Primaxin Drug Information

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adult Patients During clinical investigations 1,723 patients were treated with PRIMAXIN. Table 4 shows the incidence of adverse reactions reported during the clinical investigations of adult patients treated with PRIMAXIN. Table 4: Incidence (%) Adverse reactions with an incidence ≥0.2% of PRIMAXIN-treated adult patients. of Adverse Reactions Reported During Clinical Investigations of Adult Patients Treated with PRIMAXIN Body System Adverse Reactions Frequency (%) Local Administration site Phlebitis/thrombophlebitis 3.1% Pain at the injection site 0.7% Erythema at the injection site 0.4% Vein induration 0.2% Gastrointestinal Nausea 2.0% Diarrhea 1.8% Vomiting 1.5% Skin Rash 0.9% Pruritus 0.3% Urticaria 0.2% Vascular Hypotension 0.4% Body as a Whole Fever 0.5% Nervous system Seizures 0.4% Dizziness 0.3% Somnolence 0.2% Additional adverse reactions reported in less than 0.2% of the patients or reported since the drug was marketed are listed within each body system in order of decreasing severity . Table 5: Additional Adverse Reactions Occurring in Less than 0.2% of Adult Patients Listed within Each Body System in Order of Decreasing Severity Body System Adverse Reactions Gastrointestinal Pseudomembranous Colitis (the onset of Pseudomembranous colitis symptoms), Hemorrhagic Colitis Gastroenteritis Abdominal Pain Glossitis Tongue Papillar Hypertrophy Heartburn Pharyngeal Pain Increased Salivation CNS Encephalopathy Confusion Myoclonus Paresthesia Vertigo Headache Special Senses Hearing Loss Tinnitus Respiratory Chest Discomfort Dyspnea Hyperventilation Thoracic Spine Pain Cardiovascular Palpitations Tachycardia Skin Erythema Multiforme Angioneurotic Edema Flushing Cyanosis Hyperhidrosis Skin Texture Changes Candidiasis Pruritus Vulvae Local Administration site Infused vein infection Body as a Whole Polyarthralgia Asthenia/Weakness Renal Oliguria/Anuria Polyuria Adverse Laboratory Changes The following adverse laboratory changes were reported during clinical trials: Hepatic: Increased alanine aminotransferase (ALT or SGPT), aspartate aminotransferase (AST or SGOT), alkaline phosphatase, bilirubin, and lactate dehydrogenase (LDH) Hemic: Increased eosinophils, positive Coombs test, increased WBC, increased platelets, decreased hemoglobin and hematocrit, increased monocytes, abnormal prothrombin time, increased lymphocytes, increased basophils Electrolytes: Decreased serum sodium, increased potassium, increased chloride Renal: Increased BUN, creatinine Urinalysis: Presence of urine protein, urine red blood cells, urine white blood cells, urine casts, urine bilirubin, and urine urobilinogen. Pediatric Patients Table 6: Incidence (%) Adverse reactions that occurred in >1% of PRIMAXIN-treated pediatric patients (greater than or equal to 3 months of age) of Adverse Reactions Reported During Clinical Investigations of Pediatric Patients Greater Than or Equal to 3 Months of Age Treated with PRIMAXIN Body System Adverse Reactions Frequency (%) Local Administration Site Phlebitis 2.2% Intravenous Site Irritation 1.1% Gastrointestinal Diarrhea 3.9% Gastroenteritis 1.1% Vomiting 1.1% Skin Rash 2.2% Renal Urine Discoloration 1.1% Table 7: Incidence (%) Adverse reactions that occurred in >1% of PRIMAXIN-treated pediatric patients (neonates to 3 months of age) of Adverse Reactions Reported During Clinical Investigations of Pediatric Patients Neonates to 3 Months of Age Treated with PRIMAXIN Body System Adverse Reactions Frequency (%) Gastrointestinal Diarrhea 3% CNS Convulsions 5.9% Cardiovascular Tachycardia 1.5% Skin Rash 1.5% Body as a Whole Oral Candidiasis 1.5% Renal Oliguria/Anuria 2.2% Adverse Laboratory Changes The following adverse laboratory changes were reported in studies of 178 pediatric patients 3 months of age: increased AST (SGOT), decreased hemoglobin/hematocrit, increased platelets, increased eosinophils, increased ALT (SGPT), increased urine protein, decreased neutrophils.

The following adverse laboratory changes were reported in studies of 135 patients (neonates to 3 months of age): increased eosinophils, increased AST (SGPT), increased serum creatinine, increased/decreased platelet count, increased/decreased bilirubin, increased ALT (SGPT), increased alkaline phosphatase, increased/decreased hematocrit.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of PRIMAXIN. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Table 8: Adverse Reactions Identified During Post Approval Use of PRIMAXIN Body System Adverse Reactions Gastrointestinal Hepatitis (including fulminant hepatitis) Hepatic failure Jaundice Staining of the teeth and/or tongue Hematologic Pancytopenia Bone marrow depression Thrombocytopenia Neutropenia Leukopenia Hemolytic anemia CNS Tremor Psychic disturbances including hallucinations Dyskinesia Agitation Special Senses Taste perversion Skin Stevens-Johnson syndrome Toxic epidermal necrolysis Body as a whole Drug fever Renal Acute renal failure Urine discoloration Adverse Laboratory Changes Adverse laboratory changes reported since the drug was marketed were: Hematologic: agranulocytosis. Examination of published literature and spontaneous adverse reactions reports suggested a similar spectrum of adverse reactions in adult and pediatric patients.

Ganciclovir Generalized seizures have been reported in patients who received ganciclovir and

PRIMAXIN. These drugs should not be used concomitantly with PRIMAXIN unless the potential benefits outweigh the risks.

Probenecid

Concomitant administration of PRIMAXIN and probenecid results in increases in the plasma level and half-life of imipenem. Therefore, it is not recommended that probenecid be given concomitantly with PRIMAXIN.

Valproic Acid Case reports in the literature have shown that co-administration of

carbapenems, including PRIMAXIN, to patients receiving valproic acid or divalproex sodium results in a reduction in valproic acid concentrations. The valproic acid concentrations may drop below the therapeutic range as a result of this interaction, therefore increasing the risk of breakthrough seizures. Although the mechanism of this interaction is unknown, data from in vitro and animal studies suggest that carbapenems may inhibit the hydrolysis of valproic acid's glucuronide metabolite (VPA-g) back to valproic acid, thus decreasing the serum concentrations of valproic acid.

The concomitant use of PRIMAXIN and valproic acid/divalproex sodium is generally not recommended. Antibacterials other than carbapenems should be considered to treat infections in patients whose seizures are well-controlled on valproic acid or divalproex sodium.

Pregnancy Risk Summary Available data from a small number of postmarketing cases with PRIMAXIN use in pregnancy are not sufficient to identify any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes. Developmental toxicity studies with imipenem and cilastatin sodium (alone or in combination) administered to mice, rats, rabbits, and monkeys at doses 0.4 to 2.9 times the recommended human dose (RHD), (based on body surface area), showed no drug-induced fetal malformations. Embryofetal development studies with imipenem/cilastatin administered to cynomolgus monkeys at doses similar to the RHD (based on body surface area) showed an increase in embryonic loss (see Data ). The background risk of major birth defects and miscarriage for the indicated populations is unknown.

All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The background risk of major birth defects is 2-4% and of miscarriage is 15-20% of clinically recognized pregnancies within the general population. Data Animal Data Reproductive toxicity studies with imipenem and cilastatin (alone or in combination) administered to mice, rats, and rabbits showed no evidence of effects on embryofetal (mice, rats and rabbits) or pre/postnatal (rats) development.

Imipenem was administered intravenously to rats (gestation days (GD) 7 to 17) and rabbits (GD 6 to 18) at doses up to 900 and 60 mg/kg/day, respectively, approximately 2.9 and 0.4 times the RHD (based on body surface area). Cilastatin was administered subcutaneously to rats (GD 6 to 17) and intravenously to rabbits (GD 6 to 18) at doses up to 1000 and 300 mg/kg/day, respectively, approximately 3.2 and 1.9 times the RHD (based on body surface area). Imipenem/cilastatin was administered intravenously to mice at doses up to 320 mg/kg/day (GD 6 to 15). In two separate studies, imipenem/cilastatin was administered to rats (GD 6 to 17 and GD 15 to day 21 postpartum) both intravenously at doses up to 80 mg/kg/day and subcutaneously at 320 mg/kg/day. The higher dose is approximately equal to the RHD (based on body surface area). Imipenem/cilastatin administered intravenously to pregnant cynomolgus monkeys during organogenesis at 100 mg/kg/day, approximately 0.6 times the RHD (based on body surface area), at an infusion rate mimicking human clinical use, was not associated with fetal malformations, but there was an increase in embryonic loss relative to controls. Imipenem/cilastatin administered to pregnant cynomolgus monkeys during organogenesis at 40 mg/kg/day by bolus intravenous injection caused significant maternal toxicity including death and embryofetal loss.

Pediatric Use Use of PRIMAXIN in pediatric patients is supported by evidence from adequate and well-controlled trials of PRIMAXIN in adults and clinical studies in pediatric patients . PRIMAXIN is not recommended in pediatric patients with CNS infections because of the risk of seizures. PRIMAXIN is not recommended in pediatric patients less than 30 kg with renal impairment, as no data are available.

is contraindicated in patients who have shown hypersensitivity to any component of this product. Known hypersensitivity to any component of PRIMAXIN

In the case of overdosage, discontinue PRIMAXIN, treat symptomatically, and institute supportive measures as required. PRIMAXIN is hemodialyzable.