Tables of this general type are also available for NSAIDs, benzodiazepines, narcotic conversion table pdf, stimulants, anticholinergics and others as well. Equianalgesic tables are available in different formats, such as pocket-sized cards for ease of reference. A frequently-seen format has the drug names in the left column, the route of administration in the center columns and any notes in the right column.
There are several reasons for switching a patient to a different pain medication. These include practical considerations such as lower cost or unavailability of a drug at the patient’s preferred pharmacy, or medical reasons such as lack of effectiveness of the current drug or to minimize adverse effects.
Equianalgesic charts are also used when calculating an equivalent dosage of the same drug, but with a different route of administration. An equianalgesic chart can be a useful tool, but the user must take care to correct for all relevant variables such as route of administration, cross tolerance, half-life and the bioavailability of a drug.
8 times stronger than morphine, but also has a much longer half-life. Simply switching the patient from 40 mg of morphine to 10 mg of levorphanol would be dangerous due to dose accumulation, and hence frequency of administration should also be taken into account. There are other concerns about equianalgesic charts.
Many charts derive their data from studies conducted on opioid-naïve patients. Repeated administration of a medication is also different from single dosing, as many drugs have active metabolites that can build up in the body.
Patient variables such as sex, age, and organ function may also influence the effect of the drug on the system. These variables are rarely included in equianalgesic charts. The following table lists opioid and non-opioid analgesic drugs and their relative potencies. Values for the potencies represent opioids taken orally unless another route of administration is provided.
As such, their bioavailabilities differ, and they may be more potent when taken intravenously. Methadone is different from most opioids considering its potency can vary depending on how long it is taken. 3 days, yields a potency about 1.