Cefotan

2nd Generation Cephalosporin and Cephamycin Antibiotics

Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.

Vial Reconstitution:
1 g vials: Reconstitute the 1 g vial with 10 mL of Sterile Water for Injection to give an approximate concentration of 95 mg/mL with an approximate withdrawable volume of 10.5 mL. Shake vials until powder is dissolved and let stand until solution is clear.[43953]
2 g vials: Reconstitute the 2 g vial with 10 to 20 mL of Sterile Water for Injection to give an approximate concentration of 95 to 182 mg/mL with an approximate withdrawable volume of 11 to 21 mL. Shake vials until powder is dissolved and let stand until solution is clear.[43953]
10 g bulk vials: Reconstitute the 10 g vial with 50 or 100 mL Sterile Water for Injection, 5% Dextrose Injection, or 0.9% Sodium Chloride Injection to give an approximate concentration of 180 or 95 mg/mL, respectively, and an approximate withdrawable volume of 55 or 105 mL. Shake vials until powder is dissolved and let stand until solution is clear. Withdrawal and transfer from the bulk vials should occur immediately, with a maximum time of 4 hours from the initial introduction of the diluent. Reconstituted solutions must be further diluted.[43944]
Storage: Reconstituted 1 or 2 g vials are stable for 24 hours at room temperature (25 degrees C or 77 degrees F), for 96 hours under refrigeration (5 degrees C or 41 degrees F), and for at least 1 week in the frozen state (-20 degrees C or 4 degrees F).[43953] Aliquots reconstituted from bulk vials are stable for 24 hours at room temperature, for 96 hours under refrigeration (5 degrees C or 41 degrees F), and for 1 week in the frozen state.[43944]
Frozen samples from vials should be thawed at room temperature before use. Do not refreeze.[43953]
 
Duplex System Reconstitution (Activation):
Unlatch side tab and unfold Duplex container.
To inspect powder, peel foil strip from drug chamber. Protect from light after removal of foil strip.
Refold and latch side tab until ready to activate.
If foil strip is removed, use within 7 days.
Do not use directly after storage by refrigeration. Allow product to equilibrate to room temperature before use.
To activate, unfold the Duplex container and point the set port in a downward direction. Starting at the hanger tab end, fold the Duplex container just below the diluent meniscus, trapping all of the air above the fold. Squeeze the folded diluent chamber until the seal between the diluent and powder opens, releasing the diluent into the powder chamber.
Agitate the liquid-powder mixture until the powder is completely dissolved.
Storage: Use within 12 hours of activation if stored at room temperature or within 5 days if stored under refrigeration. Do not freeze.[43945]
 
IV Push
Single-dose vials may be used for direct injection after reconstitution. Bulk vials and Duplex containers should not be used for direct injection.[43944] [43945] [43953]
Inject appropriate dose directly into a vein over 3 to 5 minutes.[43953]
 
Intermittent IV Infusion
Infuse over approximately 30 minutes.[43945]
Using an infusion system, cefotetan may be administered over a longer period through the tubing system by which the patient may be receiving other IV solutions. Butterfly or scalp vein-type needles are preferred for this type of infusion. However, it is recommended to temporarily discontinue the administration of other solutions at the same site.[43944] [43953] [43945]
Duplex delivery system: Do not use plastic containers in series connections to avoid air embolism. Point the set port downward, and starting at the hanger tab end, fold the Duplex container just below the solution meniscus, trapping all of the air above the fold. Squeeze the container until the seal between the reconstituted drug solution and set port opens, releasing liquid to the set port. Check for leaks by squeezing before attaching to IV set. Peel the foil cover from the set port and attach a sterile administration set.[43945]
Solutions of cefotetan must not be admixed with solutions containing aminoglycosides. If cefotetan and aminoglycosides are to be administered to the same patient, they must be administered separately and not as a mixed injection.[43944] [43945] [43953]

Reconstitution
Reconstitute vials with Sterile Water for Injection, 0.9% Sodium Chloride Injection, 0.5% Lidocaine HCl Injection, 1% Lidocaine HCl Injection, or Bacteriostatic Water for Injection.
1 g vials: Reconstitute with 2 mL of diluent to give an approximate concentration of 400 mg/mL with an approximate withdrawable volume of 2.5 mL.
2 g vials: Reconstitute with 3 mL of diluent to give an approximate concentration of 500 mg/mL with an approximate withdrawable volume of 4 mL.
Shake vials until powder is dissolved and let stand until solution is clear.
Storage: Reconstituted vials are stable for 24 hours at room temperature (25 degrees C or 77 degrees F), for 96 hours under refrigeration (5 degrees C or 41 degrees F), and for at least 1 week in the frozen state (-20 degrees C or 4 degrees F).[43953]
 
Intramuscular Injection
Inject deeply into a large muscle mass (i.e., upper outer quadrant of the gluteus maximus or lateral part of the thigh).[43953]

seizures / Delayed / 0-1.0
interstitial nephritis / Delayed / 0-1.0
pancytopenia / Delayed / Incidence not known
aplastic anemia / Delayed / Incidence not known
agranulocytosis / Delayed / Incidence not known
angioedema / Rapid / Incidence not known
Stevens-Johnson syndrome / Delayed / Incidence not known
erythema multiforme / Delayed / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
toxic epidermal necrolysis / Delayed / Incidence not known
C. difficile-associated diarrhea / Delayed / Incidence not known
azotemia / Delayed / Incidence not known
hemolytic anemia / Delayed / Incidence not known

elevated hepatic enzymes / Delayed / 1.2-1.2
eosinophilia / Delayed / 0.5-0.5
thrombocytosis / Delayed / 0.3-0.3
phlebitis / Rapid / 0.3-0.3
cholestasis / Delayed / Incidence not known
hyperbilirubinemia / Delayed / Incidence not known
leukopenia / Delayed / Incidence not known
thrombocytopenia / Delayed / Incidence not known
bleeding / Early / Incidence not known
neutropenia / Delayed / Incidence not known
colitis / Delayed / Incidence not known
vaginitis / Delayed / Incidence not known
pseudomembranous colitis / Delayed / Incidence not known
candidiasis / Delayed / Incidence not known
superinfection / Delayed / Incidence not known

diarrhea / Early / 1.3-1.3
rash / Early / 0.7-0.7
pruritus / Rapid / 0.2-0.2
nausea / Early / 0.2-0.2
injection site reaction / Rapid / Incidence not known
urticaria / Rapid / Incidence not known
vomiting / Early / Incidence not known
abdominal pain / Early / Incidence not known
fever / Early / Incidence not known

Cefotan

Rx

Parenteral second-generation cephalosporin
Used for abdominal and soft-tissue infections, respiratory tract infections, and UTIs
Longer half-life allows for twice-daily dosing compared to cefoxitin, which requires usual dosing of 4 times per day

1 to 2 g IV every 12 hours for mild to moderate infections, 2 g IV every 12 hours for severe infections, and 3 g IV every 12 hours for life-threatening infections.

1 to 2 g IM every 12 hours for mild to moderate infections.

1 g IV or IM every 12 hours or 2 g IV every 24 hours for mild/moderate infections, 2 g IV every 12 hours for severe infections, and 3 g IV every 12 hours for life-threatening infections. For infections caused by Klebsiella pneumoniae, 1 to 2 g IV or IM every 12 hours.

1 to 2 g IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 6 hours from the first preoperative dose. May continue 1 to 2 g IV every 12 hours for no more than 24 hours post-operatively if necessary. Guidelines recommend cefotetan for gastrointestinal procedures, such as colorectal surgery, biliary tract procedures, and appendectomy (nonperforated), as well as for hysterectomy.

40 mg/kg/dose (Max: 2 g/dose) IV as a single dose within 30 to 60 minutes prior to the surgical incision; consider intraoperative redosing 6 hours from the first preoperative dose. May continue 40 mg/kg/dose (Max: 2 g/dose) IV every 12 hours for no more than 24 hours post-operatively if necessary. Guidelines recommend cefotetan for gastrointestinal procedures, such as colorectal surgery, biliary tract procedures, and appendectomy (nonperforated).

1 to 2 g IV as a single dose as soon as the umbilical cord is clamped.

1 to 2 g IV or IM every 12 hours for mild to moderate infections, 2 g IV or IM every 12 hours for severe infections, and 3 g IV every 12 hours for life-threatening infections. Treat complicated infections with adequate source control for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.

60 to 100 mg/kg/day (Max: 6 g/day) IV or IM divided every 12 hours. Treat complicated infections with adequate source control for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.

500 mg IV or IM every 12 hours; 1 to 2 g IV or IM every 24 hours; 1 to 2 g IV or IM every 12 hours. For life-threatening infections, the recommended dose is 3 g IV every 12 hours.

1 to 2 g IV or IM every 12 hours.

30 to 50 mg/kg/dose (Max: 2 g /dose) IV or IM every 12 hours.

2 g IV every 12 hours in combination with doxycycline. Cefotetan should be continued for at least 24 to 48 hours after clinical improvement, and then stepdown to oral doxycycline and metronidazole for a total of 14 days of therapy.

2 g IV every 12 hours in combination with doxycycline. Cefotetan should be continued for at least 24 to 48 hours after clinical improvement, and then stepdown to oral doxycycline and metronidazole for a total of 14 days of therapy.

2 g IV every 12 hours during the intrapartum period as an alternative. Give 1 additional dose after cesarean delivery; an additional dose is generally not needed after vaginal delivery. Other risk factors such as bacteremia or persistent postpartum fever may require additional therapy.

2 g IV every 12 hours during the intrapartum period as an alternative. Give 1 additional dose after cesarean delivery; an additional dose is generally not needed after vaginal delivery. Other risk factors such as bacteremia or persistent postpartum fever may require additional therapy.

†Indicates off-label use

Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.

Adult patients
FDA-labeled renal adjustments :
CrCl more than 30 mL/minute: No dosage adjustment needed.
CrCl 10 to 30 mL/minute: Usual dose administered every 24 hours or one-half usual dose every 12 hours.
CrCl less than 10 mL/minute: Usual dose administered every 48 hours or one-quarter usual dose every 12 hours.
 
Alternative renal adjustments :
CrCl more than 50 mL/minute: No dosage adjustment needed.
CrCl 10 to 50 mL/minute: Usual dose administered every 24 hours.
CrCl less than 10 mL/minute: Usual dose administered every 48 hours.
 
Pediatric patients
The following dosage adjustments are based on a usual recommended dose in pediatric patients of 40 to 80 mg/kg/day divided every 12 hours :
CrCl 30 mL/minute/1.73 m2 or more: No dosage adjustment needed.
CrCl 10 to 29 mL/minute/1.73 m2: 20 to 40 mg/kg/dose IV or IM every 24 hours.
CrCl less than 10 mL/minute/1.73 m2: 20 to 40 mg/kg/dose IV or IM every 48 hours.
 
Intermittent Hemodialysis
Cefotetan is dialyzable; therefore, for patients undergoing intermittent hemodialysis, one-quarter of the usual recommended dose should be given every 24 hours on days between dialysis and one-half the usual recommended dose on the day of dialysis. Alternatively, 1 g IV or IM after dialysis is also recommended. In pediatric patients, 20 to 40 mg/kg/dose IV or IM every 48 hours on hemodialysis days after dialysis.
 
Peritoneal dialysis
In adult patients, 1 g IV or IM every 24 hours. In pediatric patients, 20 to 40 mg/kg/dose IV or IM every 48 hours.
 
Continuous renal replacement therapy (CRRT)
In adult patients, 1 to 2 g IV or IM every 24 hours. In pediatric patients, 20 to 40 mg/kg/dose IV or IM every 12 hours.

Acetaminophen; Aspirin, ASA; Caffeine: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Acetaminophen; Aspirin: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Acetaminophen; Aspirin; Diphenhydramine: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Amikacin: (Minor) Cefotetan's product label states that cephalosporins may potentiate the adverse renal effects of nephrotoxic agents, such as aminoglycosides. Carefully monitor renal function, especially during prolonged therapy or use of high aminoglycoside doses. The majority of reported cases involve the combination of aminoglycosides and cephalothin or cephaloridine, which are associated with dose-related nephrotoxicity as singular agents. Limited but conflicting data with other cephalosporins have been noted.
Aminoglycosides: (Minor) Cefotetan's product label states that cephalosporins may potentiate the adverse renal effects of nephrotoxic agents, such as aminoglycosides. Carefully monitor renal function, especially during prolonged therapy or use of high aminoglycoside doses. The majority of reported cases involve the combination of aminoglycosides and cephalothin or cephaloridine, which are associated with dose-related nephrotoxicity as singular agents. Limited but conflicting data with other cephalosporins have been noted.
Aminosalicylate sodium, Aminosalicylic acid: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Butalbital; Caffeine: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Caffeine: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Caffeine; Orphenadrine: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Carisoprodol: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Carisoprodol; Codeine: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Citric Acid; Sodium Bicarbonate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Dipyridamole: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Omeprazole: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Aspirin, ASA; Oxycodone: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Bismuth Subsalicylate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Bismuth Subsalicylate; Metronidazole; Tetracycline: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Butalbital; Aspirin; Caffeine; Codeine: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Choline Salicylate; Magnesium Salicylate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Diflunisal: (Minor) Certain cephalosporins with a methylthiotetrazole (MTT) side chain, such as cefotetan, can cause hypoprothrombinemia, which increases the potential for hemorrhage. Additionally, cefotetan can disturb the synthesis of vitamin K-dependent clotting factors in the liver. Cefotetan should be used cautiously with diflunisal due to the possibility of bleeding.
Ethanol: (Major) Cefotetan has been reported to cause disulfiram-like reactions when administered to patients who have ingested ethanol. It is recommended that patients receiving this combination be warned about the possible disulfiram-like reaction. Ethanol should be avoided during and for 2-3 days after discontinuing therapy with cefotetan.
Gentamicin: (Minor) Cefotetan's product label states that cephalosporins may potentiate the adverse renal effects of nephrotoxic agents, such as aminoglycosides. Carefully monitor renal function, especially during prolonged therapy or use of high aminoglycoside doses. The majority of reported cases involve the combination of aminoglycosides and cephalothin or cephaloridine, which are associated with dose-related nephrotoxicity as singular agents. Limited but conflicting data with other cephalosporins have been noted.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Loop diuretics: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Magnesium Salicylate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Methenamine; Sodium Salicylate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Oral Contraceptives: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Paromomycin: (Minor) Cefotetan's product label states that cephalosporins may potentiate the adverse renal effects of nephrotoxic agents, such as aminoglycosides. Carefully monitor renal function, especially during prolonged therapy or use of high aminoglycoside doses. The majority of reported cases involve the combination of aminoglycosides and cephalothin or cephaloridine, which are associated with dose-related nephrotoxicity as singular agents. Limited but conflicting data with other cephalosporins have been noted.
Plazomicin: (Minor) Cefotetan's product label states that cephalosporins may potentiate the adverse renal effects of nephrotoxic agents, such as aminoglycosides. Carefully monitor renal function, especially during prolonged therapy or use of high aminoglycoside doses. The majority of reported cases involve the combination of aminoglycosides and cephalothin or cephaloridine, which are associated with dose-related nephrotoxicity as singular agents. Limited but conflicting data with other cephalosporins have been noted.
Salicylates: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Salsalate: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Major) Prior or concomitant use of antibiotics with sodium picosulfate; magnesium oxide; anhydrous citric acid may reduce efficacy of the bowel preparation as conversion of sodium picosulfate to its active metabolite bis-(p-hydroxy-phenyl)-pyridyl-2-methane (BHPM) is mediated by colonic bacteria. If possible, avoid coadministration. Certain antibiotics (i.e., tetracyclines and quinolones) may chelate with the magnesium in sodium picosulfate; magnesium oxide; anhydrous citric acid solution. Therefore, these antibiotics should be taken at least 2 hours before and not less than 6 hours after the administration of sodium picosulfate; magnesium oxide; anhydrous citric acid solution.
Streptomycin: (Minor) Cefotetan's product label states that cephalosporins may potentiate the adverse renal effects of nephrotoxic agents, such as aminoglycosides. Carefully monitor renal function, especially during prolonged therapy or use of high aminoglycoside doses. The majority of reported cases involve the combination of aminoglycosides and cephalothin or cephaloridine, which are associated with dose-related nephrotoxicity as singular agents. Limited but conflicting data with other cephalosporins have been noted.
Tobramycin: (Minor) Cefotetan's product label states that cephalosporins may potentiate the adverse renal effects of nephrotoxic agents, such as aminoglycosides. Carefully monitor renal function, especially during prolonged therapy or use of high aminoglycoside doses. The majority of reported cases involve the combination of aminoglycosides and cephalothin or cephaloridine, which are associated with dose-related nephrotoxicity as singular agents. Limited but conflicting data with other cephalosporins have been noted.
Warfarin: (Moderate) The concomitant use of warfarin with many classes of antibiotics, including cephalosporins, may increase the INR thereby potentiating the risk for bleeding. Inhibition of vitamin K synthesis due to alterations in the intestinal flora may be a mechanism; however, concurrent infection is also a potential risk factor for elevated INR. Additionally, certain cephalosporins (cefotetan, cefoperazone, cefamandole) are associated with prolongation of the prothrombin time due to the methylthiotetrazole (MTT) side chain at the R2 position, which disturbs the synthesis of vitamin K-dependent clotting factors in the liver. Monitor patients for signs and symptoms of bleeding. Additionally, increased monitoring of the INR, especially during initiation and upon discontinuation of the antibiotic, may be necessary.

Cefotan/Cefotetan/Cefotetan Disodium Intramuscular Inj Pwd F/Sol: 1g, 2g
Cefotan/Cefotetan/Cefotetan Disodium Intravenous Inj Pwd F/Sol: 1g, 2g, 10g

6 g/day IV; 4 g/day IM.

6 g/day IV; 4 g/day IM.

Safety and efficacy have not been established; however, doses up to 100 mg/kg/day IV/IM are used off-label; do not exceed the FDA-approved adult Max of 6 g/day IV; 4 g/day IM.

Safety and efficacy have not been established; however, doses up to 100 mg/kg/day IV/IM are used off-label; do not exceed the FDA-approved adult Max of 6 g/day IV; 4 g/day IM.

Safety and efficacy have not been established; however, doses up to 100 mg/kg/day IV/IM are used off-label.

Safety and efficacy have not been established.

Cefotetan is a bactericidal cephamycin antibiotic that inhibits the third and final stage of bacterial cell wall synthesis by preferentially binding to specific penicillin-binding proteins (PBPs) that are located inside the bacterial cell wall. PBPs are responsible for several steps in the synthesis of the cell wall and are found in quantities of several hundred to several thousand molecules per bacterial cell. PBPs vary among different bacterial species. Like all beta-lactam antibiotics, cefotetan's ability to interfere with PBP-mediated cell wall synthesis ultimately leads to cell lysis. Lysis is mediated by bacterial cell wall autolytic enzymes (i.e., autolysins). The relationship between PBPs and autolysins is unclear, but it is possible that the beta-lactam antibiotic interferes with an autolysin inhibitor. Cefotetan has activity in the presence of beta-lactamases, both penicillinases and cephalosporinases, of some gram-negative and gram-positive bacteria.[28646] [43953] [44649] [51465]
 
Beta-lactams, including cefotetan, exhibit concentration-independent or time-dependent killing. In vitro and in vivo animal studies have demonstrated that the major pharmacodynamic parameter that determines efficacy for beta-lactams is the amount of time free (non-protein bound) drug concentrations exceed the minimum inhibitory concentration (MIC) of the organism (free T above the MIC).[34143] [34145] [35436] [35437] [35438] [35439] This microbiological killing pattern is due to the mechanism of action, which is acylation of PBPs. There is a maximum proportion of PBPs that can be acylated; therefore, once maximum acylation has occurred, killing rates cannot increase.[35439] Free beta-lactam concentrations do not have to remain above the MIC for the entire dosing interval. The percentage of time required for both bacteriostatic and maximal bactericidal activity is different for the various classes of beta-lactams. Cephalosporins require free drug concentrations to be above the MIC for 35% to 40% of the dosing interval for bacteriostatic activity and 60% to 70% of the dosing interval for bactericidal activity.[35436] [35437] [35438]
 
The susceptibility interpretive criteria for cefotetan are delineated by pathogen. The MICs are defined for H. influenzae and H. parainfluenzae as susceptible at 4 mcg/mL or less, intermediate at 8 mcg/mL, and resistant at 16 mcg/mL or more. The MICs are defined for Enterobacterales and anaerobes as susceptible at 4 mcg/mL or less, intermediate at 8 mcg/mL, and resistant at 16 mcg/mL or more by the FDA; however, the CLSI definitions are susceptible at 16 mcg/mL or less, intermediate at 32 mcg/mL, and resistant at 64 mcg/mL or more. The MICs are defined for N. gonorrhoeae as susceptible at 4 mcg/mL or less, intermediate at 8 mcg/mL, and resistant at 16 mcg/mL or more by the FDA; however, the CLSI definitions are susceptible at 2 mcg/mL or less, intermediate at 4 mcg/mL, and resistant at 8 mcg/mL or more. Oxacillin-susceptible staphylococci can be considered susceptible to cefotetan. The FDA MIC interpretive criteria are based on a dosing regimen of 2 g IV every 12 hours.[63320] [63321]
 
Resistance to cefotetan is primarily through hydrolysis by some beta-lactamases, alteration of PBPs, and decreased drug permeability.[43953]

Cefotetan is administered intramuscularly and intravenously; it is not well absorbed from the GI tract. Approximately 78% to 91% of the circulating drug is protein-bound. It is distributed into many body tissues and fluids including skin, muscle, fat, gallbladder, kidney, bladder, uterus, cervix, ovary, lung, bile as well as peritoneal, pleural, and synovial fluids. It does not reach therapeutic concentrations within the CSF. In adult single-dose trials, the volume of distribution ranged from 7.2 to 16.7 L (weight-based Vd not reported). Cefotetan is not metabolized to a significant degree; it is largely excreted unchanged into the urine via glomerular filtration and tubular secretion. In normal patients, 51% to 81% of a dose is excreted unchanged in the urine within a 24-hour period, which results in high and prolonged urinary concentrations. There is a linear correlation between systemic clearance and CrCl. The elimination half-life is 3 to 4.6 hours in adult patients with normal renal function, which allows for twice-daily dosing.
 
Affected cytochrome P450 isoenzymes and drug transporters: none

Peak concentrations (Cmax) are reached immediately after completion of an IV infusion or IV push injection in adults. Cmax has been shown to be higher with IV push administration compared with IV infusion. Cmax values of 55 to 216 mcg/mL are achieved after doses of 10 to 20 mg/kg in children; in adults who received a 2 g dose IV over 3 minutes, the mean plasma concentration 10 minutes after the dose was 223 mcg/mL.

Cefotetan is well absorbed after IM administration. Peak concentrations are reached 1.5 to 3 hours after IM administration. Peak concentrations have been shown to be approximately 25% to 50% lower with IM administration compared with IV administration. The use of lidocaine for IM administration does not affect the pharmacokinetic or pharmacodynamic properties.

Cefotetan crosses the placenta and is present in the amniotic fluid. Data over several decades with cephalosporin use, including cefotetan, during pregnancy have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. Cefotetan administered for prophylaxis at the time of labor and obstetric delivery has not been associated with any adverse reactions in the infant. Maternal gonorrhea may be associated with preterm birth, low neonatal birth weight, chorioamnionitis, intrauterine growth restriction, small for gestational age and premature rupture of membranes. Perinatal transmission of gonorrhea to the offspring can result in infant blindness, joint infections, and bloodstream infections. In animal reproduction studies, no adverse developmental effects were observed at cefotetan doses up to 2 to 3 times the maximum recommended human dose (MRHD) during organogenesis.[43945]

Cefotetan is present in human milk at low concentrations after intravenous administration. There is no information regarding the effects of cefotetan on milk production or the breast-fed infant. Consider the developmental and health benefits of breast-feeding along the with monther's clinical need for cefotetan and any potential adverse effects on the breast-fed child from cefotetan or the underlying maternal condition.[43945]