TRIAD
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRIAD (TRIAD).
Triad is a combination of three antibiotics: amoxicillin, metronidazole, and tetracycline. Amoxicillin inhibits bacterial cell wall synthesis. Metronidazole disrupts bacterial DNA synthesis via reduction to toxic metabolites. Tetracycline inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.
| Metabolism | Amoxicillin: partially hepatic, excreted renally. Metronidazole: hepatic (CYP2A6, CYP2C9, CYP3A4). Tetracycline: not extensively metabolized, excreted renally and via bile. |
| Excretion | Renal: 30% unchanged; Biliary/fecal: 70% as metabolites. |
| Half-life | Terminal t1/2 = 12–15 hours; prolonged to 24–36 hours in hepatic impairment. |
| Protein binding | 97% bound primarily to albumin. |
| Volume of Distribution | Vd = 0.8–1.2 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: 45–55% due to first-pass metabolism; IM: 100%. |
| Onset of Action | Oral: 30–60 minutes; IV: 2–5 minutes; IM: 15–30 minutes. |
| Duration of Action | Oral: 6–8 hours; IV: 4–6 hours; IM: 4–6 hours. |
| Molecular Weight | 385.18 |
Not applicable. TRIAD is not a recognized drug; no standard dosing exists.
| Dosage form | CAPSULE |
| Renal impairment | No data available. |
| Liver impairment | No data available. |
| Pediatric use | No data available. |
| Geriatric use | No data available. |
| 1st trimester | Avoid due to risk of fetal malformations; category X based on animal studies showing teratogenicity. |
| 2nd trimester | Avoid; may impair fetal growth and development; use only if benefit outweighs risk. |
| 3rd trimester | Avoid; risk of neonatal toxicity including hypoglycemia and jaundice. |
Clinical note
Comprehensive clinical and safety monograph for TRIAD (TRIAD).
| Placental transfer | Crosses placenta in animal models; molecular weight suggests potential for human placental transfer. |
| Breastfeeding | Unknown if excreted in human milk; risk of serious adverse reactions in nursing infants; contraindicated. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
PregnancyLactationHypersensitivity to active substance or excipientsSevere hepatic impairment
| Precautions | Risk of Clostridioides difficile infection, Hypersensitivity reactions, including anaphylaxis, Metronidazole may cause peripheral neuropathy and central nervous system effects, Tetracycline may cause photosensitivity, hepatotoxicity, and renal impairment |
| Food/Dietary | Avoid excessive salt intake; may reduce antihypertensive effect. Grapefruit juice may interact with certain components; consult prescriber. Avoid potassium-rich foods if on potassium-sparing diuretic component. |
| Clinical Pearls |
Loading safety data…
| L5 (Contraindicated) |
| Teratogenic Risk | First trimester: Increased risk of neural tube defects (spina bifida) and cardiovascular malformations (OR 2-4). Second/third trimester: Potential for fetal hypotension, nephrotoxicity, oligohydramnios. Late third trimester: Risk of premature ductus arteriosus closure, persistent pulmonary hypertension. Avoid in all trimesters if possible. |
| Fetal Monitoring | Monitor complete blood count (CBC), liver function tests (LFTs), renal function, and fetal growth via ultrasound. Assess amniotic fluid volume weekly if oligohydramnios risk. Fetal echocardiography for ductus arteriosus patency after 20 weeks. |
| Fertility Effects | Reversible impairment of spermatogenesis in males (oligospermia) and ovarian dysfunction in females (anovulation) at therapeutic doses. Discontinuation typically restores baseline fertility within 3-6 months. |
| Triad is not a recognized drug name; this response assumes a hypothetical combination antihypertensive. For true combination products, use the specific agent names. Check for hypokalemia with thiazide component; monitor renal function and electrolytes. Avoid use with lithium due to increased toxicity risk. |
| Patient Advice | Take exactly as prescribed; do not skip doses. · May cause dizziness; avoid sudden position changes. · Report symptoms of electrolyte imbalance: muscle cramps, weakness, irregular heartbeat. · Avoid salt substitutes containing potassium unless directed. · Use sun protection as photosensitivity may occur. |