The main difference between Ephedrine and Pseudoephedrine is that Ephedrine is sympathomimetic alkaloid derived from a plant of Genus ephedra while Pseudoephedrine is the isomer of ephedrine with sympathomimetic activity.
Ephedrine vs. Pseudoephedrine
Ephedrine has direct or indirect sympathomimetic activity on both α, and β receptors, on the other hand, Pseudoephedrine has indirect sympathomimetic activity on α receptors and indirect weak sympathomimetic activity on β receptors. Ephedrine increases the release and activity of norepinephrine on adrenergic receptors, whereas Pseudoephedrine increases the release of the endogenous norepinephrine from the storage vesicles. Ephedrine has a structure similar to the amphetamine and methamphetamines, on the other hand, Pseudoephedrine is phenethylamine. Ephedrine is used in low doses to treat the hypotension while Pseudoephedrine is used in higher doses to treat the hypotension. Ephedrine has strong bronchodilatory effect as compared to Pseudoephedrine, on the other hand, Pseudoephedrine has weak bronchodilatory effect as compared to Ephedrine.
What is Ephedrine
Ephedrine is classified as Sympathomimetic agent which acts as an agonist at α and β receptors. Ephedrine is also considered as the mixed-acting sympathomimetic drug because it increases the release of norepinephrine from the sympathetic neurons. Ephedrine has two asymmetrical carbon atoms. Ephedrine lacks a catechol moiety. Ephedrine is effective when given orally. Ephedrine increases heart rate and cardiac output. Ephedrine increases peripheral resistance but invariably. Usually, Ephedrine increases blood pressure. When Ephedrine stimulates α receptors of smooth muscle cells of the bladder, it increases the resistance to outflow of urine. When ephedrine stimulates β receptors in the lungs, it causes bronchodilation. Ephedrine stimulates CNS and is a potent CNS stimulator. When taken orally, the effects of Ephedrine persist for a long time. Elimination of Ephedrine is through urine, and it eliminates as unchanged drug. The half-life of Ephedrine is 3 to 6 hours. Ephedrine is used in the treatment of asthma, and it is used to treat hypotension caused by spinal anesthesia. Adverse effects of Ephedrine are hypertension, especially when Ephedrine is taken through parenteral route or when it is taken in higher than recommended oral doses. CNS adverse effects include insomnia.
Examples of famous brands containing Ephedrine are Bronkaid, Primatene tablets, etc.
What is Pseudoephedrine?
Pseudoephedrine is classified as Sympathomimetic agent which acts as an agonist at α receptors. Pseudoephedrine is phenethylamine that is an isomer of Ephedrine with the sympathomimetic property. Pseudoephedrine has two asymmetric carbon atoms. Pseudoephedrine displaces norepinephrine from its storage sites and released norepinephrine acts as the alpha agonist. Pseudoephedrine has weak agonist activity at beta-adrenergic receptors. Pseudoephedrine has less central nervous system effects. Receptor stimulation causes vasoconstriction and leads to a decrease in nasal and sinus congestion. Pseudoephedrine is used as a nasal decongestant associated with cold and allergies. Pseudoephedrine is used as a wakefulness-promoting agent. Pseudoephedrine is also had antitussive pharmacological action. Pseudoephedrine is also used in the manufacturing of amphetamines. Pseudoephedrine shows anxiety, nervousness, dizziness, and excitability as its adverse effects.
Common brands that contain Pseudoephedrine are Actifed, Allegra, Aleve.
- Ephedrine is both direct, and indirect-acting adrenergic drug, whereas Pseudoephedrine is an indirect-acting adrenergic drug.
- Ephedrine is both alpha and beta-adrenergic agonist, on the other hand; Pseudoephedrine is mainly alpha-adrenergic agonist.
- Ephedrine is sympathomimetic amine, on the other hand, Pseudoephedrine is an isomer of Ephedrine.
- The main therapeutic use of Ephedrine is to raise blood pressure in patients of hypotension, whereas the main therapeutic use of pseudoephedrine is in respiratory system decongestion.
The conclusion of the above discussion is that Ephedrine is the prototype mixed-acting sympathomimetic drug and Pseudoephedrine being an isomer of Ephedrine shows approximately all pharmacological actions of Ephedrine and difference lies only in effectiveness of these pharmacological actions.