Zeptrigen

Ceftazidime.

Pharmacologic Classification: Antibacterial.
Pharmacology: Ceftazidime is a semi-synthetic, third-generation cephalosporin which exerts its bactericidal activity by interfering with the bacterial cell wall synthesis. It binds to specific penicillin-binding proteins responsible for the synthesis of peptidoglycan, a heteropolymeric structure that gives the cell wall its mechanical stability. The final stage of peptidoglycan synthesis involves completion of the cross-linking of the terminal glycine residue of the pentaglycine bridge to the fourth residue of the pentapeptide. The transpeptidase enzyme that catalyzes this step is inhibited by cephalosporins. As a result the bacterial cell wall is weakened, the cell swells and then ruptures.
Pharmacokinetics: Bioavailability: Ceftazidime is not absorbed from the gastrointestinal (GI) tract and must be administered parenterally.
After intramuscular (IM) administration of 500 mg and 1 g doses of ceftazidime in healthy adults, mean peak serum concentrations (C_max) were 17 and 29-39 mcg/mL, respectively, about 1 hour after the dose. Serum concentrations remained above 4 mcg/mL for 6 and 8 hours after IM administration of 500 mg and 1 g doses, respectively.
After intravenous (IV) administration of 500 mg and 1 g doses of ceftazidime over 3-5 minutes in healthy men, average serum concentrations at 0.25, 0.5, 1, 2, 4, 6, and 8 hours after dosing were 34.1, 24.5, 17.1, 11.2, 5.6, 2.1-2.4, and 0.9-1.3 mcg/mL, respectively, after the 500 mg dose and 59.9-83.3, 45.3-60.9, 32.1-40.9, 22.9-23.2, 9.7, 4.4-5.3, and 1.9-3.2 mcg/mL, respectively, after the 1 g dose.
After IV infusion of 500 mg and 1 g doses of ceftazidime over 20 to 30 minutes in healthy men, C_max of 42 and 69 mcg/mL, respectively, were achieved. Infusion of a single 2 g dose over 20 to 30 minutes in healthy adults resulted in C_max of 159-185.5 mcg/mL and average serum concentrations of 87.9, 65.2-70.6, 38.7, 16.7-16.9, and 7.7 mcg/mL at 0.5, 1, 2, 4, and 6 hours, respectively, after completion of the infusion.
Ceftazidime is widely distributed into body tissues and fluids including the gallbladder, bone, bile, skeletal muscle, prostatic tissue, endometrium, myometrium, heart, skin, adipose tissue, aqueous humor, and sputum, and pleural, peritoneal, synovial, ascitic, lymphatic, and blister fluids. It is generally distributed into bile, but biliary concentrations of the drug after IM or IV administration may be lower than concurrent serum concentrations.
Ceftazidime generally diffuses into cerebrospinal fluid (CSF) after IV administration, although CSF concentrations of the drug are higher in patients with inflamed meninges than in those with uniflamed meninges.
Ceftazidime crosses the placenta and is distributed into amniotic fluid. The drug is also distributed into milk. In lactating women with endometritis who received 2 g of ceftazidime IV every 8 hours, mean concentrations of the drug in milk obtained during days 2-4 of treatment were 3.8 mcg/mL immediately prior to a dose and 5.2 and 4.5 mcg/mL at 1 and 3 hours, respectively, after a dose.
About 5-24% of ceftazidime is bound to serum proteins. The degree of protein binding is independent of drug concentration.
Plasma ceftazidime concentrations decline in a biphasic manner. The distribution half-life (t_1/2) and elimination half-life (t_1/2) in adults with normal renal and hepatic function are 0.1-0.6 and 1.4-2 hours, respectively.
Ceftazidime is not metabolized and is excreted unchanged mainly by the kidneys, almost exclusively by glomerular filtration. After IM or IV administration of a single 500 mg or 1 g dose of ceftazidime in adults with normal renal function, 80-90% of the dose is excreted unchanged in urine within 24 hours; about 50% of the dose is excreted within 2 hours after the dose.
The mean serum clearance of ceftazidime in healthy adults is 98-122 mL/min.
The serum half-life of ceftazidime is longer in neonates than in older children and adults, but does not appear to be related to gestational age or birth weight.
Serum concentrations of ceftazidime are higher and serum half-life is prolonged in patients with renal impairment. The t_1/2 of ceftazidime in patients with creatinine clearances (CL_CR) of 39-73 mL/min, 13-27 mL/min, <10 mL/min were 3-4.6, 9.4-10.3, and 11.9-35 hours, respectively.
The serum half-life of ceftazidime is only slightly prolonged in patients with hepatic impairment and generally, drug accumulation does not occur in these patients unless renal function is also impaired.
Ceftazidime is removed by hemodialysis and peritoneal dialysis.

For the treatment of the following infections caused by susceptible microorganisms: Respiratory tract infections, including ear, nose and throat infections, pneumonia, lung infections in cystic fibrosis.
Skin and skin-structure infections.
Urinary tract infections (UTI), both complicated and uncomplicated.
Bone and joint infections.
Gynecologic infections, including endometritis, pelvic cellulitis, and other infections of the female genital tract.
Intra-abdominal infections, including peritonitis and polymicrobial infections.
Central Nervous System infections, including meningitis.
Bacterial Septicemia.
Dialysis: Infections associated with hemo- and peritoneal dialysis and with continuous ambulatory peritoneal dialysis (CAPD).
Other severe infections such as: Infections in immunocompromised patients.
Infections in patients in intensive care, e.g., infected burns.

For IV administration or by deep IM injection into a large muscle mass such as the upper outer quadrant of the gluteus maximus or lateral part of the thigh. Intra-arterial administration should be avoided since arteriospasm and distal necrosis can occur.
The dosage and route should be determined by the susceptibility of the causative organism, the severity of infection, and the condition and renal function of the patient.
Usual Adult Dosage: 1 g IV or IM every 8 to 12 hours.
Maximum Dose: 6 g/day.
Recommended Dosing Schedule for Specific Infection in Adults: See Table 1.

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Elderly: In view of the reduced clearance of ceftazidime in acutely ill elderly patients, the daily dosage should not normally exceed 3 g, especially in those >80 years old.
Patients with Renal Impairment: An initial loading dose of 1 g ceftazidime may be given in adults with suspected renal insufficiency (CL_CR ≤50 mL/min). Maintenance dosage is based on the patient's CL_CR as shown as follows: Recommended Maintenance Doses in Adults with Renal Impairment: See Table 2.

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When only serum creatinine is available, the following formula may be used to estimate CL_CR. The serum creatinine should represent a steady state of renal function: See equation.

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In patients with severe infections, especially in neutropenics, who would normally receive 6 g of ceftazidime daily were it not for renal insufficiency, the unit dose given in the table previously may be increased by 50% or the dosing frequency may be increased appropriately. In such patients it is recommended that ceftazidime serum levels should be monitored and trough levels should not exceed 40 mg/L. Further dosing should be determined by therapeutic monitoring, severity of infection, and susceptibility of the causative organism.
In patients undergoing hemodialysis, a loading dose of 1 g is recommended, followed by 1 g after each hemodialysis period.
Ceftazidime can also be used in patients undergoing intraperitoneal dialysis and continuous ambulatory peritoneal dialysis. In such patients, a loading dose of 1 g of ceftazidime may be given, followed by 500 mg every 24 hours.
Patients with Hepatic Impairment: No dosage adjustment is necessary.
Usual Pediatric Dosage: Neonates (0-4 weeks old): 30 mg/kg body weight IV every 12 hours.
Infants and children (1 month to 12 years old): 30-50 mg/kg body weight IV every 8 hours.
Maximum dose: 6 g/day.
The higher dose (i.e., 50 mg/kg body weight every 8 hours) should be reserved for immunocompromised pediatric patients or pediatric patients with cystic fibrosis or meningitis.
In pediatric patients, the CL_CR should be adjusted for body surface area or lean body mass, and the dosing frequency reduced in cases of renal insufficiency as for adults.
Duration of Treatment: The duration of treatment depends on the type and severity of infection and should be determined by the clinical and bacteriologic responses of the patient.
For most infections, treatment generally should be continued for at least 48 hours after the patient becomes asymptomatic or evidence of bacterial eradication has been obtained, but in complicated infections longer therapy may be required.
Antibiotic treatment in patient with meningitis caused by Gram-negative bacilli generally should be continued for at least 3 weeks. In neonates with meningitis, it is recommended that antibiotic treatment be continued for 2 weeks beyond the first sterile CSF culture or at least 3 weeks, whichever is longer.
Or, as prescribed by a physician.

Careful inquiry should be made concerning previous hypersensitivity to cephalosporins, penicillins or other drugs before initiating therapy with ceftazidime. If ceftazidime is to be given to penicillin-sensitive patients, caution should be exercised since cross-hypersensitivity among beta-lactam antibiotics has been clearly documented and may occur in up to 10% of patients with a history of penicillin allergy. If an allergic reaction to ceftazidime occurs, discontinue treatment with the drug.
Serious acute hypersensitivity reactions may require treatment with epinephrine and other emergency measures including oxygen, IV fluids, IV antihistamines, corticosteroids, pressor amines, and airway management as clinically indicated.
Clostridium difficile-associated diarrhea (CDAD) and colitis have been reported with the use of nearly all antibacterial agents, including ceftazidime, and may range in severity from mild to life threatening. It is important to consider this diagnosis in patients who present with diarrhea following administration of antibacterial agents.
Ceftazidime should be used with caution in patients with a history of lower GI disease, particularly colitis.
Ceftazidime is eliminated via the kidneys; therefore, dosage should be reduced according to the degree of renal impairment. Neurological sequelae have occasionally been reported when the dose has not been reduced appropriately (see Adverse Reactions).
Cephalosporins at high dosage should be given with caution to patients receiving nephrotoxic medicines or potent diuretics, as these combinations are suspected of adversely affecting renal function.
Cephalosporins may be associated with a fall in prothrombin activity. Patients who are at risk are those with renal or hepatic impairment or poor nutritional state, as well as patients receiving a protracted course of antimicrobial therapy, and patients previously stabilized on anticoagulant therapy. Prothrombin time should be monitored in patients at risk and exogenous Vitamin K administered as indicated.
As with other antibacterial drugs, long term or repeated use may result in overgrowth of non-susceptible organisms, including fungi.
Inducible type I beta-lactamase resistance has been noted with some organisms (e.g., Enterobacter spp., Pseudomonas spp. and Serratia spp.) may develop resistance during ceftazidime therapy. When ceftazidime is used to treat infections caused by these Gram-negative bacteria, periodic susceptibility testing should be performed when clinically appropriate. If patients fail to respond to monotherapy, an aminoglycoside or similar agent should be considered.
Prescribing ceftazidime in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of development of drug-resistant bacteria.

Ceftazidime is generally well-tolerated. The incidence of adverse reactions associated with ceftazidime use was low in clinical trials. The most common were local reactions after IV injection and allergic and GI reactions. No disulfiram-like reactions were reported.
The following adverse effects (AEs) were considered to be either related to ceftazidime therapy or were of uncertain etiology: Local Effects: Phlebitis or thrombophlebitis with IV administration, pain and/or inflammation at injection site after IM injection (mild to moderate for about 2-5 minutes and subsides within 10-20 minutes); distal necrosis can occur after inadvertent intra-arterial administration of ceftazidime.
Dermatologic/Hypersensitivity Reactions: Pruritus, rash (maculopapular or erythematous), urticaria, photosensitivity, fever, toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, angioedema, anaphylaxis (bronchospasm and/or hypotension); allergic reactions, which, in rare instances, were severe (e.g., cardiopulmonary arrest).
GI: Diarrhea, nausea, vomiting, abdominal pain, pseudomembranous colitis, metallic taste.
Nervous System: Headache, dizziness, paresthesia; elevated levels of ceftazidime in patients with renal impairment can lead to seizures, convulsions, asterixis, tremor, myoclonia, epilepsy, encephalitis/encephalopathy, neuromuscular excitability, hallucinations and coma.
Hematologic: Transient eosinophilia; reversible thrombocytosis; transient leukopenia, neutropenia, and thrombocytopenia; rare cases of hemolytic anemia, agranulocytosis, and lymphocytosis; positive Coombs' test without hemolysis.
Hepatobiliary: Transient increases in serum concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, lactate dehydrogenase (LDH), and/or γ-glutamyltransferase (γ-glutamyl transpeptidase, GGT, GGTP); hyperbilirubinemia; hepatitis and/or jaundice.
Renal Effects: Transient increases in blood urea, blood urea nitrogen (BUN) and/or serum creatinine concentrations; transient mild to moderate decrease in glomerular filtration; interstitial nephritis; renal failure although a causal relationship to the drug has not been established.
Other Adverse Effects: Less frequent AEs include candidiasis (oral thrush) and vaginitis; superinfections with organisms resistant to ceftazidime.
In addition to the AEs listed previously which have been observed in patients treated with ceftazidime, the following AEs have been reported for cephalosporin-class antibiotics: Hypersensitivity reactions including chills, joint pain or inflammation, arthralgia, edema, facial edema, erythema, shock, vasodilatation, and exfoliative dermatitis; leukocytosis, granulocytosis, monocytosis, lymphocytopenia, basophilia, decreased hemoglobin and/or hematocrit; aplastic anemia, pancytopenia, epistaxis or hemorrhage, hypoprothrombinemia; colitis, toxic nephropathy, hepatic dysfunction including cholestasis; prolonged prothrombin time, false-positive test for urinary glucose; increased or decreased serum glucose concentration; decreased serum albumin and/or total protein; vaginal candidiasis, menstrual irregularities; dizziness, malaise, fatigue, nightmares, vertigo, hyperactivity, nervousness or anxiety, agitation, sleep disorder/insomnia, somnolence, weakness, hot flushes, alteration in color perception, confusion, and hypertonia; chest pain, pleural effusion, pulmonary infiltrate, dyspnea or respiratory distress, cough, rhinitis.

Directions for Use, Compatibility and Stability: See Table 3.

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Reconstituted solutions are stable for 6 hours if stored at 30°C or for 72 hours at 2°C to 8°C.
Ceftazidime is compatible with any one of the following IV infusion fluids: 0.9% Sodium Chloride; 5% Dextrose; 10% Dextrose; 5% Dextrose and 0.45% Sodium Chloride; 5% Dextrose and 0.9% Sodium Chloride; Lactated Ringer's Solution; 1/6 M Sodium Lactate Solution; Ringer's Solution.
Incompatibilities: Ceftazidime is less stable in Sodium Bicarbonate injection than other IV fluids. It is not recommended as a diluent.
Ceftazidime and aminoglycosides should not be mixed in the same giving set or syringe.
Precipitation has been reported when vancomycin was added to ceftazidime in solution. It is recommended that giving sets and IV lines are flushed between administration of these two agents.
Prior to administration, parenteral drug products should be inspected visually for particulate matter and discoloration whenever solution and container permit.
Shake the reconstituted solution before use.
Observe strict aseptic technique when drawing up the contents of the vial. If contaminated, it has the potential to become a source of infection to patients.

Cephalosporins

J01DD02 - ceftazidime ; Belongs to the class of third-generation cephalosporins. Used in the systemic treatment of infections.

Rx

Powd for inj (vial) 500 mg x 1's. 1 g x 1's.