cycloserine at a glance
Medicine class
Antimycobacterial antibiotic that blocks bacterial cell-wall formation.
Usual role
Part of specialist combination treatment for susceptible, drug-resistant tuberculosis.
Administration
Swallow the hard capsules whole with water. Avoid alcohol.
Important safety issue
Mental-health and neurological reactions can occur, particularly when clearance is reduced.
What is cycloserine used for?
UK-licensed uses are:
Pulmonary or extrapulmonary tuberculosis, including renal disease, when susceptibility is established and adequate primary treatment has failed. It is used in combination treatment.
Acute urinary tract infection caused by susceptible bacteria when conventional treatment has failed. It may be less effective than standard antibiotics for non-mycobacterial infections.
How does cycloserine work?
Cycloserine competes with D-alanine, disrupting enzymes needed to construct the bacterial cell wall. This inhibits susceptible tuberculosis bacteria and some other bacteria.
How to take cycloserine
Take cycloserine exactly as directed by the specialist team. Swallow the hard capsules whole with water. Avoid alcohol because it increases seizure risk.
Do not share the capsules.
Tell the team promptly about neurological or mental-health symptoms.
cycloserine side effects
Common or expected effects
- Reported effects of unknown frequency include headache, dizziness, drowsiness, tremor, pins and needles, confusion, and mood or personality changes.
- Blood-test changes can include anaemia or raised liver enzymes.
Get urgent medical advice
- Seizures, psychosis, hallucinations, suicidal thoughts, severe confusion, slurred speech, limb weakness or coma.
- A serious allergic reaction causing widespread itching or rash, wheezing, breathing difficulty, or swelling of the face, lips or eyelids.
- Sudden shortness of breath that could indicate heart failure.
cycloserine in pregnancy
Human evidence is limited, and cycloserine reaches the fetal circulation. UK product information advises use only when clearly needed after specialist assessment of benefits and uncertain fetal risks.
cycloserine while breastfeeding
Cycloserine passes into breast milk. Breastfeeding and treatment require an individual specialist decision; infant monitoring may be appropriate.
cycloserine interactions
Important interactions include:
Ethionamide
Combined use may increase neurotoxic effects.
Isoniazid
Combined central-nervous-system toxicity may increase dizziness, drowsiness and related symptoms.
Alcohol
Increases seizure risk and should be avoided.
Common questions about cycloserine
Answers are fully visible for fast scanning and source review.
Is cycloserine an antibiotic?
Yes. It is an antimycobacterial antibiotic that disrupts bacterial cell-wall formation.
Can it be used alone for tuberculosis?
No. Its UK licence specifies use with other effective tuberculosis treatment.
Can it treat a urinary tract infection?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.