Ephedrine

Uses

Pseudoephedrine is a decongestant of the mucous membranes of the upper respiratory tract, especially the nasal mucosa, sinuses and eustachian tube. It is used for the symptomatic relief of allergic rhinitis (hay fever), vasomotor rhinitis, the common cold, influenza (flu) and ear congestion caused by ear inflammation or infection. Pseudoephedrine can also be used as a bronchodilator.

Pseudoephedrine is a stereoisomer of Ephedrine with similar but less potent pharmacological activity. It has nasal and bronchial decongestant activity.

Ephedrine is also used to associated treatment for these conditions: Allergic Disorder, Bronchial Asthma, Common Cold, Cough, Depression, Fever, General Anesthesia Induced Hypotension, Headache, Joint Pain, Myasthenia Gravis, Narcolepsy, Nasal Congestion, Rhinorrhoea, Sore Throat, Dry cough

How Ephedrine works

Ephedrine is a direct and indirect sympathomimetic amine. Ephedrine activates adrenergic α and β-receptors as well as inhibiting norepinephrine reuptake, and increasing the release of norepinephrine from vesicles in nerve cells. These actions combined lead to larger quantities of norepinephrine present in the synapse, for longer periods of time, increasing stimulation of the sympathetic nervous system. Ephedrine's stimulation of α-1 receptors causes constriction of veins and a rise in blood pressure, stimulation of β-1 adrenergic receptors increase cardiac chronotropy and inotropy, stimulation of β-2 adrenergic receptors causes bronchodilation.

Dosage

Ephedrine dosage

As a decongestant and symptomatic treatment for upper respiratory tract infections the recommended dose is:

Adults: 1 tablet every 4 to 6 hours, up to maximum of 240 mg in 24 hours

Children:

• 6-12 years of age: 1/2 tablet every 4 to 6 hours daily
• 2-5 years of age: 1/4 tablet every 4 to 6 hours daily
• Less than 2 years of age: This drug is not advised unless specifically recommended by a physician.

Side Effects

Serious adverse effects associated with the use of Pseudoephedrine are rare. Symptoms of central nervous system excitation may occur, including sleep disturbances and, rarely, hallucinations have been reported. Skin rashes, with or without irritation, have occasionally been reported.

Toxicity

Patients experiencing an overdose of ephedrine will present with rapidly increasing blood pressure. Manage overdose with blood pressure monitoring, and possibly the administration of parenteral antihypertensives. The LD₅₀ in mice after oral administration is 785mg/kg, after intraperitoneal administration if 248mg/kg, and after subcutaneous administration is 425mg/kg.

Precaution

Although Pseudoephedrine has virtually no pressor effects in normotensive patients, it should be used with caution in patients suffering mild to moderate hypertension. As with other sympathomimetic agents, Pseudoephedrine should be used with caution in patients with hypertension, heart disease, diabetes, hyperthyroidism, elevated intraocular pressure and prostatic enlargement. Caution should be exercised when using the product in the presence of severe hepatic impairment or moderate to severe renal impairment.

Food Interaction

Ephedrine Drug Interaction

Moderate: amphetamine / dextroamphetamine, amphetamine / dextroamphetamineMinor: ascorbic acid, ascorbic acidUnknown: aspirin, aspirin, epinephrine, epinephrine, diphenhydramine, diphenhydramine, acetaminophen, acetaminophen, valproic acid, valproic acid, cyanocobalamin, cyanocobalamin, cholecalciferol, cholecalciferol, alprazolam, alprazolam

Ephedrine Disease Interaction

Major: cardiovascular diseaseModerate: BPH, diabetes, BPH, diabetes

Volume of Distribution

Oral ephedrine has an average volume of distribution of 215.6L.

Elimination Route

Oral ephedrine reaches an average C_max of 79.5ng/mL, with a T_max of 1.81h, and a bioavailability of 88%.

Half Life

Oral ephedrine has a plasma elimination half life of approximately 6 hours, but there is a large degree of inter-patient variability.

Clearance

Oral ephedrine has a clearance of 23.3L/h but there is a high degree of inter-patient variability.

Elimination Route

Ephedrine is mainly eliminated in the urine. Approximately 60% is eliminated as the unmetabolized parent compound, 13% as benzoic acid conjugates, and 1% as 1,2-dihydroxypropylbenzene.

Pregnancy & Breastfeeding use

Although Pseudoephedrine has been in widespread use for many years without apparent ill consequence, there are no specific data on its use during pregnancy. Caution should therefore be exercised by balancing the potential benefit of treatment to the mother against any possible hazards to the developing foetus. Pseudoephedrine is excreted in breast milk in small amounts but the effect of this on breast-fed infants is not known.

Contraindication

Pseudoephedrine is contraindicated in-

• Hypersensitivity of individuals to this drug
• Severe hypertension and coronary artery disease
• Concurrent use of Mono Amine Oxidase Inhibitor (MAOI) drugs

Acute Overdose

As with other sympathomimetic agents, symptoms of overdosage include irritability, restlessness, tremor, convulsions, palpitations, hypertension and difficulty in micturition. Necessary measures should be taken to maintain and support respiration and control convulsions. Gastric lavage should be performed if indicated. If desired, the elimination of Pseudoephedrine can be accelerated by acid diuresis or by dialysis.

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