Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACTIQ vs SELEXIPAG
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.
Selective agonist of the prostacyclin (IP) receptor, causing vasodilation and inhibition of platelet aggregation via increased c AMP levels.
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
Treatment of pulmonary arterial hypertension (PAH; WHO Group I) to improve exercise capacity and delay clinical worsening.
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.
Oral, starting dose 200 mcg twice daily, titrated in increments of 200 mcg twice daily at weekly intervals as tolerated to a maximum of 1600 mcg twice daily.
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.
Terminal elimination half-life is approximately 6–8 hours following intravenous administration; with oral administration, the effective half-life is ~6–9 hours due to enterohepatic recirculation; clinical context: dosing every 6 hours is required to maintain therapeutic plasma concentrations.
Primarily hepatic via CYP3A4 to inactive metabolites (norfentanyl, despropionylfentanyl, hydroxyfentanyl) and other metabolites; <7% excreted unchanged in urine.
Primarily metabolized by CYP2C8 and CYP3A4; minor contribution from UGT1A3, UGT2B7, and CYP2C9.
Primarily renal as metabolites (about 75% as metabolites, <10% unchanged). Fecal excretion accounts for <9%. Biliary excretion is minor.
Primarily hepatic metabolism (approximately 97% of dose) via CYP2C8 and CYP3A4; biliary/fecal excretion of metabolites accounts for ~77% of total clearance; renal excretion <1% as unchanged drug.
Fentanyl is 80–85% bound to plasma proteins (primarily albumin and α1-acid glycoprotein).
Approximately 99% bound to plasma proteins, primarily albumin.
Approximately 4 L/kg (range 3–6 L/kg); large Vd indicates extensive tissue distribution and redistribution contributing to short duration.
Volume of distribution at steady state is approximately 1.7 L/kg (range 1.1–2.5 L/kg), indicating extensive extravascular distribution.
Oral transmucosal: 50% (range 47–54%) relative to IV; variable and enhanced by rapid absorption through buccal mucosa.
Oral bioavailability is approximately 90% under fed conditions; absorption is delayed and reduced by high-fat meals, but overall systemic exposure is increased by ~30% compared to fasting.
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.
No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (e GFR <15 m L/min/1.73 m²) or on dialysis; use with caution.
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.
Contraindicated in Child-Pugh class C. For Child-Pugh class A or B, reduce starting dose to 200 mcg once daily and titrate cautiously; monitor closely.
Not approved for pediatric use; safety and efficacy not established in patients under 16 years.
Not approved for pediatric use; safety and efficacy not established.
Initiate at 100 mcg transmucosally; titrate slowly due to increased sensitivity and risk of respiratory depression. Monitor for adverse effects.
No specific dose adjustment recommended; initiate at 200 mcg twice daily and titrate based on tolerability, considering increased sensitivity and comorbidities.
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.
Not recommended for use in patients with severe hepatic impairment (Child-Pugh class C).
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.
Elderly patients may have increased exposure.,Patients with hepatic impairment: dose adjustment required for moderate impairment; avoid in severe impairment.,Concomitant use with strong CYP2C8 inhibitors (e.g., gemfibrozil) increases selexipag exposure by 11-fold; reduce dose.,Concomitant use with strong CYP3A4 inducers (e.g., rifampin) reduces exposure; monitor efficacy.,May cause headache, diarrhea, jaw pain, flushing, and nausea.
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.
Severe hepatic impairment (Child-Pugh class C).,Concomitant use with strong CYP2C8 inhibitors (e.g., gemfibrozil).
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.
Take with food to improve tolerance. Avoid grapefruit and grapefruit juice as they may increase selexipag plasma concentrations. No other significant food interactions known.
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.
Selexipag is contraindicated in pregnancy. Animal studies show increased post-implantation loss and reduced fetal weights. No adequate human data; based on its mechanism (IP receptor agonist), risk of fetal harm cannot be excluded, particularly in the first trimester.
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.
No data on selexipag in human milk. In animal studies, selexipag is excreted in rat milk. M/P ratio unknown. Breastfeeding is not recommended during treatment and for at least 7 days after last dose.
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.
Selexipag is not recommended in pregnancy. No dose adjustment data exist; pharmacokinetics in pregnancy have not been studied. Theoretical changes in volume of distribution and hepatic clearance may require monitoring, but no specific adjustments are established.
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.
Selexipag is a prostacyclin receptor (IP receptor) agonist used for pulmonary arterial hypertension (PAH). It is a prodrug that requires hepatic carboxylesterase 1 (CES1) activation. Monitor for signs of pulmonary edema suggestive of pulmonary veno-occlusive disease. Concurrent use with strong CYP2C8 inhibitors (e.g., gemfibrozil) increases exposure and is contraindicated. Dose adjustment needed in moderate hepatic impairment (Child-Pugh B). Thyroid abnormalities and bleeding risk are potential concerns.
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.
Take selexipag exactly as prescribed, typically twice daily with food to reduce gastrointestinal side effects.,Do not crush or chew tablets; swallow whole.,Common side effects include headache, diarrhea, nausea, jaw pain, and muscle aches; report persistent or severe symptoms.,Avoid grapefruit juice as it may increase drug levels.,Inform your doctor if you experience signs of bleeding (unusual bruising, nosebleeds) or thyroid issues (fatigue, weight changes).,Do not stop abruptly without medical advice; sudden discontinuation may worsen PAH.,If you are taking gemfibrozil or other CYP2C8 inhibitors, discuss with your doctor as combination is contraindicated.,Women of childbearing potential should use effective contraception; discuss pregnancy planning with your doctor.
No interactions on record
"Hydrochlorothiazide, a thiazide diuretic, reduces blood pressure primarily by decreasing plasma volume and cardiac output, while Selexipag, a prostacyclin receptor agonist, causes vasodilation and inhibits platelet aggregation. Their concomitant use results in additive hypotensive effects, increasing the risk of symptomatic hypotension, dizziness, and syncope. This interaction is particularly significant in patients with compromised baroreflex function or those receiving other antihypertensives."
"Selexipag, a prostacyclin receptor agonist used for pulmonary arterial hypertension, is primarily metabolized by CYP2C8 and CYP3A4. Abiraterone, a CYP3A4 inhibitor, may reduce the clearance of selexipag, leading to increased selexipag exposure. This can potentiate its adverse effects such as headache, flushing, and hypotension, though the impact on abiraterone levels is minimal due to abiraterone's multiple metabolic pathways."
"Bretylium, an antiarrhythmic agent, exerts sympatholytic effects by blocking norepinephrine release from adrenergic nerve terminals, leading to peripheral vasodilation and potential hypotension. Selexipag, a prostacyclin receptor agonist used for pulmonary arterial hypertension, also induces vasodilation via activation of IP receptors in vascular smooth muscle. When coadministered, the vasodilatory effects are additive, increasing the risk of clinically significant hypotension, which may manifest as dizziness, syncope, or impaired organ perfusion."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ACTIQ vs SELEXIPAG, answered by our medical review team.
ACTIQ is a Opioid Analgesic that works by Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.. SELEXIPAG is a Prostacyclin Receptor Agonist that works by Selective agonist of the prostacyclin (IP) receptor, causing vasodilation and inhibition of platelet aggregation via increased c AMP levels.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACTIQ and SELEXIPAG 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 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.. The standard adult dose of SELEXIPAG is: Oral, starting dose 200 mcg twice daily, titrated in increments of 200 mcg twice daily at weekly intervals as tolerated to a maximum of 1600 mcg twice daily.. 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 ACTIQ and SELEXIPAG 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. 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. SELEXIPAG is classified as Category C. Selexipag is contraindicated in pregnancy. Animal studies show increased post-implantation loss and reduced fetal weights. No adequate human data; based on its mechanism (IP recept. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.