Sulfonamides and Phenazopyridine (Systemic)

Before Using This Medicine

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 sulfonamides and phenazopyridine, the following should be considered:

Allergies - Tell your doctor if you have ever had any unusual or allergic reaction to any of the sulfa medicines, furosemide (e.g., Lasix) or thiazide diuretics (water pills), oral antidiabetics (diabetes medicine you take by mouth), glaucoma medicine you take by mouth (for example, acetazolamide [e.g., Diamox], dichlorphenamide [e.g., Daranide], methazolamide [e.g., Neptazane]), or phenazopyridine (e.g., Pyridium). Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy - Studies have not been done in humans. Studies in mice, rats, and rabbits have shown that some sulfonamides cause birth defects, including cleft palate and bone problems. In addition, sulfa medicines may cause liver problems in newborn infants. Therefore, use is not recommended during pregnancy. Phenazopyridine has not been shown to cause birth defects in animal studies.

Breast-feeding - Sulfonamides pass into the breast milk. This medicine is not recommended for use during breast-feeding. It may cause liver problems, anemia, and other unwanted effects in nursing babies, especially those with glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Children - This medicine has been tested in a limited number of children 12 years of age or older. In effective doses, the medicine has not been shown to cause different side effects or problems in children than it does in adults.

Older adults - Elderly people are especially sensitive to the effects of sulfonamides. Severe skin problems and blood problems may be more likely to occur in the elderly. These problems may also be more likely to occur in patients who are taking diuretics (water pills) along with this medicine.

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 sulfonamides and phenazopyridine, it is especially important that your health care professional know if you are taking any of the following:

• Acetaminophen (e.g., Tylenol) (with long-term, high-dose use) or
• Amiodarone (e.g., Cordarone) or
• Anabolic steroids (nandrolone [e.g., Anabolin], oxandrolone [e.g., Anavar], oxymetholone [e.g., Anadrol], stanozolol [e.g., Winstrol]) or
• Androgens (male hormones) or
• Antithyroid agents (medicine for overactive thyroid) or
• Carbamazepine (e.g., Tegretol) or
• Carmustine (e.g., BiCNU) or
• Chloroquine (e.g., Aralen) or
• Dantrolene (e.g., Dantrium) or
• Daunorubicin (e.g., Cerubidine) or
• Disulfiram (e.g., Antabuse) or
• Divalproex (e.g., Depakote) or
• Estrogens (female hormones) or
• Etretinate (e.g., Tegison) or
• Gold salts (medicine for arthritis) or
• Hydroxychloroquine (e.g., Plaquenil) or
• Mercaptopurine (e.g., Purinethol) or
• Naltrexone (e.g., Trexan) (with long-term, high-dose use) or
• Oral contraceptives (birth control pills) containing estrogen or
• Other anti-infectives by mouth or by injection (medicine for infection) or
• Phenothiazines (acetophenazine [e.g., Tindal], chlorpromazine [e.g., Thorazine], fluphenazine [e.g., Prolixin], mesoridazine [e.g., Serentil], perphenazine [e.g., Trilafon], prochlorperazine [e.g., Compazine], promazine [e.g., Sparine], promethazine [e.g., Phenergan], thioridazine [e.g., Mellaril], trifluoperazine [e.g., Stelazine], triflupromazine [e.g., Vesprin], trimeprazine [e.g., Temaril]) or
• Plicamycin (e.g., Mithracin) or
• Valproic acid (e.g., Depakene) - Use of sulfonamides and phenazopyridine combination with these medicines may increase the chance of side effects affecting the liver

• Acetohydroxamic acid (e.g., Lithostat) or
• Dapsone or
• Furazolidone (e.g., Furoxone) or
• Nitrofurantoin (e.g., Furadantin) or
• Primaquine or
• Procainamide (e.g., Pronestyl) or
• Quinidine (e.g., Quinidex) or
• Quinine (e.g., Quinamm) or
• Sulfoxone (e.g., Diasone) or
• Vitamin K (e.g., AquaMEPHYTON, Synkayvite) - Use of sulfonamides and phenazopyridine combination with these medicines may increase the chance of side effects affecting the blood

• Anticoagulants (blood thinners) or
• Ethotoin (e.g., Peganone) or
• Heparin or
• Mephenytoin (e.g., Mesantoin) - Use of sulfonamides and phenazopyridine combination with these medicines may increase the chance of side effects of these medicines

• Antidiabetics, oral (diabetes medicine you take by mouth) - Use of oral antidiabetics with sulfonamides and phenazopyridine combination may increase the chance of side effects affecting the blood and/or the side effects of oral antidiabetics

• Methenamine (e.g., Mandelamine) or
• Methenamine-containing medicines (e.g., Urised) - Use of these medicines with sulfonamides and phenazopyridine combination may increase the chance of side effects of the sulfonamides

• Methotrexate (e.g., Mexate) - Use of methotrexate with sulfonamides and phenazopyridine combination may increase the chance of side effects affecting the liver and/or the side effects of methotrexate

• Methyldopa (e.g., Aldomet) - Use of methyldopa with sulfonamides and phenazopyridine combination may increase the chance of side effects affecting the liver and/or the blood

• Phenytoin (e.g., Dilantin) - Use of phenytoin with sulfonamides and phenazopyridine combination may increase the chance of side effects affecting the liver and/or the side effects of phenytoin

Other medical problems - The presence of other medical problems may affect the use of sulfonamides and phenazopyridine. Make sure you tell your doctor if you have any other medical problems, especially:

• Anemia or other blood problems or
• Glucose-6-phosphate dehydrogenase deficiency (lack of G6PD enzyme) - Patients with these problems may have an increase in side effects affecting the blood

• Hepatitis or other liver disease or
• Kidney disease - Patients with kidney disease or liver disease may have an increased chance of side effects

• Porphyria - Use of sulfonamides may bring on an attack of porphyria