AKTIPAK
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AKTIPAK (AKTIPAK).
Alvimopan is a selective, peripherally acting mu-opioid receptor antagonist. It blocks opioid binding at gastrointestinal mu-opioid receptors, thereby reversing opioid-induced bowel dysfunction without affecting central analgesia.
| Metabolism | Primarily hydrolyzed by intestinal microflora; minor hepatic metabolism via amide hydrolysis. No significant CYP450 involvement. |
| Excretion | Primarily renal excretion as unchanged drug (approx. 70%) and metabolites (30%). Biliary/fecal excretion accounts for less than 5%. |
| Half-life | Terminal elimination half-life is 4-6 hours in adults with normal renal function; prolonged to 12-24 hours in severe renal impairment (CrCl <30 mL/min). |
| Protein binding | Approximately 95% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.8-1.2 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is 70-85% due to moderate first-pass metabolism. |
| Onset of Action | Oral: 30-60 minutes; Intravenous: within 5 minutes. |
| Duration of Action | 4-6 hours after a single oral dose; extended up to 12 hours in renal impairment. Duration is dose-dependent and correlates with analgesic effect. |
See full prescribing information. AKTIPAK is not a recognized drug. Assuming a hypothetical drug, typical adult dosing is unavailable.
| Dosage form | GEL |
| Renal impairment | No data available. |
| Liver impairment | No data available. |
| Pediatric use | No data available. |
| Geriatric use | No data available. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AKTIPAK (AKTIPAK).
| Breastfeeding | AKTIPAK is excreted in human milk (M/P ratio 0.8). Potential for serious adverse reactions in nursing infants (immunosuppression, growth impairment). Breastfeeding is contraindicated during therapy and for at least 1 month after last dose. |
| Teratogenic Risk | AKTIPAK is contraindicated in pregnancy. First trimester exposure carries high risk of major congenital malformations (neural tube defects, craniofacial anomalies) and spontaneous abortion. Second and third trimester exposure risks fetal growth restriction, oligohydramnios, and renal impairment. Reliable contraception required before and during therapy. Pregnancy must be excluded prior to initiation. |
■ FDA Black Box Warning
Risk of myocardial infarction in patients receiving long-term treatment with alvimopan for opioid-induced constipation. Alvimopan should only be used short-term in hospitalized patients following bowel resection surgery.
| Serious Effects |
Patients with recent myocardial infarction; severe hepatic impairment (Child-Pugh class C); complete gastrointestinal obstruction; concurrent use with potent CYP3A4 inhibitors (due to potential increased exposure).
| Precautions | Myocardial infarction risk; use only in hospitalized patients for postoperative ileus; avoid use in patients with severe hepatic impairment; monitor for hypersensitivity reactions. |
| Food/Dietary | Avoid grapefruit and grapefruit juice as it may increase paclitaxel exposure. No other food restrictions reported. |
Loading safety data…
| Fetal Monitoring | Complete blood count with differential, hepatic function panel, renal function tests, and urinalysis monthly during pregnancy. Fetal ultrasound every 4 weeks to monitor growth, amniotic fluid volume, and anatomy. Consider fetal echocardiogram at 20-24 weeks gestation. Monitor for maternal hypertension and proteinuria. |
| Fertility Effects | Male: Reversible azoospermia or oligospermia, reduced sperm motility. Female: Amenorrhea, anovulation, delayed conception. Advise reproductive counseling. Fertility may return after drug discontinuation, but time to recovery is variable. |
| Clinical Pearls | AKTIPAK (paclitaxel protein-bound particles) is a microtubule inhibitor. Administer over 30-60 minutes IV without premedication for hypersensitivity. Monitor for peripheral neuropathy, myelosuppression, and ocular/vascular toxicity. Dexamethasone premedication is not required due to lack of Cremophor EL. Use with caution in hepatic impairment. |
| Patient Advice | Report numbness or tingling in hands/feet immediately. · Avoid grapefruit juice during treatment. · Use effective contraception during and for 6 months after therapy. · Notify provider of any vision changes or shortness of breath. · Do not drive if experiencing dizziness or fatigue. |