Henke’s Med-Math: Dosage Calculation, Preparation, & Administration 9th Edition

Book Preface

Sitting in a classroom, attending a sluggish orientation session, I was multitasking and working on revisions for this ninth edition of this book. My buddy Mike (a former student and now an excellent critical care nurse) was sitting next to me and asked what I was doing. He queried, “Do dosage calculation textbooks change that much from year to year?” Good question. The methods of calculating medication dosages remain the same (no new methods have been created recently), but the field of health care is changing so rapidly that the many diverse topics and areas related to the calculation of medication dosages and included in this textbook need to be kept as up-to-date as possible. This includes medications, dosages, drug use, technology, and resources. Making sure all content is relevant and current and finding new ways to facilitate student learning are the goals, I strived to achieve with this ninth edition.
Key Features of the Text

– Step-by-step approach to solving problems
– Text organization that builds from simpler concepts to more complex concepts

– Demonstration of four methods of calculation and side-by-side solutions

– Joint Commission–approved abbreviations (as of this publication date)
– Test Your Clinical Savvy—“what if” situations that stimulate critical thinking and foster clinical judgment
– Glossary with definitions and common abbreviations
– Putting it Together: Clinical Case Studies—case studies with application of dosage calculations and critical thinking questions (solutions and suggested answers are in Appendix B)
– Self-tests for pre- or posttesting (can also be used as assessment exercises)
Calculations in Action animations (available on ) to show how problems are solved

New to This Edition

• Improved visual presentation of example calculations, using different colors in the text to show the different methods and distinguish them more clearly from each other
• Additional Putting it Together: Clinical Case Studies and Test Your Clinical Savvy features in several chapters
• Updated drug labels, drug names, pictures, and equipment throughout
• Thoroughly revised section on Systems of Administration in Chapter 10
• Suggested websites for more information and suggested apps to use with dosage calculations

Dosage calculation is connected to the topic of safety in the administration of medications. The Quality and Safety Education for Nurses (QSEN) core competency of safety is defined as “minimizes risk of harm to patients and providers through both system effectiveness and individual performance.” Correct calculation of medications helps to meet this competency.