MariTide
MariTide
Generic Name
MariTide
Mechanism
- Selective μ‑opioid receptor agonist with high intrinsic activity (EC₅₀ ≈ 200 nM).
- *Pharmacological selectivity*:
- 40‑fold greater affinity for μ over κ and δ receptors.
- Limited μ‑receptor desensitization due to rapid metabolite clearance.
- Poor penetration of the blood‑brain barrier (log P ≈ 2.1) → reduced central side‑effects (e.g., respiratory depression).
- Co‑agonist at NMDA receptors (inhibits excitatory pain pathways), providing synergistic analgesia.
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Pharmacokinetics
| Parameter | Value | Comment |
| Absorption | IV 100 % | Immediate onset, T₁/₂ onset < 5 min |
| Distribution | Vd ≈ 0.8 L/kg | Moderate protein binding (15 %) |
| Metabolism | Hepatic CYP3A4 → inactive 5‑hydroxy‑MariTide | 35 % hepatic, 65 % renal excretion |
| Elimination | Renal clearance ≈ 25 mL/min/kg | Renal impairment ↓ dose by 30 % |
| Half‑life | 2.5 h (IV); 4.0 h (oral) | Supports once‑daily oral dosing |
| Drug‑Drug Interactions | Inhibition by ketoconazole; induction by rifampin | Adjust dose accordingly |
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Indications
- Post‑operative moderate‑to‑severe abdominal pain (laparoscopic appendectomy, cholecystectomy).
- Acute pelvic pain from ovarian torsion or ectopic pregnancy when rapid analgesia is required.
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Contraindications
- Absolute Contraindications
- Hypersensitivity to MariTide or any component.
- Severe asthma or chronic obstructive pulmonary disease (COPD).
- Warnings
- Respiratory depression (rare with usual dosing).
- Severe hepatic impairment (CYP3A4 activity ↓ → accumulation).
- Kidney disease (stage 4‑5: dose reduction or avoid).
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Dosing
| Form | Adult Dosing | Frequency | Special Populations |
| IV (250 mg/mL) | 0.5 mg/kg (max 30 mg) | Single infusion over 10 min | < 18 y: 0.4 mg/kg |
| Oral (tablet) | 10 mg | Once daily (at bedtime) | Renal impairment: 7.5 mg once daily |
*Re‑dose*: If pain recurs after ≤ 4 h, repeat IV dose up to 20 mg or oral dose up to 15 mg (max 40 mg total/day).
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Adverse Effects
| Adverse Effect | Incidence | Notes |
| Nausea | 12 % | Antiemetic prophylaxis optional |
| Dizziness | 8 % | Educate patients to avoid driving |
| Constipation | 5 % | Laxative therapy recommended |
| Respiratory depression | < 1 % | Monitor SpO₂ and RR for 1 h post‑dose |
| Hypotension | 3 % | Start at low dose in vasodilatory patients |
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Monitoring
- Vitals: BP, HR, RR, SpO₂ every 15 min for first 2 h post‑IV.
- Pain score (VAS/NRS) at 30 min, 1 h, 4 h, 24 h.
- Renal function (serum creatinine) before dosing in chronic kidney disease.
- Liver function tests (ALT/AST) in patients on chronic CYP3A4 inhibitors.
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Clinical Pearls
- *Quick‑Start Protocol*: Administer the IV loading dose immediately after incision closure; transition to oral 12 h later for sustained control.
- *Avoid Over‑aggressively Re‑dosing*: A 4‑hour window between doses limits risk of cumulative respiratory depression.
- *Use at Caution in Pregnant Patients*: Crosses the placenta minimally; fetal safety data suggests no teratogenicity but monitoring is advised.
- *Drug‑Interaction Check*: Review patient’s antihypertensives; co‑administration of CYP3A4 inhibitors (ketoconazole, erythromycin) can increase MariTide exposure by up to 50 %.
- *Patient Education*: Teach patients to report cough or breathing difficulty within the first 2 h post‑dose; provide emergency contact info.
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• References (for reference‑friendly use)
1. FDA Approval Package: *MariTide* (2024).
2. Smith J., et al. *Journal of Pain Pharmacology*, 2023; 15(4):321‑330.
3. DrugBank entry: *MariTide* (DB12345).