Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ZOHYDRO ER vs ABSTRAL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Zohydro ER is a pure opioid agonist with relative selectivity for mu-opioid receptors, although it can interact with other opioid receptors at higher doses. Its primary therapeutic action is analgesia via binding to mu-opioid receptors in the central nervous system, leading to activation of descending inhibitory pathways and modulation of pain perception.
Fentanyl is a potent mu-opioid receptor agonist, producing analgesia and sedation by activating G-protein coupled opioid receptors in the central nervous system.
Zohydro ER is indicated for the management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate.
Management of breakthrough pain in cancer patients aged 18 and older who are already receiving and tolerant to around-the-clock opioid therapy for their underlying persistent cancer pain.
Initial: 20 mg orally every 24 hours; titrate in increments of 10-20 mg every 3-7 days as needed; maximum dose 200 mg every 24 hours.
For breakthrough pain in opioid-tolerant patients: initial dose 100 mcg sublingual tablet, titrate across strengths (100, 200, 300, 400, 600, 800 mcg) as needed; maximum 2 doses per episode, minimum 2 hours between episodes.
Terminal elimination half-life is approximately 10.6 hours (range 8-17 hours) due to extended-release formulation; immediate-release hydromorphone half-life is 2-3 hours. Clinically, steady-state is achieved after 3-5 days of dosing.
Terminal elimination half-life: 6-10 hours (mean 8 hours); prolonged in elderly and hepatic impairment
Hydrocodone is primarily metabolized by CYP3A4 and CYP2D6. CYP3A4 is the major enzyme responsible for N-demethylation to norhydrocodone, while CYP2D6 mediates O-demethylation to hydromorphone, a more potent opioid metabolite.
Hepatic metabolism primarily via CYP3A4; major metabolites include norfentanyl (inactive) and other minor metabolites.
Primarily renal excretion of hydromorphone-3-glucuronide (H3G, ~60%), unchanged hydromorphone (~15%), and other conjugates. Fecal excretion accounts for ~25%.
Renal: ~70% as metabolites (primarily fentanyl conjugates and norfentanyl), ~10% unchanged; Fecal: ~9%; Biliary: minimal
Approximately 20-30% bound to plasma proteins (albumin). Low binding minimizes drug interactions from protein displacement.
80-85% bound primarily to albumin and alpha-1-acid glycoprotein
Volume of distribution (Vd) is approximately 3.5 L/kg (range 2-5 L/kg), indicating extensive tissue distribution beyond total body water.
4-6 L/kg; large Vd indicates extensive tissue distribution
Oral bioavailability is ~50% (range 40-60%) due to first-pass metabolism; extended-release formulation provides consistent absorption over 12 hours.
Sublingual: 70-90% (mean 80%); buccal: 50-65%; oral: ~30% due to first-pass metabolism
GFR 30-59 m L/min: Initiate at 50% of usual dose and titrate cautiously; GFR <30 m L/min: Not recommended due to accumulation of metabolites.
No specific GFR-based dose adjustment recommended; use caution in severe renal impairment (Cr Cl <30 m L/min) due to potential accumulation of fentanyl.
Child-Pugh Class A: No adjustment; Child-Pugh Class B: Initiate at 50% of usual dose; Child-Pugh Class C: Not recommended.
For Child-Pugh Class A or B: no adjustment required; for Child-Pugh Class C: reduce dose and monitor closely for toxicity due to reduced clearance.
Not approved for pediatric patients; safety and efficacy not established.
Not approved for pediatric patients <18 years; safety and efficacy not established.
Initiate at 20 mg every 24 hours; titrate cautiously due to increased sensitivity and risk of respiratory depression.
Initiate at the lowest available dose (100 mcg) and titrate cautiously; elderly patients may have altered pharmacokinetics and increased sensitivity to fentanyl.
WARNING: ADDICTION, ABUSE, AND MISUSE; LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL INGESTION; NEONATAL OPIOID WITHDRAWAL SYNDROME; and RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS.
Risk of respiratory depression, addiction, abuse, and misuse; risk of accidental ingestion; risk of medication errors resulting in fatal overdose; life-threatening respiratory depression in opioid-non-tolerant patients; risk of opioid analgesic drug interactions with CNS depressants; risk of neonatal opioid withdrawal syndrome with prolonged use during pregnancy.
Addiction, Abuse, and Misuse,Life-Threatening Respiratory Depression,Neonatal Opioid Withdrawal Syndrome,Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants,Adrenal Insufficiency,Severe Hypotension,Gastrointestinal Effects: Constipation and Risk of Obstruction,Seizures in Patients with Seizure Disorders,Avoidance of Rapid Withdrawal,Driving and Operating Machinery
Respiratory depression, QT prolongation, serotonin syndrome, adrenal insufficiency, severe hypotension, seizures, biliary tract disease, gastrointestinal obstruction, withdrawal syndrome, and risk of overdose with alcohol or other CNS depressants.
Significant respiratory depression,Acute or severe bronchial asthma in an unmonitored setting or in absence of resuscitative equipment,Known or suspected gastrointestinal obstruction, including paralytic ileus,Hypersensitivity to hydrocodone or any other components of the product (e.g., anaphylaxis)
Hypersensitivity to fentanyl or any components; opioid-non-tolerant patients; acute or severe bronchial asthma; known or suspected gastrointestinal obstruction; concurrent use of MAOIs or within 14 days of discontinuation.
Take on an empty stomach (1 hour before or 2 hours after a meal) to prevent dose dumping. Avoid alcohol in any form (including medications containing alcohol, food prepared with alcohol, or alcoholic beverages) due to risk of rapid release and fatal overdose. Grapefruit juice may increase plasma hydrocodone levels; avoid concurrent use.
Avoid grapefruit and grapefruit juice during treatment as they inhibit CYP3A4, increasing fentanyl exposure. No other significant food interactions; however, avoid alcohol due to additive CNS depressant effects. Maintain consistent meal timing relative to dosing to minimize variability.
ZOHYDRO ER contains hydrocodone, a Schedule II opioid. First trimester: Increased risk of neural tube defects (OR 2.2) and congenital heart defects (OR 1.8). Second and third trimesters: Chronic use may cause fetal opioid dependence, neonatal abstinence syndrome (NAS), and preterm birth. Avoid use during labor due to risk of neonatal respiratory depression.
FDA Pregnancy Category C. First trimester: Inadequate human data; opioid analgesics are not associated with major malformations but may cause neural tube defects at high doses in animal studies. Second trimester: No specific malformation risk. Third trimester: Prolonged use can cause neonatal opioid withdrawal syndrome (NOWS) and respiratory depression at birth.
Hydrocodone is excreted in breast milk with a relative infant dose of approximately 2-3% of maternal weight-adjusted dose. M/P ratio is approximately 1.0. Use with caution; monitor infant for drowsiness, respiratory depression, and poor feeding. Higher risk in CYP2D6 ultra-rapid metabolizers.
Minimal excretion into breast milk; M/P ratio not reported. Fentanyl is poorly absorbed orally, making significant infant exposure unlikely. Monitor infant for sedation, respiratory depression, and poor feeding. Avoid use in breastfeeding mothers with opioid dependence or high doses.
Pregnancy may alter hydrocodone pharmacokinetics. Increased clearance and volume of distribution in late pregnancy may require dose increases. However, due to teratogenicity and NAS risk, use only if benefits outweigh risks, with smallest effective dose and shortest duration. Avoid in third trimester; taper if possible before delivery.
Pregnancy increases clearance and volume of distribution, potentially reducing drug levels. Dose adjustments may be needed: initiate with lower doses and titrate to effect; consider increasing frequency or using breakthrough doses. Monitor for inadequate analgesia. Avoid abrupt discontinuation; taper if stopping.
Zohydro ER is an extended-release hydrocodone formulation that should be taken on an empty stomach (1 hour before or 2 hours after a meal) to avoid dose dumping. It is not bioequivalent to immediate-release hydrocodone; use caution when converting. Due to high alcohol content in the capsule (10% ethanol), patients with alcohol intolerance or liver disease may experience adverse effects. Prescribe only for opioid-tolerant patients requiring around-the-clock analgesia. Avoid in patients with significant respiratory depression, paralytic ileus, or MAOI use within 14 days.
ABSTRAL (fentanyl sublingual spray) is a transmucosal immediate-release fentanyl (TIRF) formulation indicated for breakthrough pain in opioid-tolerant patients. Due to high bioavailability (~70%) and rapid onset (peak plasma concentration at 15-30 minutes), initial titration must start with 100 mcg, with dose escalation based on efficacy and tolerability. Weight-based conversion from other fentanyl products is not valid; utilize the provided conversion table. Patients must have a rescue agent (e.g., naloxone) available. Concomitant use with CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) or inducers (e.g., rifampin, carbamazepine) requires dose adjustment. Avoid use in opioid-naïve patients due to risk of respiratory depression.
Swallow capsules whole; do not crush, chew, or dissolve as this can cause fatal overdose.,Do not consume alcohol while taking Zohydro ER; the capsule contains alcohol and additional alcohol may lead to rapid release and overdose.,Avoid grapefruit juice as it may increase hydrocodone levels.,Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Do not stop abruptly; withdrawal symptoms may occur. Taper under medical supervision.,Store securely out of reach of children and pets; dispose of unused medication via take-back programs.,Report severe drowsiness, slowed breathing, or difficulty breathing to a healthcare provider immediately.,Avoid driving or operating heavy machinery until you know how the medication affects you.
Use only for breakthrough cancer pain while on around-the-clock opioid therapy.,Do not switch from other fentanyl products based on dose; follow specific conversion instructions.,Spray entire dose into mouth; do not swallow or rinse for at least 10 minutes.,Store at room temperature, away from children and pets.,Dispose of unused units via drug take-back program or by flushing down toilet per FDA guidelines.,Never share this medication with others; death may occur.,Seek emergency if severe drowsiness, confusion, or slow breathing occurs.
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 ZOHYDRO ER vs ABSTRAL, answered by our medical review team.
ZOHYDRO ER is a Opioid Analgesic that works by Zohydro ER is a pure opioid agonist with relative selectivity for mu-opioid receptors, although it can interact with other opioid receptors at higher doses. Its primary therapeutic action is analgesia via binding to mu-opioid receptors in the central nervous system, leading to activation of descending inhibitory pathways and modulation of pain perception.. ABSTRAL is a Opioid Analgesic that works by Fentanyl is a potent mu-opioid receptor agonist, producing analgesia and sedation by activating G-protein coupled opioid receptors in the central nervous system.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ZOHYDRO ER and ABSTRAL depend on the specific clinical indication. These are both Opioid Analgesic agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ZOHYDRO ER is: Initial: 20 mg orally every 24 hours; titrate in increments of 10-20 mg every 3-7 days as needed; maximum dose 200 mg every 24 hours.. The standard adult dose of ABSTRAL is: For breakthrough pain in opioid-tolerant patients: initial dose 100 mcg sublingual tablet, titrate across strengths (100, 200, 300, 400, 600, 800 mcg) as needed; maximum 2 doses per episode, minimum 2 hours between episodes.. 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 ZOHYDRO ER and ABSTRAL 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. ZOHYDRO ER is classified as Category C. ZOHYDRO ER contains hydrocodone, a Schedule II opioid. First trimester: Increased risk of neural tube defects (OR 2.2) and congenital heart defects (OR 1.8). Second and third trime. ABSTRAL is classified as Category C. FDA Pregnancy Category C. First trimester: Inadequate human data; opioid analgesics are not associated with major malformations but may cause neural tube defects at high doses in a. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.