Mephentermine


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : IV Maintenance of BP in hypotensive states 30-45 mg as single dose, repeated as necessary or followed by IV infusion of 0.1% mephentermine in 5% dextrose, rate and duration of administration will depend on patient's response. Hypotension secondary to spinal anesth in obstetric patients 15 mg as a single dose, repeat if needed.
Dosage Details
Intravenous
Maintenance of blood pressure in hypotensive states
Adult: 30-45 mg as a single dose, repeated as necessary or followed by IV infusion of 0.1% mephentermine in 5% dextrose, rate and duration of administration will depend on patient's response.

Intravenous
Hypotension secondary to spinal anaesthesia in obstetric patients
Adult: 15 mg as a single dose, repeat if needed.
Contraindications
Hypotension caused by phenothiazines. Hypertension. Phaeochromocytoma.
Special Precautions
Patient on MAOIs. For shock due to loss of blood or fluid, give fluid replacement therapy primarily, CVS disease, hypertension, hyperthyroidism, chronic illnesses. Lactation, pregnancy.
Adverse Reactions
Drowsiness, incoherence, hallucinations, convulsions, tachycardia. Fear, anxiety, restlessness, tremor, insomnia, confusion, irritability and psychosis. Nausea, vomiting, reduced appetite, urinary retention, dyspnoea, weakness.
Potentially Fatal: AV block, CNS stimulation. Cerebral haemorrhage and pulmonary oedema, ventricular arrhythmias.
Drug Interactions
Antagonises effect of hypotensive agents. Severe hypertension with MAOIs and possibly TCAs. Additive vasoconstricting effects with ergot alkaloids, oxytocin.
Potentially Fatal: Risk of arrhythmia in patients undergoing anesthesia with cyclopropane and halothane.
Action
Description: Mephentermine appears to act by indirect stimulation of β-adrenergic receptors causing the release of norepinephrine from its storage sites. It has a positive inotropic effect on the myocardium. AV conduction and refractory period of AV node is shortened with an increase in ventricular conduction velocity. It dilates arteries and arterioles in the skeletal muscle and mesenteric vascular beds, leading to an increase in venous return.
Onset: 5-15 minutes (IM), immediate (IV).
Duration: 4 hr (IM), 30 minutes (IV).
Pharmacokinetics:
Metabolism: Rapidly demethylated in the body followed by hydroxylation.
Excretion: Via urine (as unchanged and metabolites); more rapid in acidic urine.
MIMS Class
Disclaimer: This information is independently developed by MIMS based on Mephentermine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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