Pharmacotherapy Exam 1 September 27: Lecture 3 - Sympathomimetic Drugs, ETC

Myasthenia gravis is a disease in which the body's immune system mistakenly attacks and destroys nicotinic receptors, which are responsible for transmitting nerve signals to muscles. Drugs ending in -stigmine, such as acetylcholinesterase inhibitors, can help treat the symptoms of myasthenia gravis by increasing the levels of acetylcholine, a neurotransmitter that is crucial for muscle function. Therefore, the given answer is correct as myasthenia gravis is one of the diseases that can be treated with drugs ending in -stigmine.

Epinephrine, Norepinephrine, and Phenylephrine select α1 receptors agonistically. These drugs bind to α1 receptors and activate them, leading to vasoconstriction and increased blood pressure.

The drugs LABETALOL, CARVEDILOL, PHENTOLAMINE, PHENOXYBENZAMINE, and TAMSULOSIN select α1 receptors antagonistically. This means that they block or inhibit the activity of the α1 receptors.

Ephedrine and Pseudo-Ephedrine are referred to as mixed acting drugs because they exhibit both antagonistic and stimulatory effects on their receptor simultaneously. This means that while they bind to the receptor in an antagonistic manner, they also stimulate the receptor at the same time. This dual action of the drugs on the receptor is what classifies them as mixed acting drugs.

Clonidine is able to affect the heart rate by stimulating α2 receptors instead of β receptors because it has the ability to cross the blood-brain barrier. This means that the alpha receptors it binds to are located in the central nervous system (CNS) rather than on the effector organ, which in this case is the heart. By binding to α2 receptors in the CNS, clonidine can modulate the release of norepinephrine, resulting in a decrease in sympathetic outflow and ultimately leading to a decrease in heart rate.