SUMYCIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SUMYCIN (SUMYCIN).
Tetracycline antibiotic inhibiting bacterial protein synthesis by binding to the 30S ribosomal subunit, blocking aminoacyl-tRNA binding to the A site.
| Metabolism | Not extensively metabolized; primarily excreted unchanged in urine via glomerular filtration. |
| Excretion | Renal (60-80% unchanged via glomerular filtration), biliary/fecal (20-40%) |
| Half-life | 6-12 hours; prolonged in renal impairment (up to 24-48 hours in anuria) |
| Protein binding | 20-40%, primarily to albumin |
| Volume of Distribution | 1.5-2.0 L/kg; indicates extensive tissue distribution (e.g., lung, liver, bone) |
| Bioavailability | Oral: 30-50% (tetracycline base); higher for hydrochloride salt (60-80%) |
| Onset of Action | Oral: 1-2 hours; Intravenous: immediate |
| Duration of Action | 6-8 hours; longer with impaired renal function |
250-500 mg orally every 6 hours or 500 mg orally every 12 hours (maximum 2 g/day)
| Dosage form | TABLET |
| Renal impairment | CrCl 50-80 mL/min: 250 mg every 6 hours or 500 mg every 12 hours; CrCl 10-50 mL/min: 250 mg every 8-12 hours; CrCl <10 mL/min: 250 mg every 24 hours |
| Liver impairment | No dose adjustment required; however, use with caution in severe hepatic impairment due to potential hepatotoxicity. |
| Pediatric use | 25-50 mg/kg/day orally divided every 6 hours (maximum 2 g/day) |
| Geriatric use | No specific dose adjustment; monitor renal function and adjust dose based on creatinine clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SUMYCIN (SUMYCIN).
| Breastfeeding | Tetracycline is excreted into breast milk in low concentrations (M/P ratio approximately 0.5-0.8). However, due to the potential for serious adverse reactions (e.g., dental discoloration, bone growth inhibition) in nursing infants, a decision should be made to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. |
| Teratogenic Risk | Sumycin (tetracycline) is classified as FDA Pregnancy Category D. First trimester: Avoid due to possible teratogenic effects (limb anomalies, neural tube defects) based on animal data, but human data are limited. Second and third trimesters: Contraindicated due to risk of permanent tooth discoloration (yellow-gray-brown) and enamel hypoplasia in the fetus, and reversible inhibition of bone growth. Use after the 4th month of pregnancy is strongly discouraged. |
■ FDA Black Box Warning
Use during tooth development (last half of pregnancy, infancy, and childhood to 8 years) may cause permanent tooth discoloration and enamel hypoplasia; use during pregnancy may cause fetal harm; use in patients with renal impairment may lead to azotemia, hyperphosphatemia, and acidosis.
| Serious Effects |
Hypersensitivity to tetracyclines; pregnancy; breastfeeding; children under 8 years; severe hepatic impairment.
| Precautions | Photosensitivity reaction; superinfection with Clostridium difficile; hepatotoxicity; renal toxicity; use in pregnancy and children under 8 years; caution in renal impairment; may cause intracranial hypertension. |
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| Fetal Monitoring | Monitor maternal liver function, renal function, and blood counts. In pregnancy, serial ultrasound to assess fetal growth and development if exposure occurs during first trimester. For later exposure, monitor for signs of long bone growth inhibition and dental discoloration postnatally. |
| Fertility Effects | Tetracyclines have been associated with reversible impairment of fertility in animal studies, but human data on fertility effects are lacking. May affect spermatogenesis in males, but clinical significance is unknown. |