The usual dose in adults and children over 12 years of age is 2 Sulfatrim tablets or 1 Sulfatrim DS tablet twice daily. The maximum dose is 3 Sulfatrim tablets or 1.5 Sulfatrim DS tablets twice daily in severe infections.

Sulfatrim tablets are a combination of two antibiotics called trimethoprim and sulfamethoxazole. These antibiotics work together by inhibiting two critical steps in the production of bacterial folic acid. The resulting decrease in folic acid interferes with the production of genetic building blocks and proteins of bacteria. The effectiveness of Sulfatrim depends on factors such as dose, concentration in the blood as well as other body fluids and tissue, and susceptibility of the organism. Infections caused by bacteria that are not sensitive to Sulfatrim will not show improvement after taking this medication.

Along with its needed effects, Sulfatrim may cause some unwanted or undesirable effects. Generally, Sulfatrim is well tolerated and many people will not experience unwanted effects. The frequency and severity of these effects is dependant on many factors including dose, duration of therapy and individual susceptibility. Possible unwanted effects include:

• diarrhea
• dizziness
• headache
• loss of appetite
• mouth sores or swelling of the tongue
• nausea or vomiting
• tiredness
• Increased sensitivity of skin to sunlight

Uncommon:

• joint or muscle pain
• difficulty in swallowing
• pale skin
• sore throat and fever

Allergic reactions can occur with Sulfatrim use. People with a history of allergy, asthma, hay fever or hives seem to be more susceptible to these reactions. The reaction can be immediate and severe. Allergic symptoms include wheezing, hives, itching, swelling, spasms in the throat and breathing tubes, joint and muscle pain, difficulty breathing, fever and skin rashes. Nausea and vomiting are not symptoms of an allergic reaction.
Taking the antibiotic repeatedly or for prolonged periods may result in bacterial or fungal overgrowth which can lead to a second infection. When this occurs, the Sulfatrim may need to be stopped and another antibiotic prescribed to treat the new infection.
Elderly people may be at an increased risk for side effects, especially when complicating conditions exist (such as kidney or liver disease).
Drink enough fluids (e.g. water) to increase urine flow.
Sulfatrim may cause your skin to be more sensitive to sunlight. Exposure to sunlight, even for brief periods of time, may cause skin rash, itching, redness or severe sunburn. Stay out of direct sunlight, wear protective clothing and apply sun block. Do not use a sunlamp or tanning bed while on this medication.

Drug Interactions: It is important to tell your doctor and pharmacist of any prescription or over-the-counter medications you are taking. In some cases, the dose of one or both drugs may need to be altered or another drug may be prescribed. The following drugs or drug classes have been known to interact with Sulfatrim:

• oral contraceptives (e.g. Triphasil®)
• warfarin (e.g. Coumadin®)
• thiazide diuretics (e.g. hydrochlorothiazide®)
• phenytoin (e.g. Dilantin®)
• methotrexate
• digoxin
• cyclosporine (e.g. Neoral®)

Use is not recommended in the following situations:

• allergy to trimethoprim or sulfonamides
• megaloblastic anemia due to folate deficiency
• liver disease
• blood disorders
• infants less than 2 months of age
• pregnancy and breastfeeding

Caution is recommended in the following situations:

• asthma
• elderly patients (especially with liver or kidney disease)
• liver disease
• kidney disease
• low folic acid levels

Use in pregnancy: Use is not recommended.  Consult your doctor or pharmacist if you suspect you are pregnant.
Use while breast-feeding: Use is not recommended.  Consult your doctor or pharmacist before you begin breast-feeding.