TERRAMYCIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TERRAMYCIN (TERRAMYCIN).
Inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, preventing aminoacyl-tRNA from binding to the A site.
| Metabolism | Primarily excreted unchanged in urine and feces. Undergoes enterohepatic circulation. Not extensively metabolized; minor hepatic metabolism via glucuronidation. |
| Excretion | Renal (primarily glomerular filtration, 20-60% unchanged in urine), biliary/fecal (10-30% via bile into feces). |
| Half-life | Terminal elimination half-life: 8-10 hours in normal renal function; prolonged to 20-40 hours in severe renal impairment (creatinine clearance <10 mL/min). |
| Protein binding | 20-40% bound primarily to serum albumin. |
| Volume of Distribution | 1.3-1.7 L/kg; distributes extensively into tissues including bone, liver, and bile; does not penetrate cerebrospinal fluid significantly. |
| Bioavailability | Oral: 70-80% (fasting); reduced by food or divalent cations; Intramuscular: 80-100%. |
| Onset of Action | Oral: 1-2 hours; Intravenous: immediate; Intramuscular: 0.5-1 hour. |
| Duration of Action | Approximately 6-8 hours after oral dose; 12-24 hours after IV or IM administration; clinical effect correlates with serum levels >1-2 mcg/mL. |
| Action Class | Tetracyclines |
| Brand Substitutes | TM 500mg Capsule, Oticycline 500mg Capsule, Oxy 500mg Capsule, TM 250mg Capsule, T M SF Capsule, Oticycline 250mg Capsule, T M 250mg Capsule |
250-500 mg orally every 6 hours or 1-2 g intravenously every 12 hours. Maximum oral dose: 2 g/day.
| Dosage form | SYRUP |
| Renal impairment | For GFR 10-50 mL/min: administer every 12-24 hours; for GFR <10 mL/min: administer every 24 hours and consider therapeutic drug monitoring. |
| Liver impairment | No specific Child-Pugh based dose adjustment is established; use with caution in severe hepatic impairment (Child-Pugh C) and monitor liver function. |
| Pediatric use | Children >8 years: 25-50 mg/kg/day orally divided every 6 hours; maximum 2 g/day. Intravenously: 10-20 mg/kg/day divided every 12 hours; maximum 1 g/day. |
| Geriatric use | Start at lower end of dosing range (250 mg orally every 6 hours or 500 mg IV every 12 hours) due to possible renal impairment; adjust based on renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TERRAMYCIN (TERRAMYCIN).
| Breastfeeding | Oxytetracycline is excreted in human milk. The milk-to-plasma ratio is approximately 0.6-0.8. Theoretical risks include dental staining and bone growth suppression in the nursing infant. Because of the potential for serious adverse reactions, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. |
| Teratogenic Risk | Terramycin (oxytetracycline) is a tetracycline antibiotic. Tetracyclines can cause fetal harm when administered to a pregnant woman. Use during the second and third trimesters may cause permanent discoloration of teeth (yellow-gray-brown) and enamel hypoplasia. Additionally, they can inhibit fetal skeletal growth. Use during the first trimester is associated with a slightly increased risk of neural tube defects, though data are limited. Therefore, use is contraindicated in pregnancy unless no alternative exists. |
■ FDA Black Box Warning
Use during tooth development (last half of pregnancy, infancy, and children up to 8 years) may cause permanent discoloration of teeth (yellow-gray-brown) and enamel hypoplasia. Not recommended for use during pregnancy or in children under 8 years except for anthrax, plague, or other serious infections.
| Serious Effects |
["Hypersensitivity to tetracyclines","Pregnancy (especially second and third trimesters)","Children under 8 years (except for specific indications)","Severe hepatic impairment","Systemic lupus erythematosus (may exacerbate)","Concurrent use with oral retinoids (increased risk of pseudotumor cerebri)"]
| Precautions | ["Photosensitivity","Superinfection","CNS effects (pseudotumor cerebri)","Hepatotoxicity","Renal toxicity (in patients with renal impairment)","Antianabolic effects (elevated BUN)","Pancreatitis","Esophageal ulceration","Tetracycline-antacid interaction","Use in pregnancy category D","Use in nursing mothers"] |
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| Fetal Monitoring | Monitor maternal renal and hepatic function due to potential toxicity. In pregnancy, consider fetal ultrasound to monitor for skeletal abnormalities if used during second/third trimester. Also monitor for signs of maternal superinfection or gastrointestinal disturbances. |
| Fertility Effects | Tetracyclines have been shown to cause reduced fertility in animal studies. In humans, no definitive evidence of impaired fertility has been reported, but due to potential ovarian and testicular toxicity, caution is advised in patients attempting conception. |