NOREPINEPHRINE BITARTRATE IN 5% DEXTROSE
Clinical safety rating: safe
MAOIs can cause severe hypertension Extravasation can cause tissue necrosis and sloughing.
Norepinephrine is a direct-acting sympathomimetic amine that stimulates α1-adrenergic receptors in vascular smooth muscle, causing vasoconstriction and increased blood pressure. It also has β1-adrenergic receptor activity, producing positive inotropic and chronotropic effects on the heart.
| Metabolism | Primarily metabolized by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO) in the liver and other tissues. Major metabolites include normetanephrine and vanillylmandelic acid (VMA). |
| Excretion | Primarily renal: ~80-90% as sulfate and glucuronide conjugates; minor biliary/fecal (<10%). |
| Half-life | Terminal elimination half-life ~2-3 minutes. Clinically, pressor effects wear off rapidly upon infusion cessation. |
| Protein binding | ~25% bound to albumin. |
| Volume of Distribution | 0.08-0.33 L/kg (small, confined to extracellular fluid). |
| Bioavailability | Intravenous: 100%; oral: negligible (<1%) due to extensive first-pass metabolism. |
| Onset of Action | Intravenous: rapid, within 1-2 minutes. |
| Duration of Action | Intravenous: duration of pressor effect is 1-2 minutes after infusion stopped; continuous infusion required to maintain effect. |
IV infusion: initial dose 0.05-0.1 mcg/kg/min titrated to effect, typical range 0.1-0.5 mcg/kg/min, maximum 2 mcg/kg/min.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for renal impairment; monitor for fluid overload from 5% dextrose. |
| Liver impairment | No specific dose adjustment for Child-Pugh class A, B, or C; monitor response due to reduced metabolism. |
| Pediatric use | IV infusion: 0.05-0.1 mcg/kg/min, titrate to desired effect; maximum 2 mcg/kg/min. |
| Geriatric use | Start at lower end of dosing range (0.05-0.1 mcg/kg/min); monitor for arrhythmias and hypertension due to increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
MAOIs can cause severe hypertension Extravasation can cause tissue necrosis and sloughing.
| FDA category | Animal |
| Breastfeeding | Norepinephrine is excreted into breast milk in very small amounts; M/P ratio is not established because endogenous levels are variable. Oral bioavailability is negligible due to rapid gastrointestinal metabolism. However, intravenous administration may produce systemic effects in the mother that could affect the infant. Caution is advised; monitor infant for signs of sympathomimetic effects (tachycardia, hypertension). The American Academy of Pediatrics considers it compatible with breastfeeding. |
■ FDA Black Box Warning
None
| Common Effects | hypotension |
| Serious Effects |
["Hypersensitivity to norepinephrine or any component","Hypovolemia (should be corrected before or concurrently with therapy)","Use with cyclopropane or halothane anesthesia (increases risk of arrhythmias)","Severe peripheral vasoconstriction (e.g., mesenteric or renal) as it may exacerbate ischemia"]
| Precautions | ["Extravasation risk: may cause tissue necrosis if extravasated; administer into a large vein and monitor site","Use with caution in patients with hypertension, hyperthyroidism, arrhythmias, or severe hypoxemia","May cause bradycardia reflexively or with high doses","Monitor blood pressure routinely to avoid hypertension"] |
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| Teratogenic Risk |
| Norepinephrine is a vasopressor that can reduce placental blood flow due to vasoconstriction. In animal studies, high doses caused fetal hypoxia and growth restriction. Human data are limited; however, use in pregnancy is reserved for life-threatening hypotension, with careful monitoring of uterine blood flow. Risk cannot be excluded (FDA Category C). During the first trimester, potential for teratogenicity is unknown but likely low. In the second and third trimesters, risk of fetal hypoxia due to maternal vasoconstriction is increased. Use only if clearly needed. |
| Fetal Monitoring | Continuous maternal blood pressure, heart rate, and ECG monitoring. Assess uterine activity and fetal heart rate (if viable) to detect fetal distress. Monitor for signs of extravasation (tissue ischemia) and fluid overload due to concurrent dextrose administration. In pregnancy, monitor for hypertension, bradycardia, and cardiac arrhythmias. Adjust rate to maintain maternal blood pressure without compromising placental perfusion. |
| Fertility Effects | No specific human studies on fertility effects. In animal studies, no adverse effects on mating or fertility were observed at clinically relevant doses. Norepinephrine is a naturally occurring neurotransmitter; exogenous administration at therapeutic doses is unlikely to impair fertility. However, severe maternal hypotension or stress may transiently affect ovulation or implantation. |