ACHROMYCIN V
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ACHROMYCIN V (ACHROMYCIN V).
Bacteriostatic; binds reversibly to 30S ribosomal subunit, inhibits protein synthesis by blocking aminoacyl-tRNA binding to mRNA-ribosome complex.
| Metabolism | Not extensively metabolized; primarily excreted unchanged in urine via glomerular filtration; small amount metabolized in liver. |
| Excretion | Renal (60% unchanged in urine via glomerular filtration), biliary/fecal (40% as active drug and metabolites, with a portion undergoing enterohepatic recirculation). |
| Half-life | Terminal elimination half-life is 6-12 hours in patients with normal renal function; prolonged in renal impairment (up to 48-72 hours in anuria). |
| Protein binding | 50-65% bound to serum albumin; primarily binds to alpha-1-acid glycoprotein. |
| Volume of Distribution | 1.5-2.0 L/kg (large volume indicates extensive tissue distribution, concentrating in bile, liver, kidneys, and bone; minimal CNS penetration despite lipophilicity). |
| Bioavailability | Oral: 60-80% (reduced by food, particularly dairy products, due to chelation with divalent cations). Intravenous: 100%. |
| Onset of Action | Oral: 1-2 hours (bacteriostatic effect begins after adequate serum levels achieved). Intravenous: immediate upon infusion. |
| Duration of Action | 12-24 hours (serum levels above MIC for susceptible organisms persist for 12-24 hours post-dose; clinical duration may exceed serum half-life due to tissue reservoirs). |
| Molecular Weight | 444.43 |
250-500 mg orally every 6 hours
| Dosage form | CAPSULE |
| Renal impairment | GFR 50-80 mL/min: no adjustment; GFR 10-50 mL/min: 250-500 mg every 12-24 hours; GFR <10 mL/min: 250-500 mg every 24 hours |
| Liver impairment | No dosage adjustment required; use with caution in severe hepatic impairment due to potential hepatotoxicity |
| Pediatric use | Children >8 years: 25-50 mg/kg/day orally divided every 6 hours |
| Geriatric use | Consider age-related renal impairment; adjust dose based on GFR; avoid if possible due to increased risk of photosensitivity and gastrointestinal effects |
| 1st trimester | Contraindicated due to risk of fetal harm; tetracyclines can cause transient skeletal growth retardation and permanent tooth discoloration. |
| 2nd trimester | Contraindicated; associated with fetal skeletal and dental abnormalities. |
| 3rd trimester | Contraindicated; risk of dental enamel hypoplasia and bone growth retardation. |
Clinical note
Comprehensive clinical and safety monograph for ACHROMYCIN V (ACHROMYCIN V).
| Placental transfer | Tetracyclines cross the placenta readily; concentrations in fetal serum and tissues are 50-75% of maternal levels. |
| Breastfeeding | Tetracyclines are excreted into breast milk in low amounts; however, due to potential for dental staining and bone growth suppression in nursing infants, use is generally avoided. Short-term use (e.g., <2 weeks) may be acceptable if benefits outweigh risks; monitor infant for rash or gastrointestinal disturbances. |
■ FDA Black Box Warning
Use during tooth development (last half of pregnancy, infancy, childhood to age 8 years) may cause permanent discoloration of teeth (yellow-gray-brown).
| Serious Effects |
Hypersensitivity to tetracyclinesPregnancyLactation (unless short-term and benefits outweigh risks)Children under 8 years (due to tooth discoloration and bone growth inhibition)Severe hepatic or renal impairment
| Precautions | Photosensitivity manifested by exaggerated sunburn reaction, Renal impairment may lead to drug accumulation and potential hepatotoxicity, Superinfection with resistant organisms including fungi, Bone growth retardation in premature infants, Pseudotumor cerebri (benign intracranial hypertension) in adults |
| Food/Dietary | Avoid dairy products (milk, cheese, yogurt) and calcium-fortified foods within 2-4 hours of dosing. Also avoid concurrent intake of iron-rich foods or supplements, zinc, magnesium, and antacids. High-fat meals may reduce absorption; take on an empty stomach. |
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| Lactation Rating | L2 (Safer, but caution advised) |
| Teratogenic Risk | Tetracyclines, including ACHROMYCIN V (tetracycline hydrochloride), are classified as FDA Pregnancy Category D. Use during the second and third trimesters may cause permanent tooth discoloration (yellow-gray-brown) and enamel hypoplasia in the fetus. Reversible inhibition of bone growth has been reported. First-trimester exposure is associated with a small risk of neural tube defects and other malformations in some studies. Avoid use during pregnancy unless for serious infections (e.g., anthrax, brucellosis) when alternative antibiotics are contraindicated. |
| Fetal Monitoring | Maternal: Monitor for gastrointestinal intolerance, photosensitivity, hepatotoxicity (especially in pregnant patients with renal impairment), and signs of superinfection. Fetal/neonatal: No specific monitoring is required for single, short-term use; however, prolonged use may warrant dental and bone development assessments in the infant after birth. |
| Fertility Effects | Tetracycline has no known direct effects on fertility in animal studies. In humans, no significant impact on male or female fertility has been reported. However, underlying infections may affect reproductive function; treat the infection appropriately. |
| Clinical Pearls | Tetracycline chelates with divalent and trivalent cations; avoid concurrent administration with dairy, antacids, iron, or calcium supplements. Photosensitivity risk: advise sun avoidance and use of sunscreen. Monitor renal function in elderly; adjust dose in severe renal impairment. Not for use in pregnancy or children under 8 years due to tooth discoloration and bone growth inhibition. Administer on an empty stomach (1 hour before or 2 hours after meals) for optimal absorption. |
| Patient Advice | Take this medication on an empty stomach, at least 1 hour before or 2 hours after meals. · Avoid dairy products, antacids, iron supplements, and calcium supplements within 2-4 hours of taking this drug. · Protect your skin from sun exposure; use sunscreen and wear protective clothing as this medicine can cause severe sunburn. · Do not take this drug if you are pregnant or breastfeeding; it can harm the baby's teeth and bones. · Complete the full course of treatment even if you feel better; do not skip doses. · Report any signs of allergic reaction, severe headache, blurred vision, or persistent diarrhea to your doctor immediately. · Store at room temperature away from moisture and light. |