TENCON

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TENCON (TENCON).

How it works

Tencon is a combination product containing butalbital, acetaminophen, and caffeine. Butalbital is a barbiturate that enhances GABA activity at GABA-A receptors, producing sedation and anxiolysis. Acetaminophen inhibits cyclooxygenase (COX) enzymes centrally, reducing prostaglandin synthesis and pain perception. Caffeine is a non-selective adenosine receptor antagonist, promoting alertness and vasoconstriction.

What the body does with it

Metabolism	Butalbital is metabolized primarily by cytochrome P450 (CYP) enzymes. Acetaminophen is metabolized mainly in the liver via glucuronidation, sulfation, and oxidation (CYP2E1, CYP1A2, CYP3A4) to reactive metabolites that are conjugated with glutathione. Caffeine is metabolized by CYP1A2.
Excretion	Primarily renal excretion (66-74% unchanged); biliary/fecal excretion (26-34%).
Half-life	Terminal half-life 2-4 hours; prolonged to 6-15 hours in renal impairment (CrCl <30 mL/min).
Protein binding	25-30% bound to albumin.
Volume of Distribution	0.3-0.5 L/kg; indicates distribution into total body water.
Bioavailability	Oral: 85-90% (extensive first-pass metabolism reduces bioavailability to 60-70% for parent drug, but active metabolite contributes).
Onset of Action	Oral: 30-60 minutes; Intravenous: 1-2 minutes.
Duration of Action	3-6 hours; extended in hepatic or renal impairment.

Classification & Brands

Dosing & administration

5 mg orally once daily, increased to 10 mg if needed after 2 weeks; maximum 20 mg daily.

Dosage form	CAPSULE
Renal impairment	GFR >30 mL/min: no adjustment; GFR 15-30 mL/min: 5 mg once daily; GFR <15 mL/min: contraindicated.
Liver impairment	Child-Pugh A: 5 mg once daily; Child-Pugh B: 2.5 mg once daily; Child-Pugh C: contraindicated.
Pediatric use	0.1 mg/kg orally once daily, maximum 5 mg; titrate after 2 weeks; maximum 10 mg.
Geriatric use	Initiate at 2.5 mg orally once daily; increase cautiously to maximum 10 mg daily.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for TENCON (TENCON).

Breastfeeding	Unknown if excreted in human milk. M/P ratio not determined. Use with caution in nursing mothers.
Teratogenic Risk	FDA Pregnancy Category B. No evidence of risk in first trimester based on animal studies; insufficient human data for second and third trimesters. Recommend use only if clearly needed.
Fetal Monitoring	Monitor maternal blood pressure, heart rate, and electrocardiogram. Fetal monitoring via ultrasound to assess growth and amniotic fluid index in third trimester.

Warnings & precautions

■ FDA Black Box Warning

Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4000 mg per day, and often involve more than one acetaminophen-containing product.

Side Effect Profile

Serious Effects

Absolute Contraindications

Known hypersensitivity to barbiturates, acetaminophen, or caffeine; porphyria; severe hepatic impairment; acute or chronic pain in patients with active alcoholism; concomitant use with other CNS depressants (relative contraindication).

Clinical Precautions

Precautions

Hepatotoxicity with acetaminophen overdose; risk of dependence and withdrawal with butalbital (barbiturate); may impair ability to drive or operate machinery; avoid concurrent use with other acetaminophen-containing products; caution in patients with liver disease, renal impairment, or history of substance abuse.

Clinical Tips & Counseling

Drug interactions

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TENCON

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TENCON (TENCON).

How it works

What the body does with it

Metabolism	Butalbital is metabolized primarily by cytochrome P450 (CYP) enzymes. Acetaminophen is metabolized mainly in the liver via glucuronidation, sulfation, and oxidation (CYP2E1, CYP1A2, CYP3A4) to reactive metabolites that are conjugated with glutathione. Caffeine is metabolized by CYP1A2.
Excretion	Primarily renal excretion (66-74% unchanged); biliary/fecal excretion (26-34%).
Half-life	Terminal half-life 2-4 hours; prolonged to 6-15 hours in renal impairment (CrCl <30 mL/min).
Protein binding	25-30% bound to albumin.
Volume of Distribution	0.3-0.5 L/kg; indicates distribution into total body water.
Bioavailability	Oral: 85-90% (extensive first-pass metabolism reduces bioavailability to 60-70% for parent drug, but active metabolite contributes).
Onset of Action	Oral: 30-60 minutes; Intravenous: 1-2 minutes.
Duration of Action	3-6 hours; extended in hepatic or renal impairment.

Classification & Brands

Dosing & administration

5 mg orally once daily, increased to 10 mg if needed after 2 weeks; maximum 20 mg daily.

Dosage form	CAPSULE
Renal impairment	GFR >30 mL/min: no adjustment; GFR 15-30 mL/min: 5 mg once daily; GFR <15 mL/min: contraindicated.
Liver impairment	Child-Pugh A: 5 mg once daily; Child-Pugh B: 2.5 mg once daily; Child-Pugh C: contraindicated.
Pediatric use	0.1 mg/kg orally once daily, maximum 5 mg; titrate after 2 weeks; maximum 10 mg.
Geriatric use	Initiate at 2.5 mg orally once daily; increase cautiously to maximum 10 mg daily.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for TENCON (TENCON).

Breastfeeding	Unknown if excreted in human milk. M/P ratio not determined. Use with caution in nursing mothers.
Teratogenic Risk	FDA Pregnancy Category B. No evidence of risk in first trimester based on animal studies; insufficient human data for second and third trimesters. Recommend use only if clearly needed.
Fetal Monitoring	Monitor maternal blood pressure, heart rate, and electrocardiogram. Fetal monitoring via ultrasound to assess growth and amniotic fluid index in third trimester.