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Cycloserine (Systemic)

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Cycloserine (Systemic)

US Brand Names

• Seromycin


Cycloserine (sye-kloe-SER-een) belongs to the family of medicines called antibiotics. It is used to treat tuberculosis (TB). When cycloserine is used for TB, it is given with other medicines for TB. Cycloserine may also be used for other conditions as determined by your doctor.

To help clear up your tuberculosis (TB) completely, you must keep taking this medicine for the full time of treatment, even if you begin to feel better. This is very important. It is also important that you do not miss any doses .

Cycloserine is available only with your doctor's prescription, in the following dosage form:


    • Capsules (U.S.)

Special Considerations

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For cycloserine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to cycloserine. Also, tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.


Cycloserine has not been shown to cause birth defects or other problems in humans.


Cycloserine passes into the breast milk. However, cycloserine has not been reported to cause problems in nursing babies.


Although there is no specific information comparing use of cycloserine in children with use in other age groups, this medicine is not expected to cause different side effects or problems in children than it does in adults.

Older adults

Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of cycloserine in the elderly with use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking cycloserine, it is especially important that your health care professional know if you are taking the following:

    • Ethionamide (e.g., Trecator-SC)-Ethionamide may increase the risk of nervous system side effects, especially seizures

Other medical problems

The presence of other medical problems may affect the use of cycloserine. Make sure you tell your doctor if you have any other medical problems, especially:

    • Alcohol abuse (or history of) or

    • Convulsive disorders such as seizures or epilepsy-Cycloserine may increase the risk of seizures in patients who drink alcohol or have a history of seizures

    • Kidney disease-Cycloserine is removed from the body through the kidneys, and patients with kidney disease may need an adjustment in dose or the medicine may need to be discontinued

    • Mental disorders such as mental depression, psychosis, or severe anxiety-Cycloserine may cause anxiety, mental depression, or psychosis


Cycloserine may be taken after meals if it upsets your stomach.

To help clear up your infection completely, it is very important that you keep taking this medicine for the full time of treatment , even if you begin to feel better after a few weeks. If you are taking this medicine for TB, you may have to take it every day for as long as 1 to 2 years or more. If you stop taking this medicine too soon, your symptoms may return.

This medicine works best when there is a constant amount in the blood or urine. To help keep the amount constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times day and night . For example, if you are to take 2 doses a day, the doses should be spaced about 12 hours apart. If this interferes with your sleep or other daily activities, or if you need help in planning the best times to take your medicine, check with your health care professional.


The dose of cycloserine will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of cycloserine. If your dose is different, do not change it unless your doctor tells you to do so.

    • For the oral dosage form (capsules):

      o For treatment of tuberculosis:

        Adults and teenagers-250 milligrams (mg) two times a day to start. Your doctor may slowly increase your dose up to 250 mg three or four times a day. This medicine must be taken along with other medicines to treat tuberculosis.

        Children-Use and dose must be determined by your doctor. Doses of 10 to 20 mg per kilogram (4.5 to 9.1 mg per pound) of body weight per day have been used. This medicine must be taken along with other medicines to treat tuberculosis.

Missed dose

If you do miss a dose of this medicine, take it as soon as possible. This will help to keep a constant amount of medicine in the blood or urine. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


To store this medicine:

    • Keep out of the reach of children.

    • Store away from heat and direct light.

    • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.

    • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.


It is very important that your doctor check your progress at regular visits.

If your symptoms do not improve within 2 to 3 weeks, or if they become worse, check with your doctor.

If cycloserine causes you to feel very depressed or to have thoughts of suicide, check with your doctor immediately . Your doctor will probably want to change your medicine.

This medicine may cause some people to become dizzy, drowsy, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert . If these reactions are especially bothersome, check with your doctor.

Some of cycloserine's side effects (for example, convulsions [seizures]) may be more likely to occur if you drink alcoholic beverages regularly while you are taking this medicine. Therefore, you should not drink alcoholic beverages while you are taking this medicine .

Side Effects

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.

Other 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. However, check with your doctor if the following side effect continues or is bothersome:

More common


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

Additional Information

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, ethambutol is used in certain patients with the following medical condition:

    • Atypical mycobacterial infections, such as Mycobacterium avium complex (MAC)

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for this use.

May 02, 1994

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