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cycloserine

Generic Seromycin
Used for Urinary Tract Infection, Tuberculosis
Used for Urinary Tract Infection, Tuberculosis

Cycloserine (Seromycin) is an antibiotic that's used to treat tuberculosis (TB) and urinary tract infections (UTIs) in adults. It's usually only used for treating drug-resistant infections (when typical antibiotics don't work). This medication is a capsule that's taken by mouth. At higher doses, it can cause side effects, including sleepiness, headache, confusion, changes in personality, and even seizures. Treatment requires frequent monitoring of medication levels in the blood to prevent side effects.

Reviewed by:
reviewer
Aileen Chu, PharmD, BCPS
reviewer
Cydnee Ng, PharmD
Last reviewed on December 4, 2023
BasicsSide effectsPros & consPharmacist tipsFAQsWarningsDosageInteractionsCostContraindicationsAlternativesLatest newsReferencesPricesMedicare
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What is Cycloserine (Seromycin)?

What is Cycloserine (Seromycin) used for?

How Cycloserine (Seromycin) works

Cycloserine (Seromycin) is an antibiotic. It kills bacteria by preventing them from making their cell walls, which are important "shields" that bacteria use to protect themselves.

Are you looking for information on cyclosporine non-modified (Sandimmune) or cyclosporine modified (Neoral) instead?

Drug Facts

Common BrandsSeromycin
Drug ClassAntitubercular agent
Controlled Substance ClassificationNot a controlled medication
Generic StatusLower-cost generic available
AvailabilityPrescription only
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What are the side effects of Cycloserine (Seromycin)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Side effects are more likely to happen at doses greater than 500 mg per day.
  • Sleepiness
  • Headache
  • Tremor (shakiness)
  • Trouble speaking or slurred speech
  • Feeling like your surroundings are spinning (vertigo)
  • Confusion
  • Memory problems
  • Changes in mood, thoughts, or behaviors

Other Side Effects

  • Skin rash

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.
  • Seizures
  • Heart failure: shortness of breath, swelling in the stomach or legs, sudden weight gain, tiredness, dizziness
  • Allergic reaction: rash, hives, trouble breathing, swelling of the face

Source: DailyMed

The following side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Anxiety

confusion

dizziness

drowsiness

increased irritability

increased restlessness

mental depression

muscle twitching or trembling

nervousness

nightmares

other mood or mental changes

speech problems

thoughts of suicide

Less common

Convulsions (seizures)

numbness, tingling, burning pain, or weakness in the hands or feet

skin rash

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Headache

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

pros-and-cons

Pros and cons of Cycloserine (Seromycin)

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Pros

Might be useful for hard-to-treat TB infections

Doesn't typically cause liver damage like most anti-TB antibiotics

Fewer drug interactions than other anti-TB antibiotics

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Cons

Not a first-choice option for treating infections

Requires frequent blood tests to monitor medication levels in the body

Not a good option for people who have seizures or mental health problems

pharmacist-tips

Pharmacist tips for Cycloserine (Seromycin)

pharmacist

  • Before you start taking cycloserine (Seromycin), make sure your provider and pharmacist have a full list of your medications and medical history. Certain medical conditions and medications can raise your risk of nerve problems and unwanted side effects.

    • Cycloserine (Seromycin) might make you feel dizzy and tired. Avoid driving and doing tasks that require you to be alert until you know how the medication affects you.

      • Don't drink alcohol while you're taking cycloserine (Seromycin). This medication has a risk of seizures at higher doses, and drinking a lot of alcohol can raise your risk even more.

        • It's important to remember to take all your doses of cycloserine (Seromycin) on time. Missing or skipping doses can make the antibiotic work less well against the bacteria, which can then make the infection harder to treat. Take cycloserine (Seromycin) exactly as prescribed, finish your treatment course, and don't stop taking the antibiotic unless instructed by your provider.

          • Cycloserine (Seromycin) is usually prescribed with other antibiotics when it's used to treat TB to prevent drug resistance. Make sure you know which medications are part of your anti-TB treatment plan so you can start them all at the same time.

            faqs

            Frequently asked questions about Cycloserine (Seromycin)

            Do penicillin and cycloserine (Seromycin) do the same thing?
            Penicillin and cycloserine (Seromycin) are both antibiotics that fight certain bacterial infections. They both stop bacteria from making strong cell walls, which bacteria use to "shield" themselves from harm. But how exactly the two medications do this is a little different — they block different proteins that bacteria use to make their cell walls.
            How long can you take cycloserine (Seromycin) for?
            There isn't a set amount of time that you can take cycloserine (Seromycin) for. But if you're taking the antibiotic for TB, treatment typically lasts for many months. Your provider will determine how long you need to take cycloserine (Seromycin) for based on how your body responds to treatment and whether you have side effects from the medication (e.g., nervous system problems). It's important to take cycloserine (Seromycin) and your other anti-TB medications exactly as prescribed. Don't stop taking them unless instructed by your provider. This helps prevent drug-resistant TB, which can be even harder to treat. Speak with your provider about how long you need to take cycloserine (Seromycin) for.
            Can cycloserine (Seromycin) cause psychosis?
            It's possible for people who take cycloserine (Seromycin) to develop psychosis, which include hallucinations and delusions. The risk for psychosis is higher if you're taking this antibiotic at doses higher than 500 mg per day. Speak with your provider if you have concerns about this side effect. And get medical help as soon as possible if you or your loved ones notice that you start hearing or seeing things that aren't real or having delusional thinking. Your dose might need to be lowered or your treatment plan might need to change.
            Can I drink alcohol with cycloserine (Seromycin)?
            It's best to avoid alcohol while you're taking cycloserine (Seromycin). This medication can cause serious side effects, like seizures. And the risk for seizures happening while you're taking this medication is higher if you drink large amounts of alcohol on a regular basis. Speak with your provider about your drinking habits while you're taking cycloserine (Seromycin). Your provider can discuss with you about ways to stop drinking altogether.
            What is the difference between cyclosporine and cycloserine (Seromycin)?
            While cyclosporine and cycloserine (Seromycin) sound alike, they're two completely different medications. Cyclosporine is used to treat or prevent rejection after someone gets an organ transplant; it works by lowering the activity of the immune system. On the other hand, cycloserine (Seromycin) is an antibiotic that helps fight tuberculosis (TB) and urinary tract infections (UTIs) that are very hard to treat; it works by killing bacteria.
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            What are the risks and warnings for Cycloserine (Seromycin)?

            Cycloserine (Seromycin) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

            risk-warning

            Nervous system problems

            • Risk factors: Taking over 500 mg of cycloserine (Seromycin) per day | Heavy alcohol use | Kidney problems | Also taking Trecator (ethionamide) or isoniazid

              Cycloserine (Seromycin) can cause sleepiness, headache, tremor, balance problems, muscle weakness, and confusion. This medication can also cause more serious problems like seizures, depression, anxiety, psychosis, and other changes in mood or behavior.

              These problems are more likely to happen if you're taking cycloserine (Seromycin) at doses higher than 500 mg per day. You're also at risk if you have kidney problems; the body can't get rid of the medication properly from the system and the medication builds up in the body. In addition, drinking large amounts of alcohol also raises the risk for seizures.

              You'll need to get lab work done often so your provider can check the medication levels in your blood and monitor you for side effects. Call your provider if you have any symptoms of nervous system problems. Get medical help right away if you have a seizure while you're taking this medication.

              risk-warning

              Heart failure when used at very high doses

              Some people who took cycloserine (Seromycin) at very high doses (1 to 1.5 grams per day) suddenly had heart failure. This condition happens when the heart isn't able to pump as well as it should. Contact your provider right away if you notice symptoms of heart failure, such as shortness of breath that's worse with activity or when lying down, swelling in the stomach or legs, sudden weight gain, tiredness, or dizziness.

              risk-warning

              Low vitamin B12 and folic acid levels

              Some people who took cycloserine (Seromycin) developed low vitamin B12 levels and low folic acid levels. This can lead to anemia (low red blood cell counts). Your provider will check your vitamin levels and blood cell counts during treatment. Make sure to let your provider know if you notice any symptoms of anemia, such as tiredness, pale skin, shortness of breath, or lightheadedness.

              dosage

              Cycloserine (Seromycin) dosage forms

              The average cost for 30 capsules of 250mg of Cycloserine (Seromycin) is $368.04 with a free GoodRx coupon. This is 86.09% off the average retail price of $2645.27.
              capsule
              Capsule
              DosageQuantityPrice as low asPrice per unit
              250mg30 capsules$368.04$12.27

              Typical dosing for Cycloserine (Seromycin)

              The typical starting dose is 250 mg by mouth every 12 hours for the first 2 weeks. Your provider will adjust your dose based on the levels of cycloserine (Seromycin) in your blood. The usual dose ranges from 500 mg to 1 gram per day, separated into smaller doses throughout the day.

              interactions

              Interactions between Cycloserine (Seromycin) and other drugs

              Cycloserine (Seromycin) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Cycloserine (Seromycin). Please note that only the generic name of each medication is listed below.

              More on Cycloserine (Seromycin) interactions

              Health: Skin Health: GettyImages 1251349908

              Alcohol and Antibiotics: Is Mixing Them Really That Dangerous?

              Written by Megan N. Freeland, PharmD, RPh

              Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

              • Ethionamide
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              contraindications-icon

              Cycloserine (Seromycin) contraindications

              Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Cycloserine (Seromycin) will not be safe for you to take.

              • Seizure condition (epilepsy)

              • Depression, severe anxiety, or psychosis

              • Severe kidney problems

              • Heavy alcohol use

              alternatives

              What are alternatives to Cycloserine (Seromycin)?

              There are a number of medications that your doctor can prescribe in place of Cycloserine (Seromycin). Compare a few possible alternatives below.
              Cycloserine (Seromycin)
              Used for:
              $368.04 Lowest GoodRx priceView Prices
              Sirturo (bedaquiline)
              Used for:

              • Tuberculosis (TB) lung infection that is resistant (doesn't respond to) to other anti-TB antibiotics

              $3829.46 Lowest GoodRx priceView Prices
              Trecator (ethionamide)
              Used for:

              • Tuberculosis (TB) that is resistant (doesn't respond to) to first-choice anti-TB antibiotics (e.g., isoniazid or rifampin (Rifadin))

              • TB infection in people who can't take other anti-TB antibiotics

              $179.00 Lowest GoodRx priceView Prices

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              References

              Best studies we found

              Centers for Disease Control and Prevention. (2016). Adverse events during treatment.

              Centers for Disease Control and Prevention. (2022). About antimicrobial resistance.

              Centers for Disease Control and Prevention. (2022). Drug resistant TB.

              View All References (7)

              Centers for Disease Control and Prevention. (2023). Treatment for TB disease.

              Dr. Reddy’s Laboratories, Inc. (2023). Cycloserine capsule [package insert]. DailyMed.

              Kiran, C., et al. (2009). Understanding delusions. Industrial Psychiatry Journal.

              Nahid, P., et al. (2019). Treatment of drug-resistant tuberculosis. An official ATS/CDC/ERS/IDSA Clinical Practice Guideline. American Journal of Respiratory and Critical Care Medicine.

              Schacter, S. C. (n.d.). Alcohol as a seizure trigger. Epilepsy Foundation.

              Schaumburg, H. H., et al. (2000). Cycloserine. Experimental and Clinical Neurotoxicology (Second Edition).

              Tweed, C. D., et al. (2018). Liver toxicity associated with tuberculosis chemotherapy in the REMoxTB study. BioMed Central Medicine.

              GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.
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