SARISOL NO. 2
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SARISOL NO. 2 (SARISOL NO. 2).
SARISOL NO. 2 contains butalbital, acetaminophen, and caffeine. Butalbital is a barbiturate that enhances GABA-A receptor activity, producing sedation. Acetaminophen inhibits cyclooxygenase (COX) enzymes centrally, reducing pain and fever. Caffeine is a CNS stimulant that antagonizes adenosine receptors.
| Metabolism | Butalbital: hepatic via CYP2C19; Acetaminophen: hepatic via CYP3A4, CYP2E1, and glucuronidation/sulfation; Caffeine: hepatic via CYP1A2. |
| Excretion | Renal excretion of unchanged drug and metabolites; 70% renal, 30% biliary/fecal. |
| Half-life | Terminal elimination half-life is 12-15 hours; prolonged in hepatic impairment. |
| Protein binding | 85% bound to albumin. |
| Volume of Distribution | 0.8 L/kg; indicates moderate tissue distribution. |
| Bioavailability | Oral: 90%. |
| Onset of Action | Oral: 30-60 minutes. |
| Duration of Action | 4-6 hours; sustained in hepatic dysfunction. |
Butalbital 50 mg, acetaminophen 325 mg, and caffeine 40 mg per tablet; 1 to 2 tablets orally every 4 hours as needed, not to exceed 6 tablets per day.
| Dosage form | TABLET |
| Renal impairment | CrCl < 50 mL/min: Avoid use or extend dosing interval; acetaminophen accumulation risk. CrCl < 10 mL/min: Not recommended. |
| Liver impairment | Child-Pugh Class A: Caution; avoid if possible. Child-Pugh Class B or C: Contraindicated due to acetaminophen hepatotoxicity and butalbital metabolism. |
| Pediatric use | Not recommended for use in children (safety and efficacy not established). |
| Geriatric use | Initiate with 1 tablet every 4 hours; monitor for CNS depression, confusion, and acetaminophen toxicity; avoid in frail elderly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SARISOL NO. 2 (SARISOL NO. 2).
| Breastfeeding | Butorphanol is excreted in breast milk. The M/P ratio is unknown. Due to potential for infant respiratory depression and withdrawal, breastfeeding is not recommended during therapy and for 48 hours after last dose. |
| Teratogenic Risk | SARISOL NO. 2 (butorphanol tartrate) is a mixed agonist-antagonist opioid. In the first trimester, no adequate studies; use only if clearly needed. In the second and third trimesters, prolonged use may lead to neonatal opioid withdrawal syndrome (NOWS). Avoid during labor if preterm or when respiratory depression risk is high. Not recommended for prolonged use in pregnancy. |
■ FDA Black Box Warning
Acetaminophen may cause severe hepatic injury at high doses or with chronic use. Butalbital can be habit-forming; use with caution in patients with substance abuse history.
| Serious Effects |
Hypersensitivity to any component; porphyria; severe hepatic impairment; acute or chronic alcoholism; concurrent MAO inhibitors (relative).
| Precautions | Hepatotoxicity with acetaminophen overdose; sedation and respiratory depression with butalbital; potential for dependence/withdrawal; avoid concurrent alcohol or CNS depressants; caution in hepatic/renal impairment. |
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| Fetal Monitoring | Monitor maternal respiratory rate, sedation level, and blood pressure. Fetal heart rate monitoring is recommended during labor. Assess for signs of neonatal respiratory depression if given near delivery. |
| Fertility Effects | No specific human reproductive studies exist. In animal studies, no adverse effects on fertility were observed. However, opioid use may impair fertility in both males and females through hormonal alterations. |