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Any correspondence regarding this publication should be sent to the publisher, American Society of Health-System Pharmacists, 4500 East-West Highway, Bethesda, MD, 20814, attention: Special Publishing.

The information presented herein reflects the opinions of the contributors and advisors. It should not be interpreted as an official policy of ASHP or as an endorsement of any product.

Because of ongoing research and improvements in technology, the information and its applications contained in this text are constantly evolving and are subject to the profes-sional judgment and interpretation of the practitioner due to the uniqueness of a clinical situation. The author and editors and ASHP have made reasonable efforts to ensure the accuracy and appropriateness of the information presented in this document. However, any user of this information is advised that the editors and ASHP are not responsible for the continued currency of the information, for any errors or omissions, and/or for any consequences arising from the use of the information in the document in any and all prac-tice settings. Any reader of this document is cautioned that ASHP makes no representa-tion, guarantee, or warranty, express or implied, as to the accuracy and appropriateness of the information contained in this document and specifically disclaims any liability to any party for the accuracy and/or completeness of the material or for any damages arising out of the use or non-use of any of the information contained in this document.

Vice President, Publishing: Daniel J. Cobaugh, PharmD, DABAT, FAACTEditorial Project Manager, Special Publishing: Ruth Bloom, BAProduction Manager: Johnna Hershey, BACover & Page Design: David Wade, BA

Library of Congress Cataloging-in-Publication Data

Names: McPherson, Mary Lynn, author. | American Society of Health-System Pharmacists, issuing body.

Title: Demystifying opioid conversion calculations : a guide for effective dosing / Mary Lynn McPherson.

Description: Second edition. | Bethesda, MD : American Society of Health-System Pharmacists, [2019] | Includes bibliographical references and index.

Identifiers: LCCN 2018023233 | ISBN 9781585284290 (pbk.)Subjects: | MESH: Analgesics, Opioid—administration & dosage | Analgesics,

Opioid—therapeutic use | Drug Dosage CalculationsClassification: LCC RM328 | NLM QV 89 | DDC 615.7/822—dc23LC record available at https://lccn.loc.gov/2018023233

© 2018, American Society of Health-System Pharmacists, Inc. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without written permission from the American Society of Health-System Pharmacists.

ASHP is a service mark of the American Society of Health-System Pharmacists, Inc.; registered in the U.S. Patent and Trademark Office.

Printed in Canada.

ISBN: 978-1-58528-429-0

10 9 8 7 6 5 4 3 2 1


Dedication

This book is dedicated to

My husband, Jim, for his ceaseless love and support;

and

Our daughter, Alexandra, a brilliant palliative care pharmacist,

who makes us proud every single day.


D E M Y S T I F Y I N G O P I O I D C O N V E R S I O N C A L C U L AT I O N S | v

Contents

Foreword ........................................................................................vii

Preface ............................................................................................ix

Reviewers .......................................................................................xi

Acknowledgments ........................................................................xiii

Chapter 1 ..........................................................................................1Introduction to Opioid Conversion Calculations

Chapter 2 ........................................................................................21Converting Among Routes and Formulations of the Same Opioid

Chapter 3 ........................................................................................55Converting Among Routes and Formulations of Different

Opioids

Chapter 4 ........................................................................................81Titrating Opioid Regimens: Around the Clock and to the Rescue!

Chapter 5 ......................................................................................117Transdermal and Parenteral Fentanyl Dosage Calculations

and Conversions

Chapter 6 ......................................................................................147Methadone: A Complex and Challenging Analgesic,

But It’s Worth It!

Chapter 7 ......................................................................................195Patient-Controlled Analgesia and Neuraxial Opioid Therapy

Chapter 8 ......................................................................................223Calculating Doses from Oral Solutions and Suspensions

Chapter 9 ......................................................................................239Lagniappe: A Little Something Extra in Conversion Calculations

Glossary .......................................................................................263

Index .............................................................................................265


D E M Y S T I F Y I N G O P I O I D C O N V E R S I O N C A L C U L AT I O N S | vii

Foreword

Mathematics and biologic systems can be at times incompatible or at least conflic-tual. Mathematics deals with the logical, the predictable, and the precise, while biologic systems are intrinsically changing, often unpredictable and imprecise. To bring it home, a single answer for equianalgesia between two drugs given to different individuals will be imprecise. Should one, therefore, consider a range of equianal-gesia with confidence intervals considering the population and its biologic heteroge-neity or be precise using a single number to express equivalents but with footnotes for population considerations and the multitude of clinical contexts? Dr. McPherson has tirelessly and meticulously worked, putting in long hours with blood, sweat, and tears, to give us an evidence-based table that provides opioid equivalents in an easily understood format but with all the considerations of population and clinical differ-ences (see Table 1-1 and the inside cover). I believe this table is the most useful equianalgesic table published. As an aside, the table should not be mistaken for a “conversion” table because such a table does not exist. Dr. McPherson asks you to put away your “conversion calculators” and use your cognitive abilities and clinical skills to make the right opioid choice for the right patient at the right dose at the right time.

This text, in its second edition, addresses questions of route conversions, dosing strategies, and opioid switches in its opening chapters. The section on dosing strate-gies is clinically quite useful. The middle chapters contain an in-depth discussion on fentanyl, methadone, and patient-controlled analgesia. The patient-controlled analgesia chapter is rather pragmatic because the literature is a bit “messy” as most studies on the subject contain low-grade evidence from case series. The chapter on methadone provides up-to-date dosing schedules that are safe and a plethora of impor-tant considerations when using methadone to avoid the unique problems and pitfalls associated with methadone. Dr. McPherson has included information on buprenor-phine and nalbuphine, which are presently being substituted for the usual potent opioids because of national shortages of parenteral morphine, hydromorphone, and fentanyl. Nalbuphine and buprenorphine have unique properties and should be considered as first-line opioids for certain patients and clinical circumstances.

So why buy this volume if you have the 2009 edition? Well, practice has changed; important data have been published in the basic sciences that have bearing on opioid choices and dosing. We have become more knowledgeable clinically in part due to mistakes that have generated an opioid epidemic. Importantly, opioids have received national attention from the growing number of opioid-related deaths, not all of which are related to heroin; some of the deaths are related to a lack of understanding about opioid pharmacology, equivalents, and poor opioid prescribing habits due to misinfor-mation. Therefore, the information in this book is critical for anyone who wants to practice opioid therapy safely.


viii | D E M Y S T I F Y I N G O P I O I D C O N V E R S I O N C A L C U L AT I O N S

The book is full of humor and common sense. As usual, Dr. McPherson makes it fun and enjoyable to learn. The case presentations give body to theory and will help clini-cians solve difficult pain problems through evidence-based opioid dosing strategies and choices. Lynn provides pearls of wisdom, so if you don’t buy this text, it will be a great loss to yourself and to the patients whom you serve.

Mellar P. Davis, MD, FCCP, FAAHPM

Director of Palliative Services

Geisinger Medical System

Danville, PA


D E M Y S T I F Y I N G O P I O I D C O N V E R S I O N C A L C U L AT I O N S | ix

Preface

I started the preface to the first edition of this book by saying that writing a book such as this one is like purposely walking around with a bull’s eye painted on your forehead. I speculated that if you ask five opioid conversion “experts” about a specific calcula-tion, you’d probably get 15 different answers! I admitted freely that the equianalgesic table was constructed using a few facts, many more semisolid facts, and a significant amount of “this is how we’ve always done it!” In writing the second edition, I struggled with the equianalgesic table just as mightily as I did with the first edition. However, this time around, there were better data to guide me. Thanks to the work of clinical researchers, we now have better equianalgesic data to make well-informed decisions in patient care that allow us to achieve pain relief quickly and safely, while minimizing adverse effects.

Note: The equivalencies and notes in the equianalgesic table (Table 1-1 and the inside cover) in this edition are a little different from the first edition, those charts widely used in practice today, and the equivalencies that drives conversion calculator apps. This may cause a bit of a stir, but as Laurel Thatcher Ulrich said, “Well-behaved women seldom make history.” I’m not trying to be a trouble-maker, rather to provide guidance for best practices in opioid conversion calculations!

What else has informed the development of this second edition? World events to be sure. Everyone reading this knows that we are struggling with two competing public health crises—poorly managed pain (acute and chronic) and an opioid crisis. So, what do opioid conversion calculations have to do with these prob-lems? Everything. Indisputably, pain management has, and will continue to, require the use of opioids in some capacity. Unfortunately, it seems that the pendulum has swung to the far left, and prescribers are increasingly loathe to use opioids. In many cases, this may be appropriate; but in other cases, the underprescribing and under-dosing of opioids may cause needless suffering. Opioid dosing, like dosing most medications, is not “one size fits all.” For example, sending a postoperative patient home on day 2 with 10 Percocet is not always the answer; it may increase suffering and actually increase the risk for the development of chronic pain. This text will help learners how to transition a patient appropriately from one opioid to a different opioid, convert between routes of administration, and safely titrate opioid doses up and down.

What else can I tell you about the second edition? It’s chock FULL of goodies! This book holds great appeal for acute care practitioners, those caring for chronic noncancer pain patients, and clinicians working with patients at the end of life. It’s written in a conversational tone (like we were besties having lunch) while including the latest evidence possible. Contemporary issues such as explaining WHY you cannot increase a continuous infusion opioid before 8 to 12 hours are addressed.


x | D E M Y S T I F Y I N G O P I O I D C O N V E R S I O N C A L C U L AT I O N S

The book contains several new and updated features!

• “Could I Get That to Go, Please?” at the end, highlighting the most important summary points of the chapter.

• Where applicable, chapters contain breakout boxes titled, “Can We Be Steadies?” discussing recent research that reflects steady-state opioid conversion calculations.

• The ever-popular pearls, pitfalls, and fast facts from the first edition remain, updated and added to as appropriate.

• A new chapter, “Lagniappe: A Little Something Extra in Conversion Calcula-tions,” has been added, featuring a discussion of less commonly used opioids (the fentanyls, levorphanol, and nalbuphine) and a baker’s dozen of opioid conversion MIScalulations! These cases will be of great use to staff development professionals and teachers in all practice settings.

Feel free to use the practice cases throughout all the chapters, especially in Chapter 9, as teaching tools.

Last, I would like to share any success this book has achieved or will achieve with the clinicians I have worked with over the years, in doing a million or so opioid conver-sion calculations, particularly professionals in training who struggle so earnestly to master this skill. Most especially, I am humbled by the patients who have allowed me to share in their final journey, which may have included the need for an opioid conversion calculation.

If you would like to email me any thoughts, corrections, or suggestions please feel free to do so at [email protected].

Mary Lynn McPherson

August 2018


D E M Y S T I F Y I N G O P I O I D C O N V E R S I O N C A L C U L AT I O N S | xi

Nancy A. Alvarez, PharmD, BCPS, FAPhA

Assistant Dean, Experiential Education and Continuing Professional Development

Assistant Professor of Pharmacy Practice

Chapman University School of Pharmacy

Irvine, California

Rabia S. Atayee, PharmD, BCPS

Associate Dean for Admissions and Outreach

Associate Professor of Clinical Pharmacy

Palliative Care Pharmacist Specialist

University of California San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences

University of California San Diego Health

San Diego, California

Ryan C. Costantino, PharmD, BCPS

Pharmacy OfficerUnited States ArmyBaltimore, Maryland

Mellar P. Davis, MD, FCCP, FAAHPM

Director of Palliative ServicesGeisinger Medical SystemDanville, Pennsylvania

Leslie Dixon, PharmDPharmacy Clinical ManagerBaton Rouge GeneralBaton Rouge, Louisiana

Maria Foy, PharmD, BCPS, CPE

Pharmacy Care Coordinator, Palliative Care

Abington Hospital-Jefferson Health

Abington, Pennsylvania

Chris Herndon, PharmD, CPE, FASHP

ProfessorDepartment of Pharmacy

PracticeEdwardsville School of

PharmacySouthern Illinois UniversityEdwardsville, Illinois

Holly M. Holmes, MD, MS, AGSF

Associate Professor and Division Director

McGovern Medical SchoolThe University of Texas Health

Science Center at HoustonDivision of Geriatric and

Palliative MedicineHouston, Texas

Karen Snow Kaiser, PhD, RN

Formerly, Clinical Practice Coordinator

Clinical Quality and SafetyUniversity of Maryland Medical

CenterBaltimore, Maryland

Leonette O. Kemp, PharmD, CPE

Clinical Pharmacy Specialist, Oncology and Palliative Care

Methodist University HospitalMemphis, Tennessee

Robin Moorman Li, PharmD, BCACP, CPE

Clinical Associate ProfessorAssistant Director, Jacksonville

CampusUniversity of Florida College of

PharmacyJacksonville, Florida

Kasey L. Malotte, PharmD, BCPS

Advanced Practice PharmacistSupportive Care MedicineCedars-Sinai Medical CenterLos Angeles, California

Ronald Manning, MD, HMDC

Assistant Medical DirectorUnity HospiceGreen Bay, Wisconsin

Eric Prommer, MD, FAAHP, HMDC

Director UCLA/VA Hospice and Palliative Medicine Fellowship Training Program

Director Inpatient Hospice Unit/Greater Los Angeles Healthcare

Associate Professor of Medicine

UCLA School MedicineLos Angeles, California

Laura Scarpaci, PharmD, BCPS

Palliative Care ConsultantHaddonfield, New Jersey

Richard Wheeler, PharmD, BCPS

Pharmacy Clinical ManagerClinical Pharmacy SpecialistPain ManagementMercy HospitalOklahoma City, Oklahoma

Suzanne Wortman, BS, PharmD, BCPS

Clinical Pharmacy SpecialistPenn Highlands DuBoisJohnstown, Pennsylvania

Reviewers


D E M Y S T I F Y I N G O P I O I D C O N V E R S I O N C A L C U L AT I O N S | xiii

Acknowledgments

Writing a book of this nature is a daunting prospect.

• Thanks to the administration and staff at the University of Maryland School of Pharmacy for encouraging me to indulge in this adventure.

• Thanks also to Ruth Bloom at ASHP, a most agreeable editor!

• I am exceedingly grateful to the exhaustive efforts of the reviewers—individuals spent hours and hours combing over every chapter and providing thoughtful feed-back. Each reviewer provided a different perspective, and the book is immeasurably stronger thanks to their careful consideration.

• Thank you to the “fact checkers” who slaved over checking my math so I can stay out of jail!

• I must call out one reviewer in particular—Dr. Mellar P. Davis—seriously the smartest person I know. He reviewed every chapter and gave me detailed feedback (tough love is indeed a beautiful thing). Dr. Davis demanded the very best work I could possibly produce, and the book is so much stronger for it. He also wrote the lovely foreword to this edition!

• Thanks to my family and friends, who remain convinced that I am not in full posses-sion of my faculties for writing another book.

• Thanks to colleagues who have given me solicited and unsolicited feedback since the first edition was published, which I faithfully saved and used in crafting the second edition.


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