Fidaxomicin is a new macrocyclic antibiotic with a narrow spectrum. It inhibits bacterial RNA polymerase and kills C difficile while having little impact on normal intestinal flora. On January 10, 2011, the US FDA granted orphan drug designation to all formulations of Fidaxomicin for the treatment of C difficile infections in paediatric patients. Fidaxomicin is bactericidal against Clostridium difficile and has a long post-antibiotic effect. Despite the fact that this medication has an orphan designation for paediatrics, all available pharmacokinetic and pharmacodynamic data were from subjects over the age of 18.Fidaxomicin is a bactericidal antibiotic with a long post-antibiotic effect against Clostridium difficile. Despite the fact that this medication is designated as orphan for paediatrics, all available pharmacokinetic and pharmacodynamic data were from subjects over the age of 18. Fidaxomicin's MIC90 against Clostridium difficile ranges from 0.0078-0.25 mcg/ml. Fidaxomicin has a poor absorption rate. Patients receiving fidaxomicin had the highest peak plasma concentration of 0.191 mcg/ml. Fidaxomicin faeces are extremely high after oral administration. In the 100, 200, and 400 mg/day groups, the average faecal concentrations in C difficile patients were 255.6 mcg/g, 441.7 mcg/g, and 1443.3 mcg/g, respectively. The average faecal concentration at 400 mg/day was 5700 times greater than the highest MIC90 of fidaxomicin against C difficile. Fidaxomicin 200 mg twice day and vancomycin 125 mg four times daily were contrasted for 10 days in a phase III clinical research. No patients under the age of 18 took part in the study, and only two patients were under 18. Fidaxomicin's clinical cure rates were comparable to those of vancomycin. Patients in the fidaxomicin group saw fewer recurrences than those in the vancomycin group when they had non-North American Pulsed Field type 1 strains of the infection. Both treatments' side effects were comparable. The majority of patients only had minor gastrointestinal problems. Vancomycin and metronidazole are both effective treatment alternatives to fidaxomicin, particularly for individuals who have C difficile infections that keep coming back. Systemic side effects are uncommon in patients, which increases compliance. The dose of fidaxomicin is expected to be 200 mg given orally twice a day for patients 16 years and older. Additional clinical trials in pediatric patients are needed before therapeutic recommendations can be made in this population. KEYWORDS: Fidaxomicin; Pediatrics; Clostridium difficile; Phar-macokinetic, pharmacodynamics.