Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MS CONTIN vs ACTIQ
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Mu-opioid receptor agonist; binds to mu-opioid receptors in the CNS, modulating pain perception and emotional response to pain.
Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.
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 16 and older who are already receiving and tolerant to opioid therapy for their underlying persistent cancer pain
Oral: 15-30 mg every 8-12 hours; adjust based on pain severity and prior opioid use. Extended-release tablets must be swallowed whole; do not crush or chew. For opioid-naïve patients, start at 15 mg every 12 hours.
200 mcg transmucosally, titrated upward as needed; initial dose for opioid-tolerant patients is 200 mcg, with additional doses possible after 15 minutes if needed. Maximum 4 doses per episode. At least 4 hours between episodes.
Terminal elimination half-life: 11-13 hours (range 8-24 hours). In elderly or hepatic impairment, half-life may be prolonged; acute dosing half-life ~2-4 hours.
Terminal half-life 0.83–2 hours (mean 1.3 h) in adults; note that context: transmucosal absorption leads to rapid onset but short duration; half-life is not correlated with clinical effect due to oral transmucosal route and rapid redistribution.
Hepatic via CYP3A4 and to a lesser extent CYP2D6; major metabolites include morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G).
Primarily hepatic via CYP3A4 to inactive metabolites (norfentanyl, despropionylfentanyl, hydroxyfentanyl) and other metabolites; <7% excreted unchanged in urine.
Renal: ~90% (mostly as morphine-3-glucuronide and morphine-6-glucuronide, with ~10% as unchanged morphine); Fecal: <10%
Primarily renal as metabolites (about 75% as metabolites, <10% unchanged). Fecal excretion accounts for <9%. Biliary excretion is minor.
30-35% bound to albumin.
Fentanyl is 80–85% bound to plasma proteins (primarily albumin and α1-acid glycoprotein).
1.0-4.7 L/kg (mean ~3.5 L/kg), indicating extensive tissue distribution.
Approximately 4 L/kg (range 3–6 L/kg); large Vd indicates extensive tissue distribution and redistribution contributing to short duration.
Oral: 20-40% (first-pass metabolism); Rectal: ~50%; IV: 100%.
Oral transmucosal: 50% (range 47–54%) relative to IV; variable and enhanced by rapid absorption through buccal mucosa.
e GFR 30-59 m L/min: Administer 75% of usual dose every 12 hours. e GFR 15-29 m L/min: Administer 50% of usual dose every 12 hours. e GFR <15 m L/min: Administer 50% of usual dose every 12 hours, consider alternative. For dialysis patients: not recommended (accumulation of toxic metabolites).
No specific GFR-based dose adjustment recommended; use with caution in severe renal impairment (Cr Cl < 30 m L/min) and consider dose reduction due to potential accumulation.
Child-Pugh Class A: No adjustment needed. Child-Pugh Class B: Reduce dose by 25% and increase dosing interval to every 12 hours. Child-Pugh Class C: Reduce dose by 50% and consider alternative therapy.
Child-Pugh Class A/B: No adjustment. Child-Pugh Class C: Reduce initial dose to 100 mcg and titrate slowly; monitor closely for prolonged effects.
Not approved for use in pediatric patients; safety and efficacy not established. For opioid-tolerant adolescents (≥13 years) transitioning from immediate-release to extended-release: use conversion guidelines, starting at the calculated equianalgesic dose, rounding down, with close monitoring.
Not approved for pediatric use; safety and efficacy not established in patients under 16 years.
Start at lowest possible dose (e.g., 15 mg every 12 hours). Titrate cautiously due to increased sensitivity, decreased renal/hepatic function, and risk of falls, respiratory depression, and delirium. Monitor for accumulation. Consider avoidance or alternative in frail elderly.
Initiate at 100 mcg transmucosally; titrate slowly due to increased sensitivity and risk of respiratory depression. Monitor for adverse effects.
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants.
Risk of respiratory depression, addiction, abuse, and misuse; accidental ingestion can be fatal; concomitant use with benzodiazepines or CNS depressants may cause profound sedation, respiratory depression, coma, and death; not for use in opioid non-tolerant patients; risk of neonatal opioid withdrawal syndrome with prolonged use during pregnancy; serious, life-threatening, or fatal respiratory depression may occur even at recommended doses.
Respiratory depression; additive CNS effects with other depressants; hypotension; gastrointestinal obstruction; seizure threshold; serotonin syndrome; adrenal insufficiency; severe renal/hepatic impairment; elderly/debilitated; pregnancy (prolonged use); avoid abrupt discontinuation.
Risk of respiratory depression; addiction, abuse, and misuse; interactions with CNS depressants; serotonin syndrome; adrenal insufficiency; severe hypotension; seizures; withdrawal; use in patients with head injuries, increased intracranial pressure, biliary tract disease, pancreatitis; risk of choking with lozenge; oral mucosal irritation; dental caries; hypokalemia; hyponatremia; use in elderly, cachectic, or debilitated patients.
Significant respiratory depression; acute or severe bronchial asthma; known or suspected GI obstruction; hypersensitivity to morphine or any component; concurrent use of MAOIs or within 14 days.
Significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or without resuscitative equipment; known or suspected paralytic ileus; hypersensitivity to fentanyl or any component; opioid non-tolerant patients; management of acute or postoperative pain including headache/migraine, dental pain, or emergency department use.
Avoid alcohol and foods containing alcohol (e.g., some sauces, desserts). High-fat meals may slow absorption; take consistently with or without food to maintain steady effect. No specific food restrictions beyond alcohol.
No significant food interactions. Grapefruit juice may increase fentanyl levels, but specific studies with ACTIQ are lacking. Avoid alcohol, as it may increase sedation and respiratory depression risk.
First trimester: Limited data, but opioid use associated with neural tube defects (OR 1.5-2.0) and gastroschisis. Second/third trimester: Chronic use may cause fetal dependence, intrauterine growth restriction, premature labor. At delivery: Risk of neonatal opioid withdrawal syndrome (NOWS) in 60-80% of exposed neonates.
FDA Pregnancy Category C. First trimester: limited human data; animal studies show increased resorptions and fetal growth restriction. Second/third trimester: chronic use may cause neonatal opioid withdrawal syndrome; avoid use during labor due to risk of neonatal respiratory depression.
MS Contin (morphine) is excreted in breast milk with an M/P ratio of approximately 2.6. Relative infant dose is about 2-4% of maternal weight-adjusted dose. Avoid use in breastfeeding due to risk of infant sedation and respiratory depression; if necessary, monitor infant for drowsiness, difficulty feeding, and adequate weight gain.
Excreted in breast milk; M/P ratio not established. Limited data suggest low levels, but risk of infant sedation and respiratory depression. Avoid use while breastfeeding unless potential benefit outweighs risk.
Pregnancy may increase morphine clearance due to enhanced hepatic metabolism and renal elimination, potentially requiring dose adjustments. However, specific recommendations are not well-established. Use lowest effective dose and avoid during labor due to prolonged absorption and neonatal respiratory depression risk.
Due to increased plasma volume and hepatic metabolism in pregnancy, dose requirements may increase; adjust based on clinical response and tolerance. Avoid use during labor and delivery due to risk of neonatal respiratory depression; short-term use preferred.
MS Contin (morphine sulfate extended-release) is an opioid agonist indicated for around-the-clock management of moderate to severe pain requiring opioid treatment. Key pearls: 1) Do not crush, chew, or dissolve tablets; this can cause rapid release and fatal overdose. 2) Use with caution in patients with respiratory compromise, alcohol or benzodiazepine use, or obstructive sleep apnea. 3) Monitor for signs of constipation; prescribe bowel regimen prophylactically. 4) Tolerance and dependence develop; avoid abrupt discontinuation. 5) Use lowest effective dose for shortest duration. 6) Respiratory depression risk peaks after initial dosing and titration.
ACTIQ is a transmucosal immediate-release fentanyl formulation indicated for breakthrough cancer pain in opioid-tolerant patients. Initiate with the lowest strength (200 mcg) and titrate upward. Avoid use in opioid-naive patients due to risk of fatal respiratory depression. Place the unit between cheek and lower gum, not sublingually. Instruct patient not to bite or suck the unit. Monitor for sedation and respiratory depression. Multiple units may be used per episode if needed, but wait at least 4 hours before next episode. Dispose of partially used units by flushing down toilet.
Take exactly as prescribed; do not change dose or frequency without consulting your doctor.,Swallow tablets whole; do not crush, chew, or dissolve them.,Avoid alcohol and other sedatives (e.g., benzodiazepines) as they can increase risk of severe drowsiness, respiratory depression, and death.,If you miss a dose, skip it and take next dose at regular time; do not double dose.,Common side effects include constipation, nausea, drowsiness, and dizziness. Report severe constipation or difficulty breathing.,Do not stop suddenly without doctor guidance; withdrawal symptoms may occur.,Keep out of reach of children and others; store in a secure place.,Do not share medication with others; it can cause fatal overdose.,Use caution when driving or operating machinery until you know how the medication affects you.,Notify doctor if you are pregnant, breastfeeding, or planning to become pregnant.
Only use ACTIQ if you are already taking regular around-the-clock opioid pain medicine and are tolerant to opioids.,Do not use ACTIQ for short-term pain like after surgery, headache, or dental pain.,Place the unit in your cheek pouch, not under your tongue. Do not chew or suck it.,If you need more than 4 units per day, contact your doctor as your dose may need adjustment.,Store ACTIQ in a safe place away from children, as accidental ingestion can be fatal.,Dispose of unused or partially used units by flushing them down the toilet.
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 MS CONTIN vs ACTIQ, answered by our medical review team.
MS CONTIN is a Opioid Analgesic that works by Mu-opioid receptor agonist; binds to mu-opioid receptors in the CNS, modulating pain perception and emotional response to pain.. ACTIQ is a Opioid Analgesic that works by Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MS CONTIN and ACTIQ 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 MS CONTIN is: Oral: 15-30 mg every 8-12 hours; adjust based on pain severity and prior opioid use. Extended-release tablets must be swallowed whole; do not crush or chew. For opioid-naïve patients, start at 15 mg every 12 hours.. The standard adult dose of ACTIQ is: 200 mcg transmucosally, titrated upward as needed; initial dose for opioid-tolerant patients is 200 mcg, with additional doses possible after 15 minutes if needed. Maximum 4 doses per episode. At least 4 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 MS CONTIN and ACTIQ 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. MS CONTIN is classified as Category C. First trimester: Limited data, but opioid use associated with neural tube defects (OR 1.5-2.0) and gastroschisis. Second/third trimester: Chronic use may cause fetal dependence, in. ACTIQ is classified as Category C. FDA Pregnancy Category C. First trimester: limited human data; animal studies show increased resorptions and fetal growth restriction. Second/third trimester: chronic use may cause. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.