DR. LEAL - AUTONOMIC DRUGS PART2 Flashcards
activates receptor for adrenaline or epinephrine or norepinephrine
ADRENOCEPTOR AGONIST
mimics the sympathetic nervous system
SYMPATHOMIMETIC DRUGS
− Directly interact with and activate adrenoceptors.
− eg, NOREPINEPHRINE and EPINEPHRINE
DIRECT AGONISTS
− Actions are dependent on their ability to enhance the actions of endogenous (naturally occurring in the body) catecholamines (norepinephrine, epinephrine, dopamine)
INDIRECT AGONISTS
Inducing the release of catecholamines by displacing them from adrenergic nerve endings (mechanism of action of ______)
TYRAMINE
not physiologically important in humans but if under the treatment of monoamine oxidase inhibitors, THIS can accumulate. If medicating with MAO inhibitors, avoid cheese or protein-rich foods.
TYRAMINE
Decreasing the clearance of catecholamines by inhibiting their neuronal reuptake (mechanism of action of ____ & _____)
COCAINE
TCA
Receptors for acetylcholine
NICOTINIC
MUSCARINIC
Pharmacologic effects of INDIRECT SYMPATHOMIMETICS are greater under conditions of:
a. Increased sympathetic activity.
b. Norepinephrine storage and release.
Receptors for noradrenergic
ALPHA
BETA
sublingually administered for emergency treatment of hypertensive urgency. If BP is 180/100, it is used to acutely decrease the BP of the patient.
CLONIDINE (CATAPRES)
used if BP is decreased
PHENYLEPHRINE
has atropine, it can increase the heart rate so avoid giving it to patients with arrhythmia.
LOMOTIL
greater affinity in α1 > α2
PHENYLEPHRINE
greater affinity in α2 > α1
CLONIDINE
have the same affinity to both α1 and α2
NE
EPINEP
mostly found in blood vessels = contraction = increase BP
α1 (ALPHA1)
NE or Epi (will attach to β1 in the heart) is used in CPR to increase the force or contraction of the heart
β1 (BETA 1)
given to asthmatic patients to relieve bronchial smooth muscles but still has a side effect to increase the heart rate of patients.
ISOPROTERENOL
Used in CPR to increase contractility of the heart, and increase heart rate, stroke volume, cardiac output, and blood pressure of the patient.
EPINEPHRINE
GIVEN to patients with decreased blood pressure and increased heart rate to increase BP without increasing the heart rate.
PHENYLEPHRINE
• Agonist at both α and β receptors
• Very potent vasoconstrictor and cardiac stimulant
EPINEPHRINE (ADRENALINE)
The rise in systolic blood pressure that occurs after
epinephrine release or administration is caused by its
positive inotropic and chronotropic actions on the heart (predominantly β 1receptors) and the vasoconstriction induced in many vascular beds (α receptors).
epinephrine functions largely as a _____; it is released from the adrenal medulla and carried in the blood to distant sites of action.
HORMONE
• Agonist at both α1 and α2 receptors
• Also activates β1 receptors with similar potency as
epinephrine, but has relatively little effect on β2 receptors.
• Increases peripheral resistance and both diastolic and
systolic blood pressure.
NOREPINEPHRINE (LEVARTERENOL, NORADRENALINE)
• Immediate precursor in the synthesis of norepinephrine.
DOPAMINE
Rate-limiting step in the formation of NE
CONVERSION OF TYROSINE TO DOPAMINE
Endogenous dopamine may have more important effects in
regulating sodium excretion and renal function.
Deficiency in the basal ganglia leads to Parkinson’s disease, which is treated with its precursor Levodopa.
DOPAMINE
• A prodrug that is enzymatically hydrolyzed to desglymidodrine, a selective α1-receptor agonist (peak concentration of desglymidodrine is achieved about 1 hour after midodrine is administered orally)
MIDODRINE
Treatment of orthostatic hypotension, typically due to impaired autonomic nervous system function.
• Increases upright blood pressure and improves orthostatic tolerance, but it may cause hypertension when the subject is supine
MIDODRINE
Decrease blood pressure through actions in the CNS that
reduce sympathetic tone (“sympatholytics”) even though direct application to a blood vessel may cause
vasoconstriction.
ALPHA 2-SELECTIVE AGONISTS
are useful in the treatment of hypertension.
SE (side effects): Sedation
CLONIDINE
METHYLDOPA (for pregnant with high BP)
GUANFACINE
GUANABENZ
for sedation in an intensive care setting or before anesthesia. Can be given to patients who will undergo MRI or CT scan.
DEXMEDETOMIDINE
used as a centrally-acting muscle relaxant.
TIZANIDINE
• Topical decongestant - ability to promote constriction of
the vessels in the nasal mucosa and conjunctiva.
• Large doses may cause hypotension, presumably because of a central clonidine-like effect. Should not be given to
already hypotensive patients.
OXYMETAZOLINE
- Has positive chronotropic and inotropic actions.
- Because IT activates β receptors almost
exclusively, it is a potent vasodilator.
ISOPROTERENOL (ISOPRENALINE)
• Positive inotropic action caused by the isomer with
predominantly β-receptor activity
DOBUTAMINE
• Component of many decongestant mixtures.
• Precursor in the illicit manufacture of methamphetamine. • Given to ongoing operation to increase BP especially if
becoming hypotensive due to blood loss.
EPHEDRINE & PSEUDOEPHEDRINE
TRUTH SERUM
KETAMINE
• Racemic mixture of phenylisopropylamine.
• Use and misuse as a CNS stimulant.
AMPHETAMINE
• Pharmacokinetically similar to EPHEDRINE; however, enters the CNS even more readily, where it has marked stimulant effects on mood and alertness and a depressant effect on appetite
• Actions are mediated through the release of NOREPINEPHRINE and, to some extent, dopamine.
AMPHETAMINE
• Very similar to amphetamine, with an even higher ratio of central to peripheral actions.
METHAMPHETAMINE (N-methylamphetamine)
• An amphetamine variant
• Major pharmacologic effects and abuse potential are
similar to those of amphetamine
METHYLPHENIDATE
used to increase BP.
Methamphetamine
Methylphenidate
Shabu users: decreased sleep, hyperactive and some had heart failures because of increased heart rate and BP.
METHYLPHENIDATE
• A psychostimulant that differs from amphetamine in
structure, neurochemical profile, and behavioral effects
MODAFINIL