychosis), kidney disease, liver disease, alcohol use.

This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages.

Cycloserine may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Cycloserine during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this Cycloserine. This Cycloserine is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Cycloserine?

Headache, drowsiness, dizziness, or shaking (tremor) may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if any of these unlikely but serious side effects occur: weakness, mental/mood changes (such as confusion, agitation, hallucination, depression, thoughts of suicide), numb/tingling skin, seizures.

Tell your doctor right away if any of these rare but seriousswelling ankles/feet, irregular heartbeat, unusual tiredness, pale skin.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with Cycloserine?

Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana, antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

Cycloserine may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Cycloserine?

Cycloserine may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Cycloserine?

Cycloserine may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.


The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Cycloserine.

What is the dose of Cycloserine for an adult?

Usual Adult Dose for Tuberculosis – Extrapulmonary

500 mg to 1 g orally per day, in 1 or 2 divided doses (10 to 15 mg/kg/day).

Duration: Treatment should continue until permanent bacteriological conversion and maximal clinical improvement have occurred, generally, 18 to 24 months.

Usual Adult Dose for Tuberculosis – Active

500 mg to 1 g orally per day, in 1 or 2 divided doses (10 to 15 mg/kg/day).

Duration: Treatment should continue until permanent bacteriological conversion and maximal clinical improvement have occurred, generally, 18 to 24 months.

Renal Dose Adjustments


CrCl<50 mL/min: 250 mg/day or 500 mg 3 times a week

The use of cycloserine is not recommended in patients with CrCl<50 mL/minute unless they are on hemodialysis.

Liver Dose Adjustments

No adjustment recommended


Cycloserine is contraindicated in patients with epilepsy, depression, severe anxiety, psychosis, or excessive alcohol use.

Cycloserine should be discontinued or the dosage reduced if allergic dermatitis or CNS toxicity (e.g., convulsions, psychosis, somnolence, depression, confusion, hyperreflexia, headache, tremor, vertigo, paresis, or dysarthria) occurs.

Blood concentrations > 30 mcg/mL are associated with toxicity. Patients taking more than 500 mg/day or with renal impairment should be closely monitored for CNS toxicity and blood concentrations monitoring should be measured weekly. Anticonvulsant agents may be helpful in controlling some symptoms. Pyridoxine may be useful in preventing CNS toxicity.

Regular hematologic, renal, hepatic, and blood level monitoring is recommended. The dose should be adjusted to maintain concentrations < 30 mcg/mL.

Due to rapid development of resistance, cycloserine should not be used alone for the treatment of tuberculosis. It should be given with other drugs to which the organism is susceptible.

Directly-observed treatment (DOT) is recommended for all antituberculosis therapy.



Hemodialysis: 250 mg once a day or 500 mg 3 times a week, after dialysis sessions.

Other Comments

Concomitant pyridoxine may be useful in preventing some neurotoxic effects.

Peak serum concentrations of 20 to 35 mcg/mL are recommended when determining dosage.

What is the dose of Cycloserine for a child?

Usual Pediatric Dose for Tuberculosis – Extrapulmonary

Children: 10 to 15 mg/kg/day in 2 divided doses

Maximum dose: 1 g/day

Usual Pediatric Dose for Tuberculosis – Active

Children: 10 to 15 mg/kg/day in 2 divided doses

Maximum dose: 1 g/day

How is Cycloserine available?

Cycloserine is available in the following dosage forms and strengths:

  • Capsule

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Cycloserine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: January 17, 2018 | Last Modified: January 18, 2018

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