Sulfamethoxazole and trimethoprim, specifically the trimethoprim component, can interfere with a serum methotrexate assay as determined by the competitive binding protein technique (CBPA) when a bacterial dihydrofolate reductase is used as the binding protein.

8. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur.

Available at: http://www.fda.gov/cder/ob/. Sulfamethoxazole and Trimethoprim Oral Suspension is a synthetic antibacterial combination product. It's a pink liquid antibiotic. Because these reactions were reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to drug exposure:The amount of a single dose of sulfamethoxazole and trimethoprim that is either associated with symptoms of overdosage or is likely to be life-threatening has not been reported. Site users seeking medical advice about their specific situation should consult with their own physician. Standard sulfamethoxazole/trimethoprim powder should provide the following range of values:Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. This medication is a combination of two antibiotics: sulfamethoxazole and trimethoprim. The mean maximum serum trimethoprim concentration was higher and mean renal clearance of trimethoprim was lower in geriatric subjects compared with younger subjects (see The most common adverse effects are gastrointestinal disturbances (nausea, vomiting, anorexia) and allergic skin reactions (such as rash and urticaria). For this medicine, the following should be considered:Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Talk with your doctor if you have concerns about this.Do not use this medicine for Pneumocystis jiroveci pneumonia (PCP) if you are also using leucovorin. Montvale (NJ): Thomson Healthcare; 2007. These may be symptoms of a serious intestinal infection.This medicine may cause serious allergic reactions, including anaphylaxis.
However, elderly patients are more likely to have a folate deficiency, age-related kidney or liver problems, and may be more likely to experience unwanted side effects (eg, severe skin rash, increased potassium in the body, or problems with blood clotting or the immune system).

Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by sulfamethoxazole and trimethoprim oral suspension or other antibacterial drugs in the future.Patients should be instructed to maintain an adequate fluid intake in order to prevent crystalluria and stone formation.Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. At one point, Sulfatrim tablets and adults Sulfatrim suspension were available, but are no longer being made. Continue Learning about Antibiotic 6 Ailments That Call for an Antibiotic When it comes to a lingering case of the sniffles, your first instinct may still be to run to … In two studies in rats, no teratology was observed when 512 mg/kg of sulfamethoxazole was used in combination with 128 mg/kg of trimethoprim.