What are the typical premedication doses and administration routes, particularly oral (po), for procedures?

Premedication Doses and Oral Administration for Procedures

Antiemetic Premedication for Chemotherapy

For highly emetogenic chemotherapy (Grade 4), administer dexamethasone 20 mg orally, granisetron 1 mg orally, and lorazepam 1 mg orally every 1 hour as needed, given as pretreatment before the procedure. 1

High Emetogenic Potential (Grade 4)

• Dexamethasone 20 mg PO administered as pretreatment 1
• Granisetron 1 mg PO as pretreatment 1
• Lorazepam 1 mg PO every 1-2 hours as needed (avoid if excessive drowsiness present) 1
• Alternative regimen: Ondansetron 16 mg PO can be used instead of granisetron 1
• For delayed emesis: Dexamethasone 4-8 mg PO twice daily for maximum of 4 days 1

Moderate Emetogenic Potential (Grade 3)

• Dexamethasone 20 mg PO as pretreatment 1
• Ondansetron 16 mg PO as pretreatment 1
• Dexamethasone 4 mg PO twice daily for 2 days (optional for delayed symptoms) 1

Low Emetogenic Potential (Grade 1-2)

• Dexamethasone 20 mg PO (optional) 1
• Prochlorperazine 10 mg PO as pretreatment (optional) 1
• Prochlorperazine 10 mg PO every 6 hours as needed for breakthrough symptoms 1

Premedication for Infusion Reactions

For monoclonal antibodies with high infusion reaction risk, administer premedication 30 minutes to 2 hours before infusion: paracetamol 1000 mg orally, diphenhydramine 50 mg orally or IV, and prednisolone 50-100 mg IV depending on the agent. 1

Standard Infusion Reaction Prophylaxis

• Paracetamol 650-1000 mg PO given 1 hour before infusion 1
• Diphenhydramine 25-50 mg PO or IV (or equivalent antihistamine) 1
• Methylprednisolone 100 mg IV (or equivalent corticosteroid) for high-risk agents 1

Agent-Specific Protocols

Ofatumumab:

• Paracetamol 1000 mg PO 30 minutes to 2 hours before 1
• Diphenhydramine 50 mg PO or IV (or cetirizine 10 mg) 1
• Prednisolone 50 mg IV (previously untreated) or 100 mg IV (refractory disease) 1

Rituximab:

• Paracetamol PO plus diphenhydramine PO before infusion 1
• Slow initial infusion rate recommended 1

Cetuximab:

• Methylprednisolone 100 mg IV (or equivalent) 1
• Paracetamol 650-1000 mg PO 1
• Diphenhydramine 25-50 mg PO or IV 1
• All given 1 hour before every infusion 1

Postoperative Pain Management Premedication

Administer dexamethasone 8 mg IV at induction of anesthesia to reduce postoperative pain in adults undergoing major surgery. 1

Corticosteroid Premedication

• Dexamethasone 8 mg IV for adults at induction 1
• Dexamethasone 0.15 mg/kg for children 1
• Reduces postoperative pain and nausea/vomiting 1

Ketamine Premedication (High-Risk Procedures)

• Ketamine 0.5 mg/kg IV maximum after anesthesia induction 1
• Continuous infusion 0.125-0.25 mg/kg/hour during surgery 1
• Stop 30 minutes before end of surgery 1
• Reserved for surgery with high risk of acute/chronic pain or opioid-tolerant patients 1

Lidocaine Infusion

• Bolus: 1-2 mg/kg IV followed by 1-2 mg/kg/hour continuous infusion 1
• For major abdominal, pelvic, or spinal surgeries without regional analgesia 1

Contrast Media Premedication

For patients with prior anaphylactoid reaction to radiocontrast media, administer prednisone 50 mg orally at 13,7, and 1 hour before the procedure, plus diphenhydramine 50 mg orally or IM 1 hour before. 1

Standard Prophylaxis Protocol

• Prednisone 50 mg PO at 13 hours, 7 hours, and 1 hour before contrast 1
• Diphenhydramine 50 mg PO or IM 1 hour before 1
• Ephedrine 25 mg PO 1 hour before (optional, often excluded in modern protocols) 1

Emergency Protocol (When Immediate Imaging Required)

• Hydrocortisone 200 mg IV immediately and every 4 hours until contrast administered 1
• Diphenhydramine 50 mg IM 1 hour before contrast 1

Important Considerations

Route Conversion

• Virtually all oral antiemetic medications can be given intravenously at similar doses if the patient cannot take oral medication 1
• IV administration may be preferred for patients with nausea or vomiting at baseline 1

Timing Principles

• Most premedications should be given 30 minutes to 1 hour before the procedure to allow adequate absorption 1
• Corticosteroids for infusion reactions require 1-2 hours for optimal effect 1
• Emergency protocols with IV corticosteroids require immediate administration 1

Common Pitfalls

• Avoid first-generation antihistamines (diphenhydramine) for infusion reactions when possible, as they can exacerbate hypotension and mask symptoms 1
• Do not combine NSAIDs with curative doses of anticoagulants due to 2.5-fold increased bleeding risk 1
• Beta-blocker use increases risk and severity of anaphylactoid reactions, requiring more intensive treatment 1
• Premedication for IV iron is controversial and should be limited to high-risk patients (multiple drug allergies, prior reactions, asthma) 1