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Geopen: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Geopen - General Information

Broad-spectrum semisynthetic penicillin derivative used parenterally. It is susceptible to gastric juice and penicillinase and may damage platelet function. [PubChem]

 

Pharmacology of Geopen

Geopen is a semisynthetic penicillin. Though carbenicillin provides substantial in vitro activity against a variety of both gram-positive and gram-negative microorganisms, the most important aspect of its profile is in its antipseudomonal and antiproteal activity. Because of the high urine levels obtained following administration, carbenicillin has demonstrated clinical efficacy in urinary infections due to susceptible strains of: Escherichia coli, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Pseudomonas species, Providencia rettgeri, Enterobacter species, and Enterococci (S. faecalis).

 

Geopen for patients

Patients should be counseled that antibacterial drugs including Geocillin should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When Geocillin is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by Geocillin or other antibacterial drugs in the future.

 

Geopen Interactions

Geocillin (carbenicillin indanyl sodium) blood levels may be increased and prolonged by concurrent administration of probenecid.

 

Geopen Contraindications

Geocillin is ordinarily contraindicated in patients who have a known penicillin allergy.

 

Additional information about Geopen

Geopen Indication: For the treatment of acute and chronic infections of the upper and lower urinary tract and in asymptomatic bacteriuria due to susceptible strains of bacteria. Mechanism Of Action: Free carbenicillin is the predominant pharmacologically active fraction of the salt. Geopen exerts its antibacterial activity by interference with final cell wall synthesis of susceptible bacteria. Penicillins acylate the penicillin-sensitive transpeptidase C-terminal domain by opening the lactam ring. This inactivation of the enzyme prevents the formation of a cross-link of two linear peptidoglycan strands, inhibiting the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that carbenicillin interferes with an autolysin inhibitor. Drug Interactions: Methotrexate The penicillin increases the effect and toxicity of methotrexateAnisindione The IV penicillin increases the anticoagulant effectDemeclocycline Possible antagonism of actionDicumarol The IV penicillin increases the anticoagulant effectAcenocoumarol The IV penicillin increases the anticoagulant effectDoxycycline Possible antagonism of actionWarfarin The IV penicillin increases the anticoagulant effectEthinyl Estradiol This anti-infectious agent could decreases the effect of the oral contraceptiveMestranol This anti-infectious agent could decreases the effect of the oral contraceptiveMethacycline Possible antagonism of actionMinocycline Possible antagonism of actionOxytetracycline Possible antagonism of actionRolitetracycline Possible antagonism of actionTetracycline Possible antagonism of action Food Interactions: Take on an empty stomach. Generic Name: Carbenicillin Synonyms: Carboxybenzylpenicillin acid; Carboxybenzylpenicillin; Carbenicillinum [INN-Latin]; Carbenicilline [INN-French]; Carbenicillina [DCIT]; Carbenicilina [INN-Spanish]; alpha-Carboxybenzylpencillin Drug Category: Anti-Bacterial Agents Drug Type: Small Molecule; Approved Other Brand Names containing Carbenicillin: Geopen; Pyopen; Absorption: Rapidly absorbed from the small intestine following oral administration. Oral bioavailability is 30 to 40%. Toxicity (Overdose): Carbenicillin blood levels achievable are very low, and toxic reactions as a function of overdosage should not occur systematically. The oral LD50 in mice is 3,600 mg/kg, in rats 2,000 mg/kg, and in dogs is in excess of 500 mg/kg. The lethal human dose is not known. Symptoms of overdose include diarrhea, nausea, stomach upset, and vomiting. Protein Binding: 30 to 60% Biotransformation: Minimal. Half Life: 1 hour Dosage Forms of Geopen: Tablet, film coated Oral Chemical IUPAC Name: (2S,5R,6R)-6-[(3-hydroxy-3-oxo-2-phenylpropanoyl)amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid Chemical Formula: C17H18N2O6S Carbenicillin on Wikipedia: https://en.wikipedia.org/wiki/Carbenicillin Organisms Affected: Enteric bacteria and other eubacteria