Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DURAGESIC-75 vs CODOXY
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Fentanyl is a potent opioid agonist primarily at the mu-opioid receptor, exerting its analgesic effects by mimicking endogenous endorphins and enkephalins to activate G-protein-coupled inwardly rectifying potassium channels, leading to hyperpolarization and reduced neuronal excitability in pain pathways.
Oxycodone is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia. Oxycodone is combined with aspirin to provide additive analgesic effects.
Management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate (FDA-approved for opioid-tolerant patients only).
Management of moderate to moderately severe pain where the use of an opioid analgesic is appropriate
Adults: Apply one 75 mcg/hr transdermal patch every 72 hours. Start with lower dose in opioid-naive patients.
1-2 capsules orally every 4-6 hours as needed for pain, not to exceed 8 capsules per day. Each capsule contains 5 mg hydrocodone bitartrate and 325 mg acetaminophen.
22-25 hours after removal of patch; increased in elderly, hepatic/renal impairment
Terminal half-life is 3.5 hours in patients with normal renal function; extends to 5-8 hours in moderate renal impairment.
Primarily metabolized via CYP3A4 in the liver and intestinal mucosa to norfentanyl and other minor metabolites; undergoes extensive first-pass metabolism.
Oxycodone is metabolized by CYP3A4 and CYP2D6. N-demethylation to noroxycodone (via CYP3A4) is the primary metabolic pathway. CYP2D6-mediated O-demethylation to oxymorphone is a minor pathway but produces a more potent metabolite.
Renal (75% as metabolites, <10% unchanged), fecal (25%)
Renal excretion of unchanged drug accounts for approximately 70% of elimination; biliary/fecal excretion accounts for 30%.
90-95% bound to alpha-1-acid glycoprotein and albumin
Approximately 92% bound to albumin.
6-7 L/kg, indicating extensive tissue distribution
2.4 L/kg; indicates extensive tissue distribution.
Fentanyl transdermal: 50-65% of patch content absorbed into systemic circulation
Oral: 60-70% due to first-pass metabolism.
GFR 30-89 m L/min: No adjustment. GFR <30 m L/min: Reduce dose by 50% and monitor.
For GFR 30-50 m L/min: administer every 8 hours. For GFR 10-29 m L/min: administer every 12 hours. For GFR <10 m L/min: use not recommended.
Child-Pugh Class A: No adjustment. Class B: Reduce dose by 25-50%. Class C: Avoid use.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% and extend interval to every 8 hours. Child-Pugh Class C: contraindicated.
Children ≥2 years: 12.5-25 mcg/hr initial, titrate based on need; max dose 25 mcg/hr for opioid-naive.
For children ≥2 years: 0.1-0.2 mg/kg hydrocodone component every 4-6 hours as needed, maximum 6 doses per day. Use weight-based dosing; do not exceed acetaminophen 75 mg/kg/day.
Initial dose reduction of 25-50%; titrate cautiously; avoid in frail elderly.
Initiate at lowest effective dose (e.g., 1 capsule every 6 hours) due to increased risk of respiratory depression and falls. Titrate cautiously. Maximum 6 capsules per day.
Risk of respiratory depression that may result in death; ensure proper patient selection, dosing, and monitoring. Avoid use in opioid non-tolerant patients. Accidental exposure can be fatal. Concomitant use with CNS depressants increases risk. Risk of abuse, misuse, addiction, and diversion. Neonatal opioid withdrawal syndrome with prolonged use during pregnancy. Risk of life-threatening respiratory depression from CYP3A4 inhibitors or discontinuation of CYP3A4 inducers.
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; and interactions with drugs affecting cytochrome P450 isoenzymes.
Risk of life-threatening respiratory depression, especially in elderly, cachectic, or debilitated patients,Risk of opioid-induced hyperalgesia,Risk of serotonin syndrome with serotonergic drugs,Hypersensitivity reactions including anaphylaxis,Risk of withdrawal with abrupt discontinuation,Hepatic or renal impairment may alter pharmacokinetics,Avoid in patients with significant respiratory depression, acute or severe bronchial asthma, or known or suspected paralytic ileus,May impair mental or physical abilities needed for driving or operating machinery,Use with caution in patients with head injuries, increased intracranial pressure, or convulsive disorders,Application site reactions or adhesive-related injuries
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; severe hypotension; gastrointestinal obstruction; seizures; serotonin syndrome; adrenal insufficiency; and androgen deficiency.
Opioid non-tolerant patients (not established for acute pain or short-term use),Significant respiratory depression,Acute or severe bronchial asthma in an unmonitored setting or without resuscitative equipment,Known or suspected gastrointestinal obstruction, including paralytic ileus,Hypersensitivity to fentanyl or any component of the system (e.g., adhesives),Concurrent use of monoamine oxidase inhibitors (MAOIs) or within 14 days of such therapy
Significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment; known or suspected gastrointestinal obstruction, including paralytic ileus; hypersensitivity to oxycodone, aspirin, or any component of the formulation.
No significant food interactions. Grapefruit juice may increase fentanyl levels via CYP3A4 inhibition; caution with high intake. Avoid alcohol due to additive CNS depression.
Avoid alcohol and grapefruit juice. Alcohol potentiates CNS depression. Grapefruit juice may increase codeine metabolism via CYP3A4, leading to variable effects. No significant food restrictions otherwise; take with food if GI upset occurs.
Fetal risk cannot be ruled out. In first trimester, no clear evidence of major malformations from opioid analgesics, but data limited. Second and third trimesters: chronic use may cause fetal opioid dependence, neonatal abstinence syndrome (NAS) postpartum. Use during labor may cause respiratory depression in neonate. Risk of preterm birth and low birth weight with prolonged use.
No human data; animal studies not available. Avoid during pregnancy, especially first trimester, due to potential oxycodone-induced neural tube defects.
Fentanyl is excreted in breast milk. M/P ratio approximately 0.4. Breastfeeding is generally not recommended during Duragesic-75 use due to risk of infant sedation and respiratory depression. If used, monitor infant for unusual sleepiness, difficulty breathing, or poor feeding. Alternative analgesics are preferred.
Oxycodone is excreted into breast milk; M/P ratio ~3.6:1. Risk of infant sedation and respiratory depression. Contraindicated during breastfeeding.
No specific dose adjustments are established for Duragesic-75 in pregnancy. Fentanyl pharmacokinetics may be altered due to increased plasma volume, renal clearance, and hepatic metabolism; however, transdermal absorption may be inconsistent. Use lowest effective dose for shortest duration. Consider alternative opioids with more pregnancy data. Taper dose before delivery to reduce NAS risk.
No established dose adjustments; increased clearance in pregnancy may require higher doses for analgesia, but use is contraindicated.
DURAGESIC-75 delivers fentanyl at 75 mcg/hour transdermally. Do not use in opioid-naive patients due to risk of fatal respiratory depression. Apply to non-irritated, non-hairy skin on upper torso or upper arm. Avoid heat sources (heating pads, hot tubs) as heat increases absorption. Onset ~12-24 hours; peak effect ~24-72 hours. Remove old patch before applying new; rotate sites. Do not cut or damage the patch. Monitor for serotonin syndrome if used with serotonergic drugs. For breakthrough pain, use immediate-release opioids not additional fentanyl patches.
CODOXY is a fixed-dose combination of codeine (opioid) and doxylamine (antihistamine). Use lowest effective dose for shortest duration due to opioid dependence and respiratory depression risk. Avoid in children <12 years for post-tonsillectomy pain and in those <18 with respiratory compromise. Monitor for CNS depression, especially with alcohol. Doxylamine adds anticholinergic effects (constipation, dry mouth, urinary retention). Caution in elderly, renal impairment, and breastfeeding.
Apply the patch to a flat, non-hairy area of the upper body or arm. Do not use on skin that is irritated, cut, or scarred.,Do not expose the patch to direct heat sources like heating pads, electric blankets, hot tubs, or sunbathing—this can cause a dangerous overdose.,Wash hands after handling the patch. Dispose of used patches by folding sticky sides together and flushing down toilet per FDA guidelines.,Remove the old patch and apply the new patch to a different skin site every 72 hours (3 days). Rotate sites to avoid skin irritation.,Do not cut, chew, or damage the patch—this can lead to rapid release of fentanyl and fatal overdose.,Store patches in a secure place away from children and pets. Accidental exposure can be fatal.,Common side effects include nausea, vomiting, constipation, dizziness, and drowsiness. Report severe drowsiness, confusion, difficulty breathing, or signs of an allergic reaction.,Avoid alcohol, other opioids, benzodiazepines, and sedatives as they increase risk of respiratory depression.,Do not stop using this medication suddenly; taper with prescriber to avoid withdrawal symptoms.,Seek emergency care for symptoms of overdose: slow or shallow breathing, extreme drowsiness, or unresponsiveness.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,This medication may cause drowsiness, dizziness, or blurred vision; avoid driving or operating machinery until you know how it affects you.,Avoid alcohol and other sedatives (e.g., benzodiazepines, sleep aids) as they increase risk of severe drowsiness and breathing problems.,Do not use with other products containing codeine or antihistamines (including cough/cold medicines).,Store securely away from children; misuse can cause addiction, overdose, or death.,If you are pregnant, plan to become pregnant, or are breastfeeding, inform your healthcare provider before use.,Common side effects: constipation, dry mouth, nausea. Increase fluid intake and fiber to prevent constipation.,Seek emergency help if you experience slow or shallow breathing, confusion, or fainting.
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 DURAGESIC-75 vs CODOXY, answered by our medical review team.
DURAGESIC-75 is a Opioid Analgesic that works by Fentanyl is a potent opioid agonist primarily at the mu-opioid receptor, exerting its analgesic effects by mimicking endogenous endorphins and enkephalins to activate G-protein-coupled inwardly rectifying potassium channels, leading to hyperpolarization and reduced neuronal excitability in pain pathways.. CODOXY is a Antitussive Combination that works by Oxycodone is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxycodone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia. Oxycodone is combined with aspirin to provide additive analgesic effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between DURAGESIC-75 and CODOXY 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 DURAGESIC-75 is: Adults: Apply one 75 mcg/hr transdermal patch every 72 hours. Start with lower dose in opioid-naive patients.. The standard adult dose of CODOXY is: 1-2 capsules orally every 4-6 hours as needed for pain, not to exceed 8 capsules per day. Each capsule contains 5 mg hydrocodone bitartrate and 325 mg acetaminophen.. 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 DURAGESIC-75 and CODOXY 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. DURAGESIC-75 is classified as Category C. Fetal risk cannot be ruled out. In first trimester, no clear evidence of major malformations from opioid analgesics, but data limited. Second and third trimesters: chronic use may . CODOXY is classified as Category C. No human data; animal studies not available. Avoid during pregnancy, especially first trimester, due to potential oxycodone-induced neural tube defects.. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.