Find information on thousands of medical conditions and prescription drugs.

Norepinephrine

Norepinephrine (INN) or noradrenaline (BAN) is a catecholamine and a phenethylamine with chemical formula C8H11NO3. It is released from the adrenal glands as a hormone into the blood, but it is also a neurotransmitter in the nervous system where it is released from noradrenergic neurons during synaptic transmission. As a stress hormone, it affects parts of the human brain where attention and impulsivity are controlled. more...

Home
Diseases
Medicines
A
B
C
D
E
F
G
H
I
J
K
L
M
N
Nabilone
Nadolol
Nafarelin
Nafcillin
Nalbuphine
Nalidixic acid
Nallpen
Naloxone
Naltrexone
Nandrolone
Naphazoline
Naprelan
Naprosyn
Naproxen
Naratriptan
Narcan
Nardil
Naropin
Nasacort
Nasalcrom
Nascobal
Natamycin
Navane
Navelbine
Nebcin
Nebracetam
Nefazodone
Nefiracetam
Nelfinavir
Nembutal
Neoarsphenamine
Neomycin
Neoral
Neosporin
Neulasta
Neupogen
Neurontin
Nevirapine
Nexium
Nialamide
Niaspan
Niclosamide
Nicoderm
Nicorette
Nicotinamide
Nicotine
Nicotinic acid
Nicotrol
Nifedipine
Nifehexal
Nikethamide
Nilstat
Nilutamide
Nimesulide
Nimodipine
Nimotop
Nitrazepam
Nitrofurantoin
Nix
Nizatidine
Nizoral
Nocodazole
Nolvadex
Nomifensine
Norco
Nordazepam
Nordette
Norepinephrine
Norethin
Norfloxacin
Norgestimate
Norgestrel
Norinyl
Noritate
Normodyne
Norplant
Norpramin
Nortriptyline
Norvasc
Norvir
Noscapine
Novafed
Novobiocin
Novocain
Novrad
Nuprin
Nysert
Nystaform
Nystatin
Nystex
Nystop
O
P
Q
R
S
T
U
V
W
X
Y
Z

Along with epinephrine, this compound effects the fight-or-flight response, activating the sympathetic nervous system to directly increase heart rate, release energy from fat, and increase muscle readiness.

The host of physiological changes activated by a stressful event are unleashed in part by activation of a nucleus in the brain stem called the locus ceruleus. This nucleus is the origin of most norepinephrine pathways in the brain. Neurons using norepinephrine as their neurotransmitter project bilaterally from the locus ceruleus along distinct pathways to the cerebral cortex, limbic system, and the spinal cord, among other projections.

At synapses it acts on both alpha and beta adrenoreceptors.

Antidepressants

Changes in the norepinephrine system are implicated in depression. Serotonin-norepinephrine reuptake inhibitors (SNRIs) treat depression by increasing the amount of serotonin and norepinephrine available to postsynaptic cells in the brain. There is some recent evidence showing that the norepinephrine transporter also normally transports some dopamine as well, implying that SNRIs may also increase dopamine transmission. This is because SNRIs work by preventing the serotonin and norepinephrine transporter from taking their respective neurotransmitters back to their storage vesicles for later use. If the norepinephrine transporter normally recycles some dopamine too, then SNRIs will also enhance dopaminergic transmission. Therefore, the antidepressant effects associated with increasing norepinephrine levels may also be partly or largely due to the concurrent increase in dopamine (particularly in the prefrontal cortex).

Some other antidepressants (for example some tricyclic antidepressants (TCAs)) affect norepinephrine as well, in some cases without affecting other neurotransmitters (at least not directly).

Role in attention

Norepinephrine, along with dopamine, has come to be recognized as playing a large role in attention and focus. In response, Eli Lilly Pharmaceuticals has released Strattera (atomoxetine), a selective norephinephrine reuptake inhibitor, for the treatment of ADHD in adults and children. Strattera is unique in medications specifically indicated for ADHD, as, unlike the psychostimulants (methylphenidate, dextroamphetamine, Adderall (a racemic mixture of amphetamine salts)), it affects norephinephrine, rather than dopamine. As a result, Strattera has a very low abuse potential and can act 24 hours-per-day. (It should be noted that some antidepressants, including SNRIs, have been used off-label for treatment of ADHD.)

Clinical use

Norepinephrine (commonly referred to by the brand name Levophed) is also a powerful medicine used in critically-ill patients as a vasopressor. It is given intravenously and acts on both alpha-1 and beta-1 adrenergic receptors to cause vasoconstriction. Norepinephrine is mainly used to treat patients in septic shock.

Read more at Wikipedia.org


[List your site here Free!]


The safety of dopamine versus norepinephrine as vasopressor therapy in septic shock
From CHEST, 10/1/05 by Jaime J. Simon Grahe

PURPOSE: We evaluated a strategy of dopamine (DA) vs norepinephrine (NE) as the primary vasopressor support in patients with septic shock. Concern for potential adverse events or a significant improvement in outcome prompted an interim safety analysis after approximately 50% of the target subjects were enrolled.

METHODS: MICU patients with septic shock were prospectively randomized to receive either DA or NE as the first-line vasopressor. All patients were treated with early-goal directed medical therapy including luid resuscitation, antibiotics, tight glycemic control and management of adrenal insufficiency, as appropriate. A protocol governed the titration of vasopressors to achieve a mean arterial pressure (MAP) of > 60mmHg or systolic blood pressure (SBP) > 90mmHg. After the maximum dose of either DA or NE was reached, patients received vasopressin at a fixed dose of 0.04 units/minute, followed by titration of phenylephrine to maintain the bloodpressure goal. An interim analysis was performed to evaluate safety and efficacy of each vasopressor.

RESULTS: Sixty-six patients, 35 DA and 31 NE, have been enrolled in the study. APACHE II scores, gender, and age were all similar at baseline between the two groups. There was no significant difference in mortality comparing the two groups (DA 40%, NE 41.8%). Cardiac dysrhythmias occurred in 31.4% of the DA group compared to 3.2% for NE (p=0.003). All cardiac dysrhythmias required an intervention.

CONCLUSION: There was a significant increase in cardiac dysrhythmias associated with DA treatment in comparison to NE treatment of septic shock.

CLINICAL IMPLICATIONS: While there was no significant difference in mortality between the two vasopressor regimens, the significant increase in dysrhythmias associated with DA administration raises significant safety concerns. Further testing is needed to confirm the safety of dopamine and ensure that it is not detrimental to septic shock patients.

DISCLOSURE: Jaime Simon Grahe, None.

Jaime J. Simon Grahe DO * Gourang P. Patel PharmD Ellen Elpern RN Robert A. Balk MD Rush University Medical Center, Chicago, IL

COPYRIGHT 2005 American College of Chest Physicians
COPYRIGHT 2005 Gale Group

Return to Norepinephrine
Home Contact Resources Exchange Links ebay