FLUCYTOSINE (Systemic)
Some commonly used brand names are:
In the U.S.?
In Canada?
Other commonly used names are 5-fluorocytosine and 5-FC.
Category
Description
Flucytosine (floo-SYE-toe-seen) belongs to the groupof medicines called antifungals. It is used to treat certain fungus infections.
Flucytosine is available only with your doctor's prescription, in the followingdosage form:
Oral- Capsules (U.S. and Canada)
Before Using This Medicine
In deciding to use a medicine,the risks of taking the medicine must be weighed against the good it willdo. This is a decision you and your doctor will make. For flucytosine, thefollowing should be considered:
Allergies?Tell your doctor if you have ever had any unusual orallergic reaction to flucytosine. Also tell your health care professionalif you are allergic to any other substances, such as foods, preservatives,or dyes.
Pregnancy?Flucytosine has not been reported to cause birthdefects or other problems in humans. However, studies in rats have shown thatflucytosine causes birth defects.
Breast-feeding?It is not known if flucytosine passes into breastmilk. Discuss with your doctor whether or not you should discontinue breast-feedingwhile using this medicine.
Children?Although there is no specific information comparinguse of flucytosine in children with use in other age groups, this medicineis not expected to cause different side effects or problems in children thanit does in adults.
Older adults?Many medicines have not been studied specificallyin older people. Therefore, it may not be known whether they work exactlythe same way they do in younger adults. Although there is no specific informationcomparing use of flucytosine in the elderly with use in other age groups,this medicine is not expected to cause different side effects or problemsin older people than it does in younger adults.
Other medicines?Although certain medicines should not be usedtogether at all, in other cases two different medicines may be used togethereven if an interaction might occur. In these cases, your doctor may want tochange the dose, or other precautions may be necessary. When you are takingflucytosine, it is especially important that your health care professionalknows if you are taking any of the following:
- Amphotericin B by injection (e.g., Fungizone) or
- Antineoplastics (cancer medicine) or
- Antithyroid agents (medicine for overactive thyroid) or
- Azathioprine (e.g., Imuran) or
- Chloramphenicol (e.g., Chloromycetin) or
- Colchicine or
- Cyclophosphamide (e.g., Cytoxan) or
- Ganciclovir (e.g., Cytovene) or
- Interferon (e.g., Intron A, Roferon-A) or
- Mercaptopurine (e.g., Purinethol) or
- Methotrexate (e.g., Mexate) or
- Plicamycin (e.g., Mithracin) or
- Zidovudine (e.g., AZT, Retrovir) or
- X-ray treatment?Use of flucytosine with any of these medicinesmay increase the chance for side effects of the blood
Other medical problems?The presence of other medicalproblems may affect the use of flucytosine. Make sure you tell your doctorif you have any other medical problems, especially:
- Blood disease?Flucytosine may cause blood problems
- Kidney disease?Patients with kidney disease may have an increasedchance of side effects
- Liver disease?Flucytosine may cause liver side effects
Proper Use of This Medicine
In some patientsthis medicine may cause nausea or vomiting. If you are taking more than 1capsule for each dose, you may space them out over a period of 15 minutesto help lessen the nausea or vomiting. If this does not help or if you haveany questions, check with your doctor.
To help clear up your infection completely, keep takingthis medicine for the full time of treatment, even if you begin tofeel better after a few days. Do not miss any doses.
Dosing?The dose of flucytosine will be different fordifferent patients. Follow your doctor's orders or thedirections on the label. The following information includes only theaverage doses of flucytosine. If your dose is different,do not change it unless your doctor tells you to do so.
- For oral dosage form (capsules):
- For fungus infections:
- Adults and children?Dose is based on body weight. The usualdose is 12.5 to 37.5 milligrams (mg) per kilogram (kg) (5.7 to 17 mg per pound)of body weight every six hours.
Missed dose?If you miss a dose of this medicine, take it assoon as possible. However, if it is almost time for your next dose, skip themissed dose and go back to your regular dosing schedule. Do not double doses.
Storage?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 otherdamp places. Heat or moisture may cause the medicine to break down.
- Do not keep outdated medicine or medicine no longer needed. Be surethat any discarded medicine is out of the reach of children.
Precautions While Using This Medicine
Yourdoctor should check your progress at regular visits to make sure that thismedicine does not cause unwanted effects.
Flucytosine may cause blood problems. These problems may result in a greaterchance of infection, slow healing, and bleeding of the gums. Therefore, youshould be careful when using regular toothbrushes, dental floss, and toothpicks.Dental work, whenever possible, should be done before you begin taking thismedicine or delayed until your blood counts have returned to normal. Checkwith your medical doctor or dentist if you have any questions about properoral hygiene (mouth care) during treatment.
Flucytosine may cause your skin to be more sensitive to sunlight than itis normally. Exposure to sunlight, even for brief periods of time, may causeskin rash, itching, redness, or other discoloration of the skin, or a severesunburn. When you begin taking this medicine:
- Stay out of direct sunlight, especially between the hours of 10:00a.m. and 3:00 p.m., if possible.
- Wear protective clothing, including a hat. Also, wear sunglasses.
- Apply a sun block product that has a skin protection factor (SPF)of at least 15. Some patients may require a product with a higher SPF number,especially if they have a fair complexion. If you have any questions aboutthis, check with your health care professional.
- Apply a sun block lipstick that has an SPF of at least 15 to protectyour lips.
- Do not use a sunlamp or tanning bed or booth.
If you have a severe reaction from the sun, check withyour doctor.
This medicine may also cause some people to become dizzy, lightheaded,drowsy, or less alert than they are normally. Make sureyou know how you react to this medicine before you drive, use machines, ordo anything else that could be dangerous if you are dizzy or are not alert. If these reactions are especially bothersome, check with your doctor.
Side Effects of This Medicine
Along with its needed effects, a medicine maycause 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 ofthe following side effects occur:
Other side effects may occur that usually donot need medical attention. These side effects may go away during treatmentas your body adjusts to the medicine. However, check with your doctor if anyof the following side effects continue or are bothersome:
Other side effects not listed above may also occur in some patients. Ifyou notice any other effects, check with your doctor.
Revised: 03/08/2000
