Selective alpha1 agonists (indirect sympathomimetics)

Question 1

Phenylephrine

Answer 1

Alpha1 selective agonist
Local application–> nasal decongestant: vasoconstriction (reduction of muscoal hyperaemia and secretion)
SIDE EFFECTS: paradoxic hyperaemia (rebound congestion), ischaemic damage to muscoa (with prolonged use), sometimes but rarely it has systemic side effects like vasoconstriction and hypertension

Opthamology and surgery use—> pupil dilation for diagnostic or therapeutic purposes

Systemic use–> treatment of colds/flu: phenylephrine is used in combination with NSAIDs or paracetamol
SIDE EFFECTS: vasoconstriction, hypertension

Question 2

Oxymetazolin

Answer 2

Alpha agonist (a2>a1)
Local application–> nasal decongestant: vasoconstriction (reduction of muscoal hyperaemia and secretion)
SIDE EFFECTS: paradoxic hyperaemia (rebound congestion), ischaemic damage to muscoa (with prolonged use), sometimes but rarely it has systemic side effects like vasoconstriction and hypertension

Question 3

Xylometazoline

Answer 3

Alpha agonist
Local application–> nasal decongestant: vasoconstriction (reduction of muscoal hyperaemia and secretion)
SIDE EFFECTS: paradoxic hyperaemia (rebound congestion), ischaemic damage to muscoa (with prolonged use), sometimes but rarely it has systemic side effects like vasoconstriction and hypertension

Question 4

Ephedrine

Answer 4

Indirect sympathomimetic
NE releaser
In the past it was used to enhance muscle strength in myasthenia gravis: either through NE release from sympathetic nerves or with its weak Beta2 agonistic effect

Question 5

Methylphenidate

Answer 5

Indirect sympathomimetic
Commonly used to treat ADHD and in some cases narcolepsy
It functions by increasing the levels of dopamine and NE in the brain helping to improve focus, attention, and impulse control
It blocks the reuptake of dopamine and NE into the presynaptic neurons
SIDE EFFECTS: insomnia, decreased appetite, tachycardia, anxiety or nervousness
There is a potential for misuse and addiction so it is classified as a controlled substance