16 Questions
What is the percentage of adrenaline secretions from the adrenal medulla?
80%
What is the effect of adrenaline on the aqueous humor dynamics in the eye?
Decreases aqueous formation
What is the route of administration for bronchial asthma?
Inhalation by nebulizer
What is the percentage of adrenaline excreted unchanged in the urine?
2%
Why is adrenaline not administered orally?
It is not absorbed orally
What is the effect of adrenaline on the cardiovascular system?
It causes vasoconstriction and hypertension
What is the purpose of using adrenaline in Loewi's test?
To test the response of the eye to adrenaline
Why is adrenaline stored in an acidic medium?
It is unstable in alkaline medium
What is the reason behind adrenalines instability in alkaline medium?
It is oxidized to adrenochrome
What is the primary mechanism of adrenaline reuptake?
Reuptake by nerve endings and tissues
What is the effect of adrenaline on ciliary vessels in the eye?
Vasoconstriction
What is the purpose of using adrenaline in cardiac resuscitation?
To improve circulation
Why is adrenaline prepared in dark brown ampoules?
To protect it from light
What is the effect of adrenaline on trabecular outflow in the eye?
Facilitation
What is the reason behind adrenaline's short duration of action when administered I.M.?
Rapid absorption
What is the effect of adrenaline on skin and mucous membranes?
Vasoconstriction
Study Notes
Adrenaline (Epinephrine)
Source and Chemistry
- Found in adrenal medulla (80% of secretions) and some CNS tracts
- Oxidized to toxic adrenochrome when exposed to air and light, so prepared in dark brown ampoules
- Unstable in alkaline medium, stored in acidic medium
Kinetics
- Not absorbed orally
- Routes of administration:
- Subcutaneous (½ ml 1/1000 Solution): vasoconstriction slows absorption, safe and long duration
- Inhalation (1/100 Solution): by nebulizer or atomizer in bronchial asthma
- Eye drops (2% solution): in open angle glaucoma and Loewi's test
- Intra-Cardiac: in cardiac resuscitation, impaired circulation
- IM: rapid absorption and short duration, used in anaphylactic shock
- Distribution: does not pass blood-brain barrier
- Fate:
- Reuptake: 80% by nerve endings and tissues
- Metabolism: 18% by MAO and COMT
- Excretion: 2% unchanged in urine
Dynamics
Mechanism of Action
- Stimulates all adrenergic receptors (α1, α2, β1, β2, and weak β3)
Pharmacological Effects
- Local effects:
- Skin and mucous membrane (α1 receptor): vasoconstriction, decongestion, and haemostasis
- Eye:
- Produces vasoconstriction of conjunctival blood vessels
- No mydriasis due to destruction by alkalinity of tears and vasoconstriction of blood vessels
- Effects on aqueous humor dynamics:
- α1: vasoconstriction of ciliary vessels reduces aqueous formation
- β2: facilitates trabecular outflow, decreasing IOP
Adrenaline (Epinephrine)
Source and Chemistry
- Found in adrenal medulla (80% of secretions) and some CNS tracts
- Oxidized to toxic adrenochrome when exposed to air and light, so prepared in dark brown ampoules
- Unstable in alkaline medium, stored in acidic medium
Kinetics
- Not absorbed orally
- Routes of administration:
- Subcutaneous (½ ml 1/1000 Solution): vasoconstriction slows absorption, safe and long duration
- Inhalation (1/100 Solution): by nebulizer or atomizer in bronchial asthma
- Eye drops (2% solution): in open angle glaucoma and Loewi's test
- Intra-Cardiac: in cardiac resuscitation, impaired circulation
- IM: rapid absorption and short duration, used in anaphylactic shock
- Distribution: does not pass blood-brain barrier
- Fate:
- Reuptake: 80% by nerve endings and tissues
- Metabolism: 18% by MAO and COMT
- Excretion: 2% unchanged in urine
Dynamics
Mechanism of Action
- Stimulates all adrenergic receptors (α1, α2, β1, β2, and weak β3)
Pharmacological Effects
- Local effects:
- Skin and mucous membrane (α1 receptor): vasoconstriction, decongestion, and haemostasis
- Eye:
- Produces vasoconstriction of conjunctival blood vessels
- No mydriasis due to destruction by alkalinity of tears and vasoconstriction of blood vessels
- Effects on aqueous humor dynamics:
- α1: vasoconstriction of ciliary vessels reduces aqueous formation
- β2: facilitates trabecular outflow, decreasing IOP
This quiz covers the source, chemistry, and kinetics of adrenaline (epinephrine), including its presence in the adrenal medulla, chemical properties, and routes of administration. Learn about the absorption, preparation, and storage of adrenaline.
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