PHRM 825: Adrenergic Drugs Flashcards
1
Q
Norepinephrine
A
- alpha 1 and beta 1 receptor agonist
- Substrate for MAO and COMT
- Administration: parenteral
- Used as a pressor
- Sodium bisulfate used in preparations to prevent oxidation
2
Q
Epinephrine
A
- Potent alpha, beta 1, and beta 2 receptor agonist
- Substrate for MAO and COMT
- Administration: Parenteral
- Sodium bisulfate used in preparations to prevent oxidation
- Available as many salts: hydrochloride, nitrate, bitartrate
- Uses: Anaphylaxis, glaucoma, in combination with local anesthetics
3
Q
Isoproterenol
A
Beta 1 and beta 2 receptor agonist
4
Q
Phenylephrine
A
- Potent alpha 1 receptor agonist
- Substrate for MAO
- Administration: parenteral, oral, local
- Uses: Mydriasis without cycloplegia, glaucoma, pressor, nasal decongestant
5
Q
Naphazoline
A
- Partial agonists at alpha 1 receptors
- Administrated locally/topically to promote vasoconstriction’
- Basic nature of imidazoline ring causes compounds to exist in ionized form at physiologic pH
- Tachyphylaxis/Desensitization
- Uses: Nasal and ophthalmic decongestants
6
Q
Tetrahydrozoline
A
- Partial agonists at alpha 1 receptors
- Administrated locally/topically to promote vasoconstriction’
- Basic nature of imidazoline ring causes compounds to exist in ionized form at physiologic pH
- Tachyphylaxis/Desensitization
- Uses: Nasal and ophthalmic decongestants
7
Q
Oxymetazoline
A
- Partial agonists at alpha 1 receptors
- Administrated locally/topically to promote vasoconstriction’
- Basic nature of imidazoline ring causes compounds to exist in ionized form at physiologic pH
- Tachyphylaxis/Desensitization
- Uses: Nasal and ophthalmic decongestants
8
Q
Clonidine
A
- Selective alpha 2 receptor agonist
- (Phenylimino)imidazolidine
- The basicity fo the guanidine group is decreased because of the attachment to the dichlorophenyl ring
- Clinical effect linked to activation of alpha 2 receptors in the nucleus of the solitary tract (cardiovascular center)
- Administration: Oral, parenteral, transdermal
- Uses: Hypertension, opiate withdrawal
9
Q
How do alpha 2 adrenergic agonists reduce BP?
A
By reducing sympathetic output from the brain
10
Q
Guanabenz
A
- Half life: ~6 hours
- “Open-ring” imidazolidines
- Two atom bridge to the guanidine group decreases the pKa so that the drug is mostly non-ionized at physiological pH
- Administration: Oral
- Uses: Hypertension
11
Q
Guanfacine
A
- Half life: ~12-16 hours
- “Open-ring” imidazolidines
- Two atom bridge to the guanidine group decreases the pKa so that the drug is mostly non-ionized at physiological pH
- Administration: Oral
- Uses: Hypertension, ADHD
12
Q
Methyldopa
A
- Prodrug metabolized to active alpha 2 receptor agonist, (1R,2S)-alpha-methylnorepinephrine
- Act as CNS alpha 2 receptors to decrease sympathetic outflow
- Water soluble, ester hydrochloride salt Methyldopate is used for parenteral solutions
- Administration: Oral (methyldopa); Parenteral (methyldopate)
- Uses: Hypertension
13
Q
Adverse effects of alpha 2 adrenergic receptor agonists
A
- Sedation
- Sodium and water retention
- Dry mouth
- Withdrawal syndrome
14
Q
Apraclonidine
A
- alpha 2 receptor agonist
- Uses: Glaucoma
15
Q
Tizanidine
A
- alpha 2 receptor agonist
- Uses: Muscle spasticity
16
Q
Isoproterenol
A
- Non-selective beta receptor agonist
- Bronchodilation
- Increased cardiac output
- Metabolized by conjugation reactions (phase II) and by COMT
- Not sensitive to MAO
- Administration: Oral, parenteral, local (inhaled)
- Uses: Asthma, COPD, cardiostimulant
17
Q
Metaproterenol
A
- Selective beta 2 receptor agonist
- Resorcinol derivatives
- Bronchodilation
- Cardiac effects observed only at high doses
- Not metabolized by MAO or COMT
- Longer duration of action than isoproterenol
- Administration: Oral, parenteral, local (inhaled)
- Uses: asthma, COPD
18
Q
Terbutaline
A
- Selective beta 2 receptor agonist
- Resorcinol derivatives
- Bronchodilation
- Cardiac effects observed only at high doses
- Not metabolized by MAO or COMT
- Longer duration of action than isoproterenol
- Administration: Oral, parenteral, local (inhaled)
- Uses: asthma, COPD, tocolytic (prevents premature labor)
19
Q
Albuterol
A
- Selective beta 2 receptor agonist
- Meta hydroxymethyl derivatives
- Bronchodilation
- Cardiac effects observed only at high doses
- Not metabolized by MAO or COMT
- Longer duration of action than isoproterenol
- Administration: Oral, local (inhaled)
- Uses: Asthma, COPD
20
Q
Salmeterol
A
- Selective beta 2 receptor agonist
- Meta hydroxymethyl derivatives
- Bronchodilation
- Onset of action: 10-20 mins
- Cardiac effects observed only at high doses
- Not metabolized by MAO or COMT
- Longer duration of action than isoproterenol
- Administration: Inhaled (metered dose inhaler and powder)
- Uses: Long-term asthma, COPD
- Not recommended for acute treatment of asthma sympmtoms
21
Q
Formoterol
A
- Selective beta 2 receptor agonists
- Bronchodilation
- Not metabolized by MAO or COMT
- Onset of action: <5 mins
- Longer duration of action
- Administration: inhaled (metered dose inhaler and powder)
- Uses: long-term asthma, COPD
- Not recommended for acute treatment of asthma symptoms
22
Q
Dobutamine
A
- Dopamine derivative
- Available as a racemic mixture
- (+)-enantiomer: potent beta 1 receptor agonist; alpha 1 receptor antagonist
- (-)-enantiomer: potent alpha 1 receptor agonist, potency for beta receptors reduced 10X
- Net effect is positive inotropic effect on heart with little chronotropic effect
- Metabolized by COMT and conjugation
- Not sensitive to MAO
- Short half-life (~2 minutes)
- Administration: Parenteral
- Use: Acute heart failure, shock
23
Q
What are examples of indirect-acting sympathomimetics?
A
- Amphetamine
- Pseudoephedrine
- Ephedrine
- Phenylpropanolamine
- Tyramine
24
Q
How do indirect-acting sympathomimetics work?
A
Promote release of NE via reverse action plasma membrnae transporter
25
Q
Clinical uses of indirect-acting sympathomimetics
A
- Amphetamines: ADHD, narcolepsy, anorexiant
- Others: nasal decongestants
