Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
AXOTAL vs TENCON
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Axotal contains butalbital, a barbiturate that enhances GABA-A receptor activity, and acetaminophen, an analgesic and antipyretic whose mechanism is not fully understood but may involve COX inhibition and activation of descending serotonergic pathways.
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.
Tension headache
Tension headache,Migraine headache (off-label)
Each tablet: butalbital 50 mg, acetaminophen 300-500 mg, caffeine 40 mg. 1-2 tablets orally every 4 hours as needed, not exceeding 6 tablets per day.
5 mg orally once daily, increased to 10 mg if needed after 2 weeks; maximum 20 mg daily.
Terminal elimination half-life is 2-4 hours in patients with normal renal function; prolonged to 8-12 hours in severe renal impairment (Cr Cl <30 m L/min).
Terminal half-life 2-4 hours; prolonged to 6-15 hours in renal impairment (Cr Cl <30 m L/min).
Butalbital is metabolized primarily by CYP2C19; acetaminophen is metabolized mainly via glucuronidation by UGT1A1 and UGT1A6, sulfation by SULT1A1, and minor oxidation by CYP2E1.
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.
Renal excretion of unchanged drug (60-70%) and glucuronide conjugates (10-20%); biliary excretion (5-10%); fecal elimination (<10%).
Primarily renal excretion (66-74% unchanged); biliary/fecal excretion (26-34%).
98-99% bound primarily to albumin; minor binding to alpha-1-acid glycoprotein.
25-30% bound to albumin.
0.15-0.25 L/kg, indicating distribution mainly in extracellular fluid and limited tissue penetration.
0.3-0.5 L/kg; indicates distribution into total body water.
Oral: 85-95%; intramuscular: 90-100%; intravenous: 100%.
Oral: 85-90% (extensive first-pass metabolism reduces bioavailability to 60-70% for parent drug, but active metabolite contributes).
No specific guidelines; contraindicated in severe renal impairment (Cr Cl <30 m L/min). Use with caution in mild-moderate impairment due to acetaminophen and butalbital accumulation.
GFR >30 m L/min: no adjustment; GFR 15-30 m L/min: 5 mg once daily; GFR <15 m L/min: contraindicated.
Contraindicated in Child-Pugh Class C (severe hepatic impairment). In Child-Pugh A or B, reduce dose or extend interval; maximum acetaminophen 2000 mg/day, avoid butalbital if possible.
Child-Pugh A: 5 mg once daily; Child-Pugh B: 2.5 mg once daily; Child-Pugh C: contraindicated.
Not recommended for children under 12 years. For ages 12-18: same as adult dose (1-2 tablets) but limit to 4 tablets per day and monitor for sedation.
0.1 mg/kg orally once daily, maximum 5 mg; titrate after 2 weeks; maximum 10 mg.
Start at lower dose (1 tablet every 6 hours) due to increased sensitivity to butalbital (c NS depression, falls) and acetaminophen hepatotoxicity risk; limit to 4 tablets per day, avoid in frail elderly.
Initiate at 2.5 mg orally once daily; increase cautiously to maximum 10 mg daily.
Acetaminophen has been associated with cases of acute liver failure, sometimes resulting in liver transplant and death. Hepatotoxicity is usually associated with doses exceeding 4000 mg per day and often involves more than one acetaminophen-containing product.
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.
Hepatotoxicity with acetaminophen overdose; risk of rhabdomyolysis, angioedema, Stevens-Johnson syndrome; butalbital dependence and withdrawal; CNS depression; impairment of mental or physical abilities; avoid concurrent alcohol use.
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.
Hypersensitivity to barbiturates or acetaminophen; porphyria; severe hepatic impairment; respiratory depression; history of substance abuse.
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).
Avoid alcohol intake; concurrent use increases risk of acetaminophen hepatotoxicity. Grapefruit juice may increase caffeine levels; limit consumption. High-fat meals may delay absorption of butalbital. Maintain adequate hydration; caffeine has mild diuretic effect.
Avoid alcohol consumption due to increased risk of acetaminophen hepatotoxicity and additive central nervous system depression. Limit caffeine-containing foods and beverages (coffee, tea, cola, chocolate) to avoid excessive stimulant effects and potential caffeine toxicity.
Pregnancy Category D. First trimester: Risk of cardiovascular malformations (e.g., Ebstein anomaly), neural tube defects, and oral clefts increased with lithium exposure. Second and third trimesters: Increased risk of fetal/neonatal toxicity including cardiac arrhythmias, hypoglycemia, polyhydramnios, preterm birth, and neonatal goiter. Avoid if possible; weigh risks vs. benefits.
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.
Lithium is excreted into human milk (M/P ratio 0.3-0.8). Breastfeeding is not recommended due to risk of neonatal toxicity (hypotonia, hypothermia, cyanosis, ECG changes). Monitor infant serum levels if breastfeeding is continued.
Unknown if excreted in human milk. M/P ratio not determined. Use with caution in nursing mothers.
Dose adjustments are often necessary due to increased glomerular filtration rate and expanded plasma volume. Monitor serum levels closely (every 2-4 weeks in second and third trimesters). Dose may need to be increased or given in divided doses (e.g., 3 times daily) due to faster clearance. Postpartum: reduce dose promptly to pre-pregnancy levels within 24 hours after delivery to avoid toxicity from narrowed volume of distribution.
No dose adjustment recommended for pregnancy; increased renal clearance in late pregnancy may require dose titration based on therapeutic drug monitoring.
AXOTAL (butalbital/acetaminophen/caffeine) is a combination analgesic for tension-type headaches. Butalbital is a barbiturate with addiction potential; limit use to less than 2 days per week to avoid medication overuse headache (MOH). Acetaminophen hepatic toxicity risk increases with chronic alcohol use or pre-existing liver disease. Caffeine may cause withdrawal headaches upon abrupt cessation.
Tencon is a combination analgesic containing acetaminophen, butalbital, and caffeine. It is indicated for tension headaches. Butalbital is a barbiturate with abuse potential; limit duration of use to avoid dependence. Acetaminophen hepatotoxicity risk increases with doses >4 g/day or in patients with hepatic impairment. Caffeine may exacerbate anxiety or insomnia. Monitor for signs of barbiturate withdrawal (anxiety, tremor, seizures) if discontinued abruptly after prolonged use.
Do not exceed 4 tablets per day to avoid acetaminophen overdose (max 4000 mg/day).,Avoid alcohol while taking this medication due to risk of liver damage.,This drug can be habit-forming; use only as prescribed for headache attacks, not for prophylaxis.,May cause drowsiness or dizziness; avoid driving or operating machinery until you know how you react.,Discontinue and seek medical help if you experience signs of liver injury (jaundice, dark urine) or allergic reaction (rash, swelling).,Caffeine content may interfere with sleep or exacerbate anxiety; limit other caffeine sources.
Take exactly as prescribed; do not exceed recommended dose.,Avoid alcohol while taking this medication due to increased liver damage risk.,Do not take with other products containing acetaminophen (e.g., Tylenol, cold medicines).,This drug can be habit-forming; do not use longer than directed.,May cause drowsiness or dizziness; avoid driving or operating heavy machinery until you know how it affects you.,Limit caffeine intake from other sources (coffee, tea, soda) to prevent overstimulation.,If you miss a dose, take it as soon as you remember; do not double the next dose.,Store at room temperature away from moisture and heat.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about AXOTAL vs TENCON, answered by our medical review team.
AXOTAL is a Barbiturate Combination Analgesic that works by Axotal contains butalbital, a barbiturate that enhances GABA-A receptor activity, and acetaminophen, an analgesic and antipyretic whose mechanism is not fully understood but may involve COX inhibition and activation of descending serotonergic pathways.. TENCON is a Barbiturate combination analgesic that works by 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.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between AXOTAL and TENCON depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of AXOTAL is: Each tablet: butalbital 50 mg, acetaminophen 300-500 mg, caffeine 40 mg. 1-2 tablets orally every 4 hours as needed, not exceeding 6 tablets per day.. The standard adult dose of TENCON is: 5 mg orally once daily, increased to 10 mg if needed after 2 weeks; maximum 20 mg daily.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between AXOTAL and TENCON in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. AXOTAL is classified as Category C. Pregnancy Category D. First trimester: Risk of cardiovascular malformations (e.g., Ebstein anomaly), neural tube defects, and oral clefts increased with lithium exposure. Second an. TENCON is classified as Category C. 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 nee. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.