Drug Interaction:
Interacting drugs- summary
Impipenim- cilastatin +
Imipenem cilastatin + Ganciclovir
generalized seizures have occurred in patients receiving concomittant
imipenem-cilastatin IV. Do not use concomittantly unless potential
benefits outweigh the risks
Probenecid + Imipenem- Cilastatin
probenecid and concurrent imipenem- cilastatin results in only minimal
increase in imipenem plasma levels and half life , therfore it is not
recommended that probenecid to be given concurrently
Aztreonam
(eg. cefoxitin, imipenem ) induce high levels of Beta- lactamase
in vitro in some gram-negative aerobes such as Enterobacter and
Psuedomonas species resulting in antagonism to many Beta lactum
antibiotics including aztreonam. Beta-lactanase-inducing antibiotics
should not be used concomittantly with aztreonam
Indication:
Treatment of serious infections caused by suseptible strains - Lower resipratory tract infections Urinary tractvinfections Iintra-abdominal infections Gynaecologic infections Bacterial septicemia Bone and joint infectons
Adverse Reaction:
Lab test abnormalities
Hepatic- increased AST, ALT, alkaline phosphatase,bilirubin and LDH
Hemic- increased eosinophils, monocytes, lymphocytes,basophils, decreased neutrophils (including agranulocytosis) hemoglobin, hematocrit, increase WBCs and platelets, positive Coombs test, abnormal prothrombin time.
Electrolytes- decreased serum sodium, increased potassium and chloride Renal- increased BUN and creatinine
Urinalysis- presence of protein, RBCs, WBCs, casts,bilirubin, or urinogen in the urine
Local- phebitis/thrombophlebitis, pain at injection site, erythema at the injection site, vein induction, infused vein infection
GI- nausea, diarrhea, vomiting, pseudomembranous colitis, hemorrhagic colitis, hepatitis, gastroenteritis, abdominal pain, glossitis, tongue papiar hypertrophy, heartburn, pharyngeal pain, increased salivation.
CNS- fever, seizures, dizziness, somnolence, encephalopathy, tremor, confusion, myocolnus, parethesia, vertigo,headache, psychic disturbances
Respiratory- chest discomfort, dyspnea, hyperventilation
Dermatologic- rash, pruritus,urticaria, erythema mutiforme, toxic epidermal necrolysis, facial edema, flushing, cyanosis,skin texture changes, cadidiasis, pruritus vulvae
Miscellaneous- transcient hearing loss in patients with impaired hearing, tinnitus, polyarthralgia, taste perversion, asthenia/weakness, thoracic spine pain.
IM- Lab test abnormalities
Hemic- decreased hemoglobin, and hemotocrit, eosinophilia, increased/decreased WBCs, and platelets, decreased erythrocytes, increased prothrombin time Hepatic- increased AST. ALT, alkaline phosphatase and bilirubin
Renal- increased BUN and creatinine Urinalysis- presence of RBCs, WBCs, casts and bacteria in the urine
Local- pain at injection site
Systemic- nausea, diarrhea, vomiting, rash.thrombocytopenia, leukopenia, oliguria/anuria, polyuria, acute renal failure, hyperhidrosis
Contra-Indications:
Hypersenstivity to any component in the product IM- hypersenstivity to local anesthetics of the amide type and in patients with severe shock or heart block due to the use of lidocaine HCl diluent
Special precautions
Monitoring- while imipenem has the characterstic low toxicity of the betactum group of antibiotics periodicaly assess organ system function during prolonged therapy.
CNS -adverse experiences eg myoclonic activity, confusional states, have occured with IV formulatin, especially when the recommended dosages were exceeded. Closely adhere to the recommended dosage schedule especially in patients with known factors that predispose to convulsive activity.
Cross-allergenicity- individuals with a history of penicillin sensitivity may experience cross-sensitivity to imipenam-cilastatin. Use caution while administering to patients with a history of penicillin allergy.
Superinfection:
Use of antibiotics especially over a prolonged or repeated therapy may result in bacterial or fungal overgrowth of susecptible organisms. such overgrowth may lead to secondary infection. Take appropiate measures if this occurs.
Warnings
Pseudonomembranous colitis- has been reported when nearly all antibiotics. Consider this diagnosis in patients developing diarrhea while on antibiotics.Severity ranges from mild to life-threatening.
Mild cases will respond to drug disconuation. More severe cases may requie sigmoidoscopy appropriate bacterilogical studies, fliud , electrolye and protein supplementation.
Hypersensitivity- serious and occassionaly fatal hypersensitivity reactions occured in patients receiving therapy with betactums. They are more apt tro occur in patients with a history of sensitivity to multiple allergens. If a reaction occurs,discontinue the drug.
Pregnancy- Use only when the potential benefits outweigh potential hazards to the fetus.
Lactation- Excercise caution while administering to a nursing woman
Children- safey and efficacy for use in children < 12 years of age have not been established.
Dosages/ Overdosage Etc:
Indication-
Treatment of serious infections caused by suseptible strains - Lower resipratory tract infections Urinary tractvinfections Iintra-abdominal infections Gynaecologic infections Bacterial septicemia Bone and joint infectons
Dosage
IV- Give each 250 or 50mg dose by IV infusion over 20 to 30 min. Infuse each 1g dose over 40 to 60 min. In patients who develop nausea, slow the infusion rate. IM Total daily dosages > 1500mg /day are not recommended.
Children- Suggested dosage in children < 40kg is 60mg/kg/day. In children > 40kg use adult dosage. Premature infants < 36 weeks gestaional age may receive 20mg/kg/day every 12 hours. Use with caution in infants < 3 months of age.
Overdosage- Symptoms In case of overdosage discontinue the drug
Treatment
1. Treat symptomatically and institute supportive measures as required
2. Imipen-cilastatin is hemodialyzable, usefulness of this procedure is questonable.
Missed dose
1. If you miss a dose of this medicine, take it as soon as possible.
2. However, if it is almost time for next dose, skip the missed dose and go back to your regular dosing schedule.
3. Do not double doses.
Pharmacology/ Pharmacokinetics:
Pharmacology
This product is a formulation of imipenem, a thienamycin antibiotic and cilastatin sodium, the inhibitor of the renal dipeptidase, dehydropeptidase, which is responsible for the extensive metabolism of imipenem when it is administered alone. Cilastatin by inhibiting this dipeptidase prevents the metabolism of imipenem, thereby increasing urinary recovery and decreasing possible renal toxicity. The bacterial activity of imipenem results from the inhibition of cell wall synthesis, related to binding to penicillin binding proteins (PBP) 2 and 1B.
Pharmacokinetics
IV- infusion over 20 minutes results in peak plasma levels of imipenem antimicrobial activity that range from 14 to 24mcg/ml fo a 250mg dose, 58mcg/ml for the 500mg dose and from 41 to 83mcg/ml for 1g dose.. Plasma half-lfe of each component is app 1 hour. Urine imipenem concentratin > 10mcg/ml cam be maintained for upto 8 hours for 1g dose. IM- following IM administration of 500 to 750mg doses, peak plasma levels of imipenem antimicrobial activity occur within 2 hours and average 10 and 12mcg/ml respy. For cilastatin, peak plasma levels average 24 and 33mcg/ml ,respy and occur within 1 hour.
Pregnancy and lactation:
Pregnancy
Use only when the potential benefits outweigh potential hazards to the fetus.
Lactation
Excercise caution while administering to a nursing woman
Children- Safey and efficacy for use in children < 12 years of age have not been established.