EPHEDRINE SULFATE (Page 2 of 3)

7 DRUG INTERACTIONS

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Risk Summary

Limited published data on the use of ephedrine sulfate are insufficient to determine a drug associated risk of major birth defects or miscarriage. However, there are clinical considerations [see Clinical Considerations]. Animal reproduction studies have not been conducted with ephedrine sulfate.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or

other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Clinical Considerations

Fetal/Neonatal adverse reactions

Cases of potential metabolic acidosis in newborns at delivery with maternal ephedrine exposure have been reported in the literature. These reports describe umbilical artery pH of ≤7.2 at the time of delivery [see Clinical Pharmacology 12-12.3]. Monitoring of the newborn for signs and symptoms of metabolic acidosis may be required. Monitoring of infant’s acid-base status is warranted to ensure that an episode of acidosis is acute and reversible.

8.2 Lactation

Risk Summary

Limited published literature reports that ephedrine is present in human milk. However, no information is available on the effects of the drug on the breastfed infant or the effects of the drug on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for ephedrine sulfate injection and any potential adverse effects on the breastfed child from ephedrine sulfate injection or from the underlying maternal condition.

8.4 Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

8.5 Geriatric Use

Clinical studies of ephedrine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.

In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Renal Impairment

Ephedrine and its metabolite are excreted in urine. In patients with renal impairment, excretion of ephedrine is likely to be affected with a corresponding increase in elimination half-life, which will lead to slow elimination of ephedrine and consequently prolonged pharmacological effect and potentially adverse reactions. Monitor patients with renal impairment carefully after the initial bolus dose for adverse events.

10 OVERDOSAGE

Overdose of ephedrine can cause a rapid rise in blood pressure. In the case of an overdose, careful monitoring of blood pressure is recommended. If blood pressure continues to rise to an unacceptable level, parenteral antihypertensive agents can be administered at the discretion of the clinician.

11 DESCRIPTION

Ephedrine sulfate is an alpha- and beta-adrenergic agonist and a norepinephrine-releasing agent. Ephedrine sulfate injection, USP is a clear, colorless, sterile solution for intravenous injection. Each mL contains ephedrine sulfate 50 mg in water for injection as a single-dose product. The pH range is 4.5 to 7.0. The drug product must be diluted before intravenous administration. The chemical name of ephedrine sulfate is (1R,2S)-(-)-2-methylamine-1-phenylpropan-1-ol sulfate (2:1) (salt). Its molecular weight is 428.54.

The structural formula is:

Image 1

Ephedrine sulfate darkens on exposure to light. It is freely soluble in water and ethanol, very slightly soluble in chloroform, and practically insoluble in ether.

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Ephedrine sulfate is a sympathomimetic amine that directly acts as an agonist at α- and ß­ adrenergic receptors and indirectly causes the release of norepinephrine from sympathetic neurons. Pressor effects by direct alpha- and beta-adrenergic receptor activation are mediated by increases in arterial pressures, cardiac output, and peripheral resistance. Indirect adrenergic stimulation is caused by norepinephrine release from sympathetic nerves.

12.2 Pharmacodynamics

Ephedrine stimulates heart rate and cardiac output and variably increases peripheral resistance; as a result, ephedrine usually increases blood pressure. Stimulation of the α-adrenergic receptors of smooth muscle cells in the bladder base may increase the resistance to the outflow of urine. Activation of ß-adrenergic receptors in the lungs promotes bronchodilation.

The overall cardiovascular effect from ephedrine is the result of a balance among α-1 adrenoceptor-mediated vasoconstriction, ß-2 adrenoceptor-mediated vasoconstriction, and ß-2 adrenoceptor-mediated vasodilatation. Stimulation of the ß-1 adrenoceptors results in positive inotrope and chronotrope action.

Tachyphylaxis to the pressor effects of ephedrine may occur with repeated administration [see Warnings and Precautions 5-5.3].

12.3 Pharmacokinetics

Publications studying pharmacokinetics of oral administration of (-)-ephedrine support that (-)­-ephedrine is metabolized into norephedrine. However, the metabolism pathway is unknown. Both the parent drug and the metabolite are excreted in urine. Limited data after IV administration of ephedrine support similar observations of urinary excretion of drug and metabolite. The plasma elimination half-life of ephedrine following oral administration was about 6 hours.

Ephedrine crosses the placental barrier [see Use in Specific Populations 8-8.1].

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis and Mutagenesis and Impairment of Fertility

Carcinogenesis: Two-year feeding studies in rats and mice conducted under the National Toxicology Program (NTP) demonstrated no evidence of carcinogenic potential with ephedrine sulfate at doses up to 10 mg/kg/day and 27 mg/kg/day (approximately 2 times and 3 times the maximum human recommended dose on a mg/m2 basis, respectively).

Mutagenesis: Ephedrine sulfate tested negative in the in vitro bacterial reverse mutation assay, the in vitro mouse lymphoma assay, the in vitro sister chromatid exchange, and the in vitro chromosomal aberration assay.

Impairment of Fertility: Studies to evaluate the effect of ephedrine on fertility have not been conducted.

14 CLINICAL STUDIES

The evidence for the efficacy of ephedrine injection is derived from the published literature. Increases in blood pressure following administration of ephedrine were observed in 14 studies, including 9 where ephedrine was used in pregnant women undergoing neuraxial anesthesia during Cesarean delivery, 1 study in non-obstetric surgery under neuraxial anesthesia, and 4 studies in patients undergoing surgery under general anesthesia. Ephedrine has been shown to raise systolic and mean blood pressure when administered as a bolus dose following the development of hypotension during anesthesia.

16 HOW SUPPLIED

EPHEDRINE SULFATE INJECTIONS, USP is supplied in the following dosage forms.
NDC 51662-1325-1
EPHEDRINE SULFATE INJECTIONS, USP 50 mg/mL 1mL VIAL

HF Acquisition Co LLC, DBA HealthFirst Mukilteo, WA 98275

Also supplied in the following manufacture supplied dosage forms

Ephedrine Sulfate Injection, USP, 50 mg/mL, is supplied as follows:

Vial stoppers are not manufactured with natural rubber latex.

Store ephedrine sulfate injection, 50 mg/mL, at 20° to 25°C (68° to 77°F), with excursions permitted to 15°C to 30°C (59°F to 86°F) [See USP Controlled Room Temperature.] Protect from light. Store in carton until time of use. For single use only. Discard unused portion.