What medication should be prescribed for a stable patient with a small, unruptured ectopic pregnancy?

Answer: Methotrexate

For a hemodynamically stable patient with unruptured ectopic pregnancy, the provider should prescribe Methotrexate (Option A), not Paracetamol. 1

Clinical Rationale

Methotrexate is the definitive medical treatment for unruptured ectopic pregnancy in appropriately selected patients, while paracetamol is merely an analgesic that does not address the underlying life-threatening condition. 1, 2

Patient Selection Criteria for Methotrexate

Before prescribing methotrexate remotely, the provider must verify the following eligibility criteria:

• Hemodynamic stability - Patient must have stable vital signs 1
• Ectopic mass size ≤3.5 cm in greatest dimension on ultrasound 1, 2
• β-hCG levels preferably ≤5,000 mIU/mL - Higher levels significantly increase failure rates (22-27%) and rupture risk (5-7%) 1, 2
• No embryonic cardiac activity on ultrasound (relative contraindication if present) 1
• Minimal hemoperitoneum (<100 mL if present) 3
• No contraindications including active liver/kidney disease, immunodeficiency, peptic ulcer disease, or bone marrow suppression 1

Critical Safety Concern: Remote Prescribing

The American College of Emergency Physicians explicitly recommends that patients whose hemodynamic stability, ultrasound findings, and laboratory results cannot be verified should be considered for surgical management instead of remote methotrexate prescription. 1

This is a critical pitfall to avoid - prescribing methotrexate without direct patient assessment and confirmed eligibility criteria exposes the patient to:

• 15-23% treatment failure rate requiring delayed surgery 1
• 0.5-19% rupture risk during treatment 1, 2
• Potential hemodynamic compromise from delayed rupture 2

Treatment Protocol (If Criteria Met)

• Dose: Methotrexate 50 mg/m² intramuscular injection 1, 4
• Pre-treatment labs required: Complete blood count with differential and platelets, liver enzymes, renal function tests 1, 4
• Follow-up monitoring: Serial β-hCG levels on days 4 and 7, then weekly until undetectable 1
• Second dose indication: If β-hCG fails to decrease ≥15% between days 4-7 5

Expected Treatment Outcomes

• Success rate: 65-96% for appropriately selected patients 1, 3
• Mean resolution time: 32 days for single dose, 58 days if multiple doses needed 3
• Rupture rate: 0.5-9% even in selected patients 1

Mandatory Patient Instructions

Patients must be instructed to return immediately for:

• Severe abdominal pain (may indicate rupture) 1, 4
• Shoulder pain (diaphragmatic irritation from hemoperitoneum) 1, 4
• Heavy vaginal bleeding 1, 4
• Signs of hemodynamic instability (dizziness, syncope, tachycardia) 1, 4

Drug Interactions and Contraindications

• Avoid folic acid supplements - counteracts methotrexate action 1, 4
• Avoid NSAIDs and aspirin - potentially lethal interactions 1, 4
• Discontinue breastfeeding immediately - wait ≥3 months after last dose before resuming 1, 4
• Rh-negative patients: Administer anti-D immunoglobulin 1, 4

When Surgery is Indicated Instead

Surgical management should be chosen over methotrexate if:

• Ectopic mass >3.5 cm (absolute contraindication at 4 cm) 2
• β-hCG >5,000 mIU/mL 1, 2
• Embryonic cardiac activity present 1, 2
• Hemodynamic instability 1
• Patient unable to comply with close follow-up 1
• Provider cannot directly verify eligibility criteria 1

Common Pitfall

Do not prescribe methotrexate based solely on a phone call stating the patient is "stable" without confirmed ultrasound findings, laboratory values, and direct assessment. 1 The 19-35% failure rate in suboptimal candidates, combined with rupture risk during the prolonged monitoring period, makes inappropriate patient selection dangerous. 2