Pharmacology: Clonidine and Salbutamol Uses

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Questions and Answers

What is a common adverse effect of clonidine?

Hallucinations

Hypertension

Xerostomia (correct)

Increased heart rate

Which condition can amphetamines be used to treat?

Attention deficit disorder (correct)

Severe depression

Myocardial infarction

Chronic pain

What mechanism does cocaine primarily target?

Agonist of β2 receptors

Inhibition of dopamine transporter (correct)

Activation of adrenergic receptors

Inhibition of α2 receptors

Which of the following is NOT a side effect of amphetamines?

Increased appetite Signup and view all the answers

What type of agonists are salbutamol and terbutaline classified as?

Short-acting β2 agonists Signup and view all the answers

Using amphetamines can lead to which of the following withdrawal symptoms?

Extreme hunger Signup and view all the answers

What is a primary use of salmeterol?

Prophylaxis of asthma Signup and view all the answers

What adverse effects may result from the use of short-acting β2 agonists?

Tachycardia Signup and view all the answers

Which pharmacological action is associated with mixed-action adrenergic agonists like ephedrine?

Bronchodilation Signup and view all the answers

What is a notable adverse effect of phenoxybenzamine?

Postural hypotension Signup and view all the answers

Cocaine is primarily used for which of the following purposes?

Local anesthesia Signup and view all the answers

What is the mechanism of action for pseudoephedrine?

Release of stored norepinephrine Signup and view all the answers

Which of the following is an indication for the use of phentolamine?

Pheochromocytoma Signup and view all the answers

What could be a pharmacological effect of ephedrine?

Systolic blood pressure increase Signup and view all the answers

Which adverse effect is commonly associated with adrenergic antagonists like phentolamine?

Hypotension Signup and view all the answers

What type of drug is pseudoephedrine primarily used as?

Decongestant Signup and view all the answers

Which characteristic is NOT associated with catecholamines?

Greater access to the CNS Signup and view all the answers

What pharmacological action is primarily associated with β2 receptors in cardiovascular treatment?

Vasodilation at low doses Signup and view all the answers

Which drug is known to be a noncatecholamine?

Phenylephrine Signup and view all the answers

What is a possible adverse effect of using stimulants like epinephrine?

Increased blood glucose levels Signup and view all the answers

Which action is NOT characteristic of indirect-acting adrenergic agonists?

Stimulating α or β receptors directly Signup and view all the answers

What is a common use for amphetamines?

Management of attention deficit hyperactivity disorder (ADHD) Signup and view all the answers

Which of the following mechanisms describes how epinephrine affects the respiratory system?

Bronchodilation through β2 action Signup and view all the answers

What is the primary route of administration for epinephrine during emergency situations?

Intramuscularly or subcutaneously Signup and view all the answers

Study Notes

Nasal Decongestants

Induce mydriasis (dilation of pupils).

Clonidine

Agonist of presynaptic α2 receptors.
Uses include treating hypertension and alleviating addiction withdrawal symptoms (opiates, tobacco, benzodiazepines).
Adverse effects: lethargy, sedation, constipation, xerostomia.
Abrupt discontinuation can lead to rebound hypertension.

Short-Acting β2 Agonists (SABA)

Salbutamol (Albuterol) and terbutaline used for asthma management and to relax the uterus during premature labor.
Common adverse effects include tremor, tachycardia, arrhythmia, restlessness, apprehension, anxiety.

Long-Acting β Agonist (LABA)

Salmeterol is β2 selective and used for asthma prophylaxis.

Indirect-Acting Adrenergic Agonists

Mechanism: cause release, inhibit reuptake, or prevent degradation of epinephrine and norepinephrine.

Amphetamine

Increases release of catecholamines (dopamine, norepinephrine).
CNS effects: alertness, euphoria, increased concentration, anxiety, tremors, respiratory stimulation, decreased appetite, weak anticonvulsant effects.
Cardiovascular effects: mild blood pressure elevation.
Indications include hyperkinetic syndrome (ADHD), narcolepsy, depression, fatigue, and obesity.
Adverse effects: tremors, irritability, insomnia, potential for seizures and comas at high doses, weight loss, and abstinence syndrome (prolonged sleep, hunger, depression).

Cocaine

Mechanism: inhibits the transporters for dopamine, norepinephrine, and serotonin (DAT, NET, SERT).
Effects: increases heart rate and blood pressure, arousal, improved alertness, confidence, and well-being.
Chronic use leads to involuntary movements, stereotyped behaviors, paranoia, irritation, nausea, and vomiting.
Rarely used as a local anesthetic.

Mixed-Action Adrenergic Agonists

Ephedrine and pseudoephedrine increase norepinephrine release and directly stimulate both α and β receptors.
Poorly metabolized by COMT and MAO, primarily eliminated in urine.
Effects: raise blood pressure, bronchodilation, mild CNS stimulation.
Uses: pseudoephedrine for nasal and sinus congestion; ephedrine for hypotension.

Adrenergic Antagonists (Sympatholytics)

α-Blockers:
- Phenoxybenzamine: nonselective, irreversible α1 and α2 blocker; used for pheochromocytoma and Raynaud's disease; adverse effects include postural hypotension, nausea, and reflex tachycardia.
- Phentolamine: competitive α1 and α2 blocker; can cause postural hypotension, reflex cardiac stimulation; used for pheochromocytoma.

Catecholamines

Include epinephrine, norepinephrine, isoproterenol, and dopamine.
High potency for α and β receptor activation; rapidly inactivated by COMT and MAO; limited CNS penetration.

Non-Catecholamines

Examples: phenylephrine, ephedrine, amphetamine; less inactivation by COMT and MAO allowing improved CNS access.

Direct-Acting Adrenergic Agonists

Epinephrine stimulates both α and β receptors.
Cardiovascular actions: increases myocardial contractility (β1), heart rate (β1), and systemic blood pressure (α) while causing vasodilation in skeletal muscles (β2).
Respiratory: bronchodilation (β2 action).
Increases glucose metabolism and lipolysis.
Uses include treating bronchospasm, anaphylactic shock, cardiac arrest, and as a local anesthetic.
Pharmacokinetics: administered intramuscularly, subcutaneously, or intravenously, rapidly metabolized by MAO and COMT, urinary excretion.
Adverse effects: CNS responses like anxiety, fear, tension, headache, and tremors.

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Description

This quiz covers the pharmacological properties and uses of Clonidine, including its role as a presynaptic α2 agonist in treating hypertension and addiction withdrawal symptoms. Additionally, it addresses short-acting β2 agonists like Salbutamol, commonly used in asthma management. Test your knowledge on adverse effects and important considerations in discontinuation.