Opioid Risk and Dosing

When assessing Mr. Gateway's pain, you should also address any opioid risk factors he has. It's helpful to also distinguish between the following terms:

• Tolerance - A state of adaptation in which exposure to a drug induces changes that result in a diminution of one or more opioid effects over time.

• Physical dependence - A state of adaptation manifested by a drug class-specific withdrawal syndrome that can be produced by: abrupt cessation, rapid dose reduction, decreaing blood level of the drug, and/or administration of an antagonist.
• Addiction - A primary, chronic, neurobiologic disease with genetic, psychosocial, and environmental factors. It's characterized by behaviors that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, and/or craving.
• Pseudoaddiciton - This is a "concept" and not a true diagnosis and is based off of case reports and small case studies. It can be understood as an iatrogenic syndrome resulting from misinterpretation of relief-seeking behaviors as though they are drug-seeking behaviors that are commonly seen with addiction. The relief-seeking behaviors resolve upon institution of effective analgesic therapy.
• Aberrant behavior - Any medication behaviors departing from prescribed plan of care, ranging from mildly problematic, such as hoarding medications to use for times of severe pain, to selling medications.
• Medication misuse - Use of a medication (with therapeutic intent) other than as directed or as indicated, whether willful or unintentional, and whether harm results or not.

Distinguishing between "addiction" and "pseudoaddiction" can be challenging and often cannot be reconciled.

Equianalgesic Example

From this table, you can compare potencies or "strengths" between the different opioids.

For instance, oral hydromorphone is more potent than oral oxycodone, which is more potent than oral morphine. Thus, lower doses of hydromorphone are needed for a similar effect of a higher dose of oxycodone.

Equianalgesic Fentanyl

Calculations for transdermal fentanyl should be made based on the manufacturer's recommendations using the table below.

Equianalgesic Methadone

There are numerous calculation methods for conversion to methadone. One method commonly used in practice is listed below.