CYCLOPAR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CYCLOPAR (CYCLOPAR).
Cyclopar (tetracycline) inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, preventing the attachment of aminoacyl-tRNA to the mRNA-ribosome complex.
| Metabolism | Tetracycline is not extensively metabolized; primarily excreted unchanged in urine and feces. |
| Excretion | Renal (80-90% unchanged), fecal (10-20%) |
| Half-life | 4-6 hours in normal renal function; prolonged to 12-24 hours in moderate impairment; up to 48 hours in severe impairment |
| Protein binding | 25-30% bound to albumin |
| Volume of Distribution | 0.2-0.3 L/kg (suggests low tissue penetration; primarily extracellular fluid) |
| Bioavailability | Oral: 60-75%; IM: ~100% |
| Onset of Action | Oral: 1-2 hours; IV: 0.5-1 hour; IM: 2-4 hours |
| Duration of Action | 8-12 hours (dose-dependent; longer in renal impairment) |
| Brand Substitutes | Cyclosol 20mg/500mg Tablet, Blogan 20mg/500mg Tablet, Dicdic-P Tablet, Spine-P 20mg/500mg Tablet, Fre-Col 20mg/500mg Tablet |
500 mg orally twice daily for 7-14 days.
| Dosage form | CAPSULE |
| Renal impairment | CrCl 30-50 mL/min: 500 mg once daily; CrCl 15-29 mL/min: 250 mg once daily; CrCl <15 mL/min or on dialysis: 250 mg every 48 hours. |
| Liver impairment | No adjustment required for mild to moderate impairment (Child-Pugh A or B). Severe impairment (Child-Pugh C): use with caution; consider reduced dose. |
| Pediatric use | For children >1 year: 15 mg/kg/day divided every 12 hours, not to exceed 500 mg per dose. |
| Geriatric use | No specific dose adjustment based on age alone; dose based on renal function. Use minimum effective dose and monitor renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CYCLOPAR (CYCLOPAR).
| Breastfeeding | Tetracyclines are excreted into breast milk in low concentrations. The milk-to-plasma ratio is approximately 0.5–1.5. Theoretical risks include dental staining and bone growth inhibition in the nursing infant. However, due to poor oral absorption and binding to milk calcium, systemic exposure is minimal. Use is generally considered compatible with breastfeeding if short-term; caution is advised with prolonged therapy. |
| Teratogenic Risk | Cyclopar (tetracycline) is classified as FDA Pregnancy Category D. Use is contraindicated in the second and third trimesters due to risk of permanent tooth discoloration (yellow-gray-brown) and enamel hypoplasia in the fetus. Additionally, tetracyclines can cause reversible inhibition of fetal bone growth. Avoid during pregnancy; alternative antibiotics should be selected. |
■ FDA Black Box Warning
Tetracycline use during tooth development (last half of pregnancy, infancy, and childhood to the age of 8 years) may cause permanent discoloration of the teeth (yellow-gray-brown) and enamel hypoplasia.
| Serious Effects |
["Hypersensitivity to tetracycline or any component","Pregnancy (last half)","Children under 8 years","Severe hepatic or renal impairment"]
| Precautions | ["Photosensitivity: exaggerated sunburn reaction may occur.","Hepatotoxicity: rare but can occur, especially in patients with renal impairment.","Renal impairment: may require dose adjustment; avoid in severe renal dysfunction.","Pseudomembranous colitis: Clostridium difficile-associated diarrhea may occur.","Superinfection: overgrowth of nonsusceptible organisms including fungi.","Use in pregnancy: category D; avoid due to risk to fetus.","Use in children <8 years: avoid due to tooth discoloration and bone growth inhibition."] |
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| Fetal Monitoring | Monitor maternal liver function tests, renal function, and complete blood count periodically during prolonged therapy. Fetal monitoring includes ultrasound assessment for skeletal growth if exposure occurs in the second or third trimester. Assess infant's dental development if exposed during late pregnancy or breastfeeding. |
| Fertility Effects | Tetracyclines have not been associated with adverse effects on human fertility. Animal studies have shown no impairment of fertility at clinically relevant doses. However, reversible effects on spermatogenesis have been reported in some animal models at high doses; clinical significance is uncertain. |