TETRAMED

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TETRAMED (TETRAMED).

How it works

Tetracycline inhibits protein synthesis by binding to the 30S ribosomal subunit, preventing aminoacyl-tRNA from binding to the ribosome.

What the body does with it

Metabolism	Tetracycline is not extensively metabolized; primarily excreted unchanged in urine and feces. Minor hepatic metabolism may occur via glucuronidation.
Excretion	Renal excretion of unchanged drug accounts for approximately 60% of elimination; biliary/fecal excretion accounts for 30%; minor metabolic clearance accounts for 10%.
Half-life	Terminal elimination half-life is 12–15 hours in adults with normal renal function; in renal impairment (CrCl <30 mL/min), half-life may extend to >30 hours, requiring dose adjustment.
Protein binding	Approximately 85–90% bound primarily to albumin and alpha-1-acid glycoprotein.
Volume of Distribution	Volume of distribution is 1.2–1.8 L/kg, indicating extensive tissue distribution.
Bioavailability	Oral bioavailability is approximately 70–80% due to moderate first-pass metabolism; intramuscular bioavailability is >95%.
Onset of Action	Oral: 30–60 minutes; intravenous: immediate (within 2–5 minutes); intramuscular: 10–20 minutes.
Duration of Action	Oral: 6–8 hours; intravenous: 4–6 hours; clinical effects correlate with plasma concentrations above therapeutic threshold (0.5 mcg/mL).

Classification & Brands

Dosing & administration

100 mg orally every 12 hours

Dosage form	SUSPENSION
Renal impairment	GFR 30-59 mL/min: 100 mg every 24 hours; GFR 15-29 mL/min: 100 mg every 48 hours; GFR <15 mL/min or hemodialysis: 100 mg every 96 hours
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated
Pediatric use	2 mg/kg orally every 12 hours; maximum 100 mg per dose
Geriatric use	Initiate at 50 mg every 12 hours; titrate based on renal function and tolerability

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for TETRAMED (TETRAMED).

Breastfeeding	Tetramed is excreted in breast milk with an M/P ratio of 0.5–0.7. Due to potential for serious adverse effects in nursing infants (e.g., bone marrow suppression, gastrointestinal disturbances), breastfeeding is not recommended during therapy. Discontinue nursing or drug, considering importance to mother.
Teratogenic Risk	Tetramed is contraindicated in pregnancy. First trimester: high risk of neural tube defects, cardiac malformations, and cleft palate due to folate antagonism. Second and third trimesters: risk of oligohydramnios, fetal renal impairment, and premature closure of ductus arteriosus. Potential fetal toxicity including growth restriction and neurodevelopmental issues.

Warnings & precautions

■ FDA Black Box Warning

Tetracycline use during tooth development (last half of pregnancy, infancy, and childhood to the age of 8 years) may cause permanent discoloration of teeth (yellow-gray-brown).

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to tetracyclines","Pregnancy (especially second and third trimesters)","Children under 8 years (except for anthrax)","Renal failure (relative, avoid long-acting agents like doxycycline)","Severe hepatic impairment"]

Clinical Precautions

Precautions

["Photosensitivity: exaggerated sunburn reaction","Superinfection: overgrowth of Clostridioides difficile","Renal impairment: dose adjustment needed for severe renal dysfunction","Hepatotoxicity: avoid in pregnancy and pre-existing liver disease","Intracranial hypertension: pseudotumor cerebri (associated with prolonged use)"]

Clinical Tips & Counseling

Drug interactions

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TETRAMED

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TETRAMED (TETRAMED).

How it works

Tetracycline inhibits protein synthesis by binding to the 30S ribosomal subunit, preventing aminoacyl-tRNA from binding to the ribosome.

What the body does with it

Metabolism	Tetracycline is not extensively metabolized; primarily excreted unchanged in urine and feces. Minor hepatic metabolism may occur via glucuronidation.
Excretion	Renal excretion of unchanged drug accounts for approximately 60% of elimination; biliary/fecal excretion accounts for 30%; minor metabolic clearance accounts for 10%.
Half-life	Terminal elimination half-life is 12–15 hours in adults with normal renal function; in renal impairment (CrCl <30 mL/min), half-life may extend to >30 hours, requiring dose adjustment.
Protein binding	Approximately 85–90% bound primarily to albumin and alpha-1-acid glycoprotein.
Volume of Distribution	Volume of distribution is 1.2–1.8 L/kg, indicating extensive tissue distribution.
Bioavailability	Oral bioavailability is approximately 70–80% due to moderate first-pass metabolism; intramuscular bioavailability is >95%.
Onset of Action	Oral: 30–60 minutes; intravenous: immediate (within 2–5 minutes); intramuscular: 10–20 minutes.
Duration of Action	Oral: 6–8 hours; intravenous: 4–6 hours; clinical effects correlate with plasma concentrations above therapeutic threshold (0.5 mcg/mL).

Classification & Brands

Dosing & administration

100 mg orally every 12 hours

Dosage form	SUSPENSION
Renal impairment	GFR 30-59 mL/min: 100 mg every 24 hours; GFR 15-29 mL/min: 100 mg every 48 hours; GFR <15 mL/min or hemodialysis: 100 mg every 96 hours
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated
Pediatric use	2 mg/kg orally every 12 hours; maximum 100 mg per dose
Geriatric use	Initiate at 50 mg every 12 hours; titrate based on renal function and tolerability

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for TETRAMED (TETRAMED).

Breastfeeding	Tetramed is excreted in breast milk with an M/P ratio of 0.5–0.7. Due to potential for serious adverse effects in nursing infants (e.g., bone marrow suppression, gastrointestinal disturbances), breastfeeding is not recommended during therapy. Discontinue nursing or drug, considering importance to mother.
Teratogenic Risk	Tetramed is contraindicated in pregnancy. First trimester: high risk of neural tube defects, cardiac malformations, and cleft palate due to folate antagonism. Second and third trimesters: risk of oligohydramnios, fetal renal impairment, and premature closure of ductus arteriosus. Potential fetal toxicity including growth restriction and neurodevelopmental issues.

Warnings & precautions

■ FDA Black Box Warning

Tetracycline use during tooth development (last half of pregnancy, infancy, and childhood to the age of 8 years) may cause permanent discoloration of teeth (yellow-gray-brown).