Inotrope

Source: Wikipedia, the free encyclopedia.
(Redirected from
Inotropic
)
Not to be confused with
ionotropic
.

An inotrope

muscular contractions. Negatively inotropic agents weaken the force of muscular
contractions. Positively inotropic agents increase the strength of muscular contraction.

The term inotropic state is most commonly used in reference to various

pathological conditions. For example, enlarged heart muscle can increase inotropic state, whereas dead heart muscle
can decrease it.

Medical uses

Both positive and negative inotropes are used in the management of various cardiovascular conditions. The choice of agent depends largely on specific pharmacological effects of individual agents with respect to the condition. One of the most important factors affecting inotropic state is the level of calcium in the cytoplasm of the muscle cell. Positive inotropes usually increase this level, while negative inotropes decrease it. However, not all positive and negative drugs affect calcium release, and, among those that do, the mechanism for manipulating the calcium level can differ from drug to drug.

While it is often recommended that

central line due to the risk of local tissue injury if the medication enters the local tissues, they are likely safe when given for less than two hours through good peripheral intravenous catheterization.[6]

Positive inotropic agents

By increasing the concentration of intracellular calcium or increasing the sensitivity of receptor proteins to calcium, positive inotropic agents can increase myocardial contractility.[7] Concentrations of intracellular calcium can be increased by increasing influx into the cell or stimulating release from the sarcoplasmic reticulum.[8]

Once in the cell, calcium can pass through one of two channels: the L-type calcium channel (long-lasting) and the T-type calcium channel (transient). These channels respond to voltage changes across the membrane differently: L-type channels respond to higher membrane potentials, open more slowly, and remain open longer than T-type channels.

Because of these properties, L-type channels are important in sustaining an action potential, while T-type channels are important in initiating them.[9]

By increasing intracellular calcium, via the action of the L-type channels, the action potential can be sustained for longer and therefore, contractility increases.

Positive inotropes are used to support cardiac function in conditions such as

congestive heart failure, cardiogenic shock, septic shock, myocardial infarction, cardiomyopathy, etc.[10]

Examples of positive inotropic agents include:[citation needed]

Negative inotropic agents

Negative inotropic agents decrease myocardial

congestive heart failure.[13]

Examples of negative inotropic agents include:

Class IA

antiarrhythmics
such as

Class IC antiarrhythmics such as

See also

Notes

  1. ^ The word inotrope is ISV via Neo-Latin, from Greek in-, fibre or sinew, plus -trope, turning or moving. The prevalent pronunciations are /ˈaɪnətroʊp, -noʊt-/[1][2] and /ˈɪn-/,[3][4] with /ˈiːn-/[2][5] being less common.

References

  1. ^ "Inotrope". Merriam-Webster's Collegiate Dictionary. Merriam-Webster.
  2. ^ a b "Inotrope". The American Heritage Dictionary of the English Language. Houghton Mifflin Harcourt.
  3. ^ "Inotrope". Dorland's Illustrated Medical Dictionary. Elsevier.
  4. ^ "Inotrope". Stedman's Medical Dictionary. Wolters Kluwer.
  5. ^ "Inotrope". Merriam-Webster's Medical Dictionary.
  6. PMID 25669592
    .
  7. ^ Gordon S, Saunders A (November 2015). "Positive Inotropes". The Merck Veterinary Manual. Retrieved 2016-11-28.
  8. ^ Berry W, McKenzie C (January 2010). "Use of inotropes in critical care". Clinical Pharmacist. 2: 395. Retrieved 2016-11-28.
  9. ISBN 9780495391845
    .
  10. PMID 24857641
    .
  11. PMID 34916560
    .
  12. S2CID 29440212
    .
  13. PMID 31159740
    .
  14. PMID 23325883
    .
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