Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACTIQ vs PEMFEXY
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.
Pemetrexed inhibits thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT), which are folate-dependent enzymes involved in nucleotide synthesis, leading to disruption of DNA and RNA synthesis.
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
Mesothelioma: In combination with cisplatin for the treatment of patients with malignant pleural mesothelioma whose disease is unresectable or who are otherwise not candidates for curative surgery.,Non-small cell lung cancer: First-line treatment of patients with locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) in combination with pembrolizumab and platinum chemotherapy.,Non-small cell lung cancer: Maintenance therapy for patients with locally advanced or metastatic non-squamous NSCLC whose disease has not progressed after four cycles of platinum-based first-line chemotherapy.,Non-small cell lung cancer: Treatment of patients with recurrent, metastatic non-squamous NSCLC after prior chemotherapy.
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.
500 mg/m2 intravenously over 10 minutes on day 1 of a 21-day cycle, in combination with cisplatin.
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 ~17 hours (range 13-26 hours) in patients with normal renal function; prolonged to >24 hours in renal impairment. Supports every-21-day dosing.
Primarily hepatic via CYP3A4 to inactive metabolites (norfentanyl, despropionylfentanyl, hydroxyfentanyl) and other metabolites; <7% excreted unchanged in urine.
Pemetrexed is primarily excreted unchanged in the urine; limited hepatic metabolism occurs via unspecified pathways. It is not significantly metabolized by CYP450 enzymes.
Primarily renal as metabolites (about 75% as metabolites, <10% unchanged). Fecal excretion accounts for <9%. Biliary excretion is minor.
Renal excretion (70-90% unchanged drug), biliary/fecal (<5%)
Fentanyl is 80–85% bound to plasma proteins (primarily albumin and α1-acid glycoprotein).
~95% 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.
Vd ~16 L/m² (approximately 0.4 L/kg); distributes into total body water with extensive tissue binding.
Oral transmucosal: 50% (range 47–54%) relative to IV; variable and enhanced by rapid absorption through buccal mucosa.
IV only; no oral bioavailability due to poor absorption and extensive first-pass metabolism.
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.
Cr Cl 45-59 m L/min: reduce dose to 400 mg/m2; Cr Cl 30-44 m L/min: reduce dose to 250 mg/m2; Cr Cl <30 m L/min: do not administer.
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.
No dosage adjustment required for Child-Pugh class A or B. For Child-Pugh class C, reduce dose by 50%.
Not approved for pediatric use; safety and efficacy not established in patients under 16 years.
Safety and efficacy not established in pediatric patients; not recommended.
Initiate at 100 mcg transmucosally; titrate slowly due to increased sensitivity and risk of respiratory depression. Monitor for adverse effects.
No dose adjustment based on age alone; monitor renal function and adjust according to Cr Cl.
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.
PEMFEXY can cause fetal harm when administered to a pregnant woman. Pemetrexed is contraindicated in patients who are pregnant or may become pregnant. Women of childbearing potential should be advised to avoid becoming pregnant during treatment with PEMFEXY.
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.
Myelosuppression: Pemetrexed can cause severe bone marrow suppression, including neutropenia, thrombocytopenia, and anemia. Monitor blood counts and adjust doses accordingly.,Renal toxicity: Pemetrexed is primarily eliminated renally; reduce dose in patients with creatinine clearance <45 m L/min. Not recommended for patients with Cr Cl <30 m L/min.,Cutaneous reactions: Severe dermatologic reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, have been reported; discontinue if severe.,Gastrointestinal toxicity: Diarrhea, nausea, and vomiting are common; administer premedication with corticosteroids and folic acid/vitamin B12 to reduce toxicity.,Pneumonitis: Interstitial pneumonitis has been reported; monitor for respiratory symptoms and discontinue if confirmed.,Radiation recall: Increased risk of radiation recall reactions in patients who have received prior radiotherapy.
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.
Pregnancy: Pemetrexed can cause fetal harm; contraindicated in pregnant women.,Severe hypersensitivity: History of severe hypersensitivity reaction to pemetrexed or any excipient.,Concomitant yellow fever vaccine: Increased risk of systemic vaccine reaction.,Breastfeeding: Discontinue nursing during treatment due to potential harm to the infant.
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.
No known food interactions. However, avoid grapefruit juice if taking concurrent CYP3A4 substrates due to potential enzyme inhibition? Not applicable for PEMFEXY. No dietary restrictions required.
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.
Category D: Positive evidence of human fetal risk. Avoid in pregnancy unless no safer alternative. First trimester: high risk of neural tube defects, craniofacial and limb malformations, growth restriction. Second/third trimester: increased risk of preterm delivery, low birth weight, fetal myelosuppression.
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.
Excreted in human milk. M/P ratio unknown. Potential for serious adverse reactions in nursing infants, including myelosuppression. Advise discontinue breastfeeding or the drug, considering importance to mother.
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.
Pregnancy-induced increases in plasma volume and renal clearance may decrease pemetrexed exposure. No formal dose recommendations; consider therapeutic drug monitoring if available. Use with folic acid and vitamin B12 supplementation to reduce toxicity.
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.
PEMFEXY (pembrolizumab) is a humanized monoclonal antibody that targets PD-1. Clinical pearls: 1) Administer as IV infusion over 30 minutes; do not shake vial. 2) Monitor for immune-mediated adverse reactions such as pneumonitis, colitis, hepatitis, endocrinopathies, and nephritis. 3) Corticosteroids may be used to manage severe immune-related adverse events. 4) Do not coadminister with systemic immunosuppressants unless managing toxicity. 5) No dose adjustment required for renal or mild hepatic impairment. 6) Check PD-L1 expression for NSCLC appropriateness.
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.
Inform your healthcare provider about any history of autoimmune disease, organ transplant, or lung problems.,Report new or worsening symptoms such as cough, chest pain, shortness of breath, diarrhea, abdominal pain, blood in stool, jaundice, severe fatigue, weight changes, or skin rash.,Do not receive live vaccines during treatment.,Avoid pregnancy while on treatment; use effective contraception.,Report signs of infusion reaction such as fever, chills, flushing, or hypotension during and after infusion.
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 ACTIQ vs PEMFEXY, 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.. PEMFEXY is a Antineoplastic Antifolate that works by Pemetrexed inhibits thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT), which are folate-dependent enzymes involved in nucleotide synthesis, leading to disruption of DNA and RNA synthesis.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACTIQ and PEMFEXY 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 PEMFEXY is: 500 mg/m2 intravenously over 10 minutes on day 1 of a 21-day cycle, in combination with cisplatin.. 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 PEMFEXY 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. PEMFEXY is classified as Category C. Category D: Positive evidence of human fetal risk. Avoid in pregnancy unless no safer alternative. First trimester: high risk of neural tube defects, craniofacial and limb malforma. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.