ARESTIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ARESTIN (ARESTIN).
Minocycline is a semisynthetic tetracycline antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, preventing the addition of amino acids to the elongating peptide chain. This action is bacteriostatic. In periodontal disease, it also inhibits matrix metalloproteinases (MMPs), particularly collagenase, and suppresses inflammatory cytokine production, reducing tissue destruction.
| Metabolism | Minocycline is extensively metabolized in the liver via multiple pathways, with at least 6 metabolites identified. The major metabolic routes include hydroxylation at the 9-position (via CYP450 enzymes, possibly CYP3A4) and N-demethylation. It also undergoes glucuronidation. The drug has a long half-life (11–17 hours) and undergoes enterohepatic recirculation. |
| Excretion | Minocycline is primarily eliminated via hepatic metabolism and biliary/fecal excretion. Renal excretion accounts for approximately 10-20% of the dose, with the remainder excreted in feces via bile. Less than 10% is recovered unchanged in urine. |
| Half-life | The terminal elimination half-life of minocycline is 11-17 hours (mean ~16 hours). This long half-life allows for twice-daily dosing in systemic use, but for Arestin (subgingival), local sustained release provides prolonged local exposure. |
| Protein binding | Minocycline is approximately 70-75% bound to plasma proteins. |
| Volume of Distribution | Volume of distribution for minocycline is 1.0-1.3 L/kg, indicating extensive tissue penetration, consistent with its lipophilic nature and ability to concentrate in various tissues including gingival crevicular fluid. |
| Bioavailability | Subgingival administration: Direct local delivery results in negligible systemic absorption (bioavailability <1% relative to oral dose). Oral minocycline bioavailability is approximately 90-100%. |
| Onset of Action | Subgingival administration: Clinical improvement in periodontal parameters (reduction in probing depth) is typically observed within 2-4 weeks after application, as the drug is released over 10-14 days. |
| Duration of Action | The subgingival microsphere formulation releases minocycline for approximately 10-14 days, providing sustained local antibiotic concentrations. Clinical effect (reduction in pocket depth) may persist for several weeks after complete release, supporting a 3-month re-treatment interval. |
| Molecular Weight | 493.94 |
1 mg subgingival application per periodontal pocket, applied as a single dose by a dental professional.
| Dosage form | POWDER, EXTENDED RELEASE |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | Not recommended in pediatric patients below 18 years of age due to lack of safety and efficacy data. |
| Geriatric use | No specific dose adjustment; use with caution due to potential age-related comorbidities. |
| 1st trimester | ARESTIN (minocycline HCl microspheres) is classified as FDA Pregnancy Category D. Tetracyclines can cause fetal harm when administered to a pregnant woman. They cross the placenta and may cause permanent discoloration of teeth and retardation of skeletal development. Use during first trimester is contraindicated unless absolutely necessary and no alternative exists. |
| 2nd trimester | Same as t1: Category D. Tetracyclines are known to cause tooth discoloration and impaired bone growth in the fetus. Use during second trimester is contraindicated unless no safer alternative is available. |
| 3rd trimester | Same as t1: Category D. Tetracyclines can cause fetal tooth discoloration and bone growth retardation. Use during third trimester is contraindicated unless absolutely necessary. |
Clinical note
Comprehensive clinical and safety monograph for ARESTIN (ARESTIN).
| Placental transfer | Minocycline crosses the placenta. Studies in animals and humans show that tetracyclines are transferred across the placenta and can cause fetal harm, including tooth discoloration and bone growth retardation. The degree of transfer is sufficient to achieve fetal serum levels that are 25-100% of maternal levels. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to minocycline or any tetracyclinePregnancy (Category D)Children under 8 years of age (risk of permanent tooth discoloration and bone growth inhibition)
| Precautions | Photosensitivity: May cause exaggerated sunburn; avoid prolonged sun exposure., Superinfection: Use may result in overgrowth of nonsusceptible organisms, including fungi., Hepatotoxicity: Rare cases of liver injury; discontinue if symptoms occur., Renal impairment: Use with caution in renal dysfunction; may accumulate., Autoimmune syndromes: Cases of drug-induced lupus, serum sickness-like reactions, and vasculitis reported., Intracranial hypertension: Associated with minocycline; symptoms include headache and blurred vision., Tooth discoloration: May cause permanent discoloration of teeth in children under 8 years., Bone development: Use during pregnancy may affect fetal skeletal development. |
| Food/Dietary | No known food interactions. Patients should avoid hard, crunchy, or sticky foods for at least 7 days after application to prevent mechanical disruption of the microspheres. |
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| Breastfeeding | Minocycline is excreted into breast milk in low concentrations. However, tetracyclines are generally considered compatible with breastfeeding due to low absorption by the infant, but caution is advised because of potential for dental staining and bone growth inhibition. The American Academy of Pediatrics considers minocycline compatible with breastfeeding. However, alternative agents with better safety profiles are preferred. |
| Lactation Rating | L2 (Limited data - probably compatible) |
| Teratogenic Risk | ARESTIN (minocycline hydrochloride) is a tetracycline antibiotic. Class D: Positive evidence of human fetal risk. Use contraindicated in pregnancy. Risk is highest in second and third trimesters due to tetracycline deposition in fetal bones and teeth, causing permanent discoloration and enamel hypoplasia. Potential for reversible inhibition of bone growth. First trimester exposure may be associated with neural tube defects and cardiac malformations, though data are limited. |
| Fetal Monitoring | Monitor for maternal hepatotoxicity, renal function, and signs of hypersensitivity. In pregnant patients (if inadvertent exposure), perform fetal ultrasound to assess for skeletal anomalies and cardiac defects. Newborns exposed in utero should have dental evaluation after eruption and assessment for bone growth. |
| Fertility Effects | Animal studies have shown reduced fertility and impaired spermatogenesis at high doses. Human data are limited; potential for reversible effects on female fertility. No definitive evidence of permanent impact on fertility. |
| Clinical Pearls | ARESTIN (minocycline microspheres) is a locally administered antibiotic adjunct to scaling and root planing (SRP) for periodontitis. Do not use in patients with known hypersensitivity to tetracyclines. Avoid placement in areas with active abscesses. Apply only into periodontal pockets ≥5 mm. Do not pack deeply; overfill may cause tissue irritation. No systemic antibiotic effect; monitor for local adverse effects like pain or swelling. |
| Patient Advice | Do not brush, floss, or use interdental cleaners in the treated area for 7 days after application. · Avoid eating hard, crunchy, or sticky foods for 1 week to prevent dislodging the microspheres. · Some minor discomfort, redness, or swelling at the application site is normal and usually resolves within days. · Report severe pain, swelling, or signs of infection (e.g., pus, fever) to your dentist promptly. · Continue routine oral hygiene in untreated areas as directed by your dentist. |