Butalbital, acetaminophen, caffeine, and codeine

Table 1 includes clinically significant drug interactions with Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules. Table 1: Clinically Significant Drug Interactions with Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules Inhibitors of CYP3A4 Clinical Impact: The concomitant use of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules with CYP3A4 inhibitors may result in an increase in codeine plasma concentrations with subsequently greater metabolism by cytochrome CYP2D6, resulting in greater morphine levels, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression, particularly when an inhibitor is added after a stable dose of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules is achieved [see Warnings and Precautions ( 5.7 )] . After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, it may result in lower codeine levels, greater norcodeine levels, and less metabolism via 2D6 with resultant lower morphine levels [see Clinical Pharmacology ( 12.3 )] , resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to codeine. Intervention: If concomitant use with CYP3A4 inhibitor is necessary, consider dosage reduction of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules until stable drug effects are achieved. Evaluate patients at frequent intervals for respiratory depression and sedation. If a CYP3A4 inhibitor is discontinued, consider increasing the Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules dosage until stable drug effects are achieved. Evaluate for signs of opioid withdrawal. Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir), grapefruit juice CYP3A4 Inducers Clinical Impact: The concomitant use of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules and CYP3A4 inducers can result in lower codeine levels, greater norcodeine levels, and less metabolism via 2D6 with resultant lower morphine levels [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence [see Warnings and Precautions ( 5.7 )] . After stopping a CYP3A4 inducer, as the effects of the inducer decline, the codeine plasma concentration may increase with subsequently greater metabolism by cytochrome CYP2D6, resulting in greater morphine levels [see Clinical Pharmacology ( 12.3 )] , which could increase or prolong both the therapeutic effects and adverse reactions, and may cause serious respiratory depression. Intervention: If concomitant use of a CYP3A4 inducer is necessary, evaluate the patient at frequent intervals for reduced efficacy and signs of opioid withdrawal and consider increasing the Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules dosage as needed. If a CYP3A4 inducer is discontinued, consider lowering Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules dosage until stable drug effects are achieved. Evaluate patients at frequent intervals for signs of respiratory depression and sedation. Examples: Rifampin, carbamazepine, phenytoin Inhibitors of CYP2D6 Clinical Impact: Codeine is metabolized by CYP2D6 to form morphine. The concomitant use of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules and CYP2D6 inhibitors can increase the plasma concentration of codeine, but can decrease the plasma concentrations of active metabolite morphine, which could result in reduced analgesic efficacy or symptoms of opioid withdrawal, particularly when an inhibitor is added after a stable dose of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules is achieved [see Clinical Pharmacology ( 12.3 )] . After stopping a CYP2D6 inhibitor, as the effects of the inhibitor decline, the codeine plasma concentration will decrease but the active metabolite morphine plasma concentration will increase, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression [see Clinical Pharmacology ( 12.3 )] . Intervention: If concomitant use with a CYP2D6 inhibitor is necessary, or if a CYP2D6 inhibitor is discontinued after concomitant use, consider dosage adjustment of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules and evaluate patients at frequent intervals. If concomitant use with CYP2D6 inhibitors is necessary, evaluate the patient for reduced efficacy or signs and symptoms of opioid withdrawal and consider increasing the dosage of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules as needed. After stopping use of a CYP2D6 inhibitor, consider reducing the dosage of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules and evaluate the patient at frequent intervals for signs and symptoms of respiratory depression or sedation. Examples: paroxetine, fluoxetine, bupropion, quinidine Benzodiazepines and Other Central Nervous System (CNS) Depressants Clinical Impact: Due to additive pharmacologic effect, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Intervention: Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Inform patients and caregivers of this potential interaction and educate them on the signs and symptoms of respiratory depression (including sedation). If concomitant use is warranted, consider recommending or prescribing an opioid overdose reversal agent [see Dosage and Administration ( 2.2 ), Warnings and Precautions ( 5.1 , 5.2 , 5.3 )]. Examples: Benzodiazepines and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids, alcohol. Serotonergic Drugs Clinical Impact: The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Intervention: If concomitant use is warranted, frequently evaluate the patient, particularly during treatment initiation and dose adjustment. Discontinue Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules if serotonin syndrome is suspected. Examples: Selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect the serotonin neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue). Monoamine Oxidase Inhibitors (MAOIs) Clinical Impact: MAOI interactions with opioids may manifest as serotonin syndrome or opioid toxicity (e.g., respiratory depression, coma) [see Warnings and Precautions ( 5.11 )]. Intervention: Do not use Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules in patients taking MAOIs or within 14 days of stopping such treatment. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of other opioids (such as oxycodone, hydrocodone, oxymorphone, hydromorphone, or buprenorphine) to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression. Examples: phenelzine, tranylcypromine, linezolid Mixed Agonist/Antagonist and Partial Agonist Opioid Analgesics Clinical Impact: May reduce the analgesic effect of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules and/or precipitate withdrawal symptoms. Intervention: Avoid concomitant use. Examples: butorphanol, nalbuphine, pentazocine, buprenorphine Muscle Relaxants Clinical Impact: Codeine may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression. Intervention: Because respiratory depression may be greater than otherwise expected, decrease the dosage of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules and/or the muscle relaxant as necessary. Due to the risk of respiratory depression with concomitant use of skeletal muscle relaxants and opioids, consider recommending or prescribing an opioid overdose reversal agent [see Dosage and Administration ( 2.2 ), Warnings and Precautions ( 5.2 , 5.3 )]. Examples: cyclobenzaprine, metaxalone Diuretics Clinical Impact: Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Intervention: Evaluate patients for signs of diminished diuresis and/or…

8.1 Pregnancy Risk Summary Use of opioid analgesics for an extended period of time during pregnancy may cause neonatal opioid withdrawal syndrome [see Warnings and Precautions ( 5.4 )] . Available data with Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage. There are risks to the mother and infant associated with use of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules for an extended period of time during pregnancy (see Clinical Considerations).

Animal reproduction studies have not been conducted with the combination of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules or with butalbital alone. In animal reproduction studies, codeine administration during organogenesis has been shown to produce delayed ossification in the offspring of mice at 2.8 times maximum recommended human dose (MRHD) of 180 mg/day, embryolethal and fetotoxic effects in the offspring of rats and hamsters at approximately 4 to 6 times the MRHD, and cranial malformations/cranioschisis in the offspring of hamsters between 2 and 8 times the MRHD.

Reproductive and developmental studies in rats and mice from the published literature identified adverse events at clinically relevant doses with acetaminophen. Treatment of pregnant rats with doses of acetaminophen approximately 2 times the maximum human daily dose (MHDD) showed evidence of fetotoxicity and increases in bone variations in the fetuses. In another study, necrosis was observed in the liver and kidney of both pregnant rats and fetuses at doses approximately 2 times the MHDD. In mice treated with acetaminophen at doses within the clinical dosing range, cumulative adverse effects on reproduction were seen in a continuous breeding study.

A reduction in number of litters of the parental mating pair was observed as well as retarded growth and abnormal sperm in their offspring and reduced birth weight in the next generation [ see Data ]. The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to20%, respectively.

Clinical Considerations Fetal/Neonatal Adverse Reactions Use of opioid analgesics for an extended period of time during pregnancy for medical or nonmedical purposes can result in…