Pharmacology of Midodrine

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Questions and Answers

What is the primary mechanism through which the drug causes tachyphylaxis?

Inhibition of norepinephrine reuptake

Depletion of vesicles storing norepinephrine (NE) (correct)

Enhanced receptor sensitivity

Increased release of catecholamines

What is the absorption route for this synthetic non-catecholamine drug?

Topical

Intravenous

Intramuscular

Oral (correct)

Which of the following terms best describes the effect of tachyphylaxis?

Reduction of response after repeated administration (correct)

Enhanced drug effectiveness upon repeated doses

Consistent response regardless of dosing frequency

Increase in tolerance to the drug

Which of the following is NOT a characteristic of the drug described in the content?

It requires parenteral administration Signup and view all the answers

What is the outcome of repeated administration of the drug mentioned?

The drug leads to a diminished response over time Signup and view all the answers

What is a primary advantage of using the mentioned substance topically for cardiac conditions?

It minimizes the risk of renal impairment Signup and view all the answers

In what scenario is the substance suggested to be particularly beneficial?

After cardiac surgery in acute conditions Signup and view all the answers

What is a potential application of the substance mentioned in the context?

Haemostatic management during local anesthetic procedures Signup and view all the answers

What condition does the substance aim to address in connection with renal impairment?

Maintenance of renal function during treatments Signup and view all the answers

Which aspect is most likely to hinder the use of the substance in surgical settings?

Potential for systemic side effects Signup and view all the answers

Which of the following substances primarily acts as a selective agonist for β2 adrenergic receptors?

Salbutamol Signup and view all the answers

What is the mechanism of action of Adrenaline when activating the α1 adrenergic receptors?

Vasoconstriction of blood vessels Signup and view all the answers

What type of action does Midodrine primarily exhibit in the body?

Vasoconstriction Signup and view all the answers

Which of the following is NOT an action of Amphetamine?

Vasodilation effects Signup and view all the answers

Which of the following is true regarding the pharmacological classification of Midodrine?

It is categorized as a vasoconstrictor agent. Signup and view all the answers

Which of the following effects is least likely associated with Midodrine usage?

Dopaminergic effects Signup and view all the answers

Which drug would likely be used to induce uterine relaxation during preterm labor?

Ritodrine Signup and view all the answers

Which synthetic compound is primarily known for its action as a selective α1 agonist?

Phenylephrine Signup and view all the answers

How does Midodrine primarily facilitate its therapeutic effects?

By inducing vasoconstriction Signup and view all the answers

What is a potential misconception regarding the therapeutic action of Midodrine?

That it has primarily diuretic properties. Signup and view all the answers

What is the primary physiological effect of noradrenaline on heart rate when its action is greater on α receptors than β1 receptors?

Decreased heart rate due to increased force of contraction Signup and view all the answers

Which receptor activation is primarily responsible for causing severe vasoconstriction in the context provided?

α1 receptors Signup and view all the answers

What physiological response is typically associated with severe vasoconstriction?

Bradycardia Signup and view all the answers

In what state does the body find itself when there is a predominance of α1 receptor activation over β1 receptor effects?

Hypertensive state Signup and view all the answers

What occurs to the heart rate when there is a forceful contraction of the heart induced by noradrenaline alongside vasoconstriction?

Heart rate decreases Signup and view all the answers

Study Notes

Drug Profile: Midodrine

A dopaminergic drug primarily indicated for vasoconstriction without renal impairment effects.
Preferred for its use in acute myocardial situations post-cardiac surgery.

Administration & Absorption

Administered orally; classified as a synthetic non-catecholamine.
Absorption allows for effective systemic delivery.

Mechanism of Action

Acts on D1 receptors to promote vasoconstriction.
Causes depletion of norepinephrine (NE) vesicles, impacting overall response.

Side Effects & Considerations

May lead to tachyphylaxis, a phenomenon where response to the drug diminishes with repeated use.
Consider reflex bradycardia as a notable side effect due to strong α1 receptor activity alongside vasoconstriction.

Other stimulants and sympathomimetics include Ephedrine, Amphetamine, Phenylephrine, Methoxamine, Salbutamol, and Ritodrine, each with varying receptor activity and effects.
Noradrenaline primarily targets α-adrenergic receptors (α > β1), affecting contraction force while reducing heart rate.

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Description

Explore the essential pharmacological aspects of Midodrine, a dopaminergic drug known for its vasoconstrictive properties. This quiz covers the drug's mechanism of action, administration, side effects, and related compounds essential for understanding its clinical uses.