CINOXACIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CINOXACIN (CINOXACIN).
Inhibits bacterial DNA gyrase (topoisomerase II), blocking DNA replication and transcription.
| Metabolism | Hepatic metabolism via glucuronidation; also undergoes renal tubular secretion. |
| Excretion | Primarily renal excretion as unchanged drug (approximately 60-70%) and as glucuronide conjugates (approximately 20-30%). Biliary/fecal excretion accounts for less than 5%. |
| Half-life | Terminal elimination half-life is approximately 1.5 hours in healthy adults. Prolonged in renal impairment (up to 20-30 hours in anuria). |
| Protein binding | Approximately 60-70% bound to serum albumin and other plasma proteins. |
| Volume of Distribution | Apparent volume of distribution is 0.3-0.5 L/kg, consistent with distribution primarily into extracellular fluid. Low tissue penetration except in kidneys. |
| Bioavailability | Oral: Approximately 40-50% due to incomplete absorption and first-pass metabolism; however, urinary concentrations exceed MICs for susceptible pathogens. |
| Onset of Action | Oral: Clinical effect (urinary antibacterial activity) begins within 1-2 hours after oral administration. |
| Duration of Action | Urinary bactericidal concentrations persist for 8-12 hours after a single oral dose. Twice-daily dosing maintains therapeutic levels. |
1 g orally twice daily for 7-14 days.
| Dosage form | CAPSULE |
| Renal impairment | CrCl >50 mL/min: 1 g q12h; CrCl 30-50 mL/min: 500 mg q12h; CrCl <30 mL/min: 250 mg q12h. |
| Liver impairment | No specific adjustment required for hepatic impairment. |
| Pediatric use | Not recommended for use in pediatric patients. |
| Geriatric use | Use with caution; consider renal function and potential increased risk of adverse effects; start at lower end of dosing range. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CINOXACIN (CINOXACIN).
| Breastfeeding | Cinoxacin is excreted in human milk. The milk-to-plasma ratio is approximately 0.5. Due to potential serious adverse reactions in nursing infants, including arthropathy and CNS effects, breastfeeding is not recommended during therapy. |
| Teratogenic Risk | Cinoxacin is contraindicated in pregnancy. Animal studies have shown embryotoxicity and teratogenicity at high doses. Human data are limited but suggest potential fetal harm. First trimester exposure may be associated with congenital anomalies; second and third trimester exposure may cause fetal nephrotoxicity and ototoxicity. |
■ FDA Black Box Warning
Not applicable; no FDA black box warning.
| Serious Effects |
["Hypersensitivity to cinoxacin or other quinolones","Children under 18 years","Pregnancy (risk of arthropathy in immature animals)","Lactation"]
| Precautions | ["May cause tendonitis or tendon rupture (risk increased with corticosteroids, age >60, renal impairment)","May exacerbate myasthenia gravis","Peripheral neuropathy risk","Central nervous system effects including dizziness, confusion, and seizures","Photosensitivity reactions","Prolongation of QT interval (avoid with other QT-prolonging drugs)"] |
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| Fetal Monitoring | Monitor maternal renal function and CBC. Assess fetal growth and amniotic fluid index via ultrasound. If used inadvertently, monitor for fetal nephrotoxicity and ototoxicity. |
| Fertility Effects | In animal studies, cinoxacin has been associated with impaired fertility in males (reduced spermatogenesis) and females (extended estrous cycle and reduced conception rates). Human data are lacking; however, caution is advised in patients attempting conception. |