Geocillin, Geopen Oral 
Classifications: antibiotic; antipseudomonal penicillin;
Therapeutic: antibiotic
; penicillin
Prototype: Piperacillin
Pregnancy Category: B


382 mg tablets


Broad-spectrum, semisynthetic penicillin that rapidly hydrolyzes to carbenicillin in body.

Therapeutic Effect

Like carbenicillin disodium, it is bactericidal and penicillinase sensitive and has similar antimicrobial activity but achieves lower blood concentrations than parent compound.


Mainly in the treatment of prostatitis and acute and chronic infections of upper and lower urinary tract.


Hypersensitivity to penicillins; coagulation disorders. Safe use in children not established.

Cautious Use

History of or suspected atopy or allergies; history of allergy to cephalosporins or carbapenem; colitis; diabetes mellitus; lactation; impaired renal and hepatic function; patients on sodium restriction; pregnancy (category B).

Route & Dosage

Urinary Tract Infections
Adult: PO 382–764 mg q6h for 10 d, continue for 2–4 wk for prostatitis


  • Give with a full glass (240 mL) of water on an empty stomach (either 1 h before or 2 h after meals) to attain maximum therapeutic drug levels in urine. Consult physician.
  • Protect tablets from moisture.

Adverse Effects (≥1%)

Body as a Whole: Hypersensitivity (rash, fever, urticaria, eosinophilia, pruritus, anaphylaxis), superinfections, especially of vagina. GI: Nausea, vomiting, heartburn; diarrhea, abdominal cramps, flatulence, unpleasant aftertaste, dry mouth. Hematologic: Neutropenia, leukopenia, thrombocytopenia, hemolytic anemia, increased AST.


Absorption: Incompletely from GI tract. Peak: 0.5–1 h. Distribution: Very low systemic concentrations; crosses placenta; distributed into breast milk. Elimination: 80–99% unchanged in urine within 24 h. Half-Life: 67 min.

Nursing Implications

Assessment & Drug Effects

  • Lab tests: Perform culture and sensitivity tests prior to and at regular intervals throughout therapy. Therapy may be initiated pending test results. Evaluate renal, hepatic, and hematopoietic systems at regular intervals during prolonged therapy. Patients with creatinine clearance of less than 10 mL/min (normal: 105–130 mL/min) will not attain therapeutic urine levels.
  • Inquire carefully concerning patient's previous exposure and sensitivity to penicillin and cephalosporins and other allergic reactions of any kind before treatment is initiated.
  • Note that drug-induced nausea, unpleasant aftertaste and smell, dry mouth, and furry tongue may be so objectionable as to necessitate drug withdrawal. Report to physician if symptoms persist.
  • Monitor I&O rates and pattern: Check with physician regarding optimum daily fluid intake. Report any change in quality or quantity of urine or in I&O ratio.
  • Observe patient for signs of electrolyte imbalance. Each 1 g of drug contains approximately 1 mEq of sodium.

Patient & Family Education

  • Take this medication with a full glass of water on an empty stomach.
  • Take medication around the clock, do not miss any doses, and continue taking medication until it is all gone unless otherwise directed by physician.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2023 Last Updated On: 01/29/2023 (0)
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