Pharmacology of Caffeine and Nicotine

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Questions and Answers

What is the effect of low doses of nicotine on the CNS?

It causes central respiratory paralysis and severe hypotension.

It induces vasoconstriction that decreases coronary blood flow.

It produces some degree of euphoria and relaxation. (correct)

It causes stimulation of sympathetic ganglia and the adrenal medulla.

What is the mechanism of action of nicotine in low doses?

It causes ganglionic blockade.

It stimulates the parasympathetic nervous system.

It causes depolarization of ganglia. (correct)

It causes inhibition of the sympathetic nervous system.

What is a therapeutic use of caffeine?

Management of headaches. (correct)

Treatment of lung cancer.

Treatment of hypertension.

Treatment of cardiovascular disease.

What is a adverse effect of moderate doses of caffeine?

Insomnia, anxiety, and agitation. Signup and view all the answers

What is the effect of nicotine on the sympathetic nervous system?

It causes stimulation of the sympathetic nervous system. Signup and view all the answers

What is the therapeutic use of theophylline?

Treatment of asthma. Signup and view all the answers

What is the effect of stimulation of parasympathetic ganglia on the bowel?

Increased motor activity Signup and view all the answers

What is the mechanism of action of varenicline?

Partial agonist at neuronal nicotinic ACh receptors Signup and view all the answers

What is the main CNS effect of cocaine?

Euphoria Signup and view all the answers

What is a common adverse effect of nicotine?

Diarrhea Signup and view all the answers

What is the therapeutic use of varenicline?

Management of smoking cessation Signup and view all the answers

What is the mechanism of action of amphetamine?

Release of intracellular stores of catecholamines Signup and view all the answers

What is the mechanism of action of methylphenidate?

Transport inhibition of dopamine and NE Signup and view all the answers

What is the result of methylphenidate's action on the CNS?

Increased alertness and decreased fatigue Signup and view all the answers

How does methylphenidate act on the sympathetic nervous system?

Indirectly stimulating the receptors through NE release Signup and view all the answers

What is a common adverse effect of methylphenidate on the GI system?

Diarrhea Signup and view all the answers

What is a potential therapeutic use of methylphenidate?

Reducing appetite Signup and view all the answers

What is a potential adverse effect of methylphenidate on the cardiovascular system?

Hypertension Signup and view all the answers

Study Notes

Ganglionic Stimulants

Stimulation of parasympathetic ganglia increases motor activity of the bowel.
At higher doses, blood pressure falls and activity ceases in both the GIT and bladder musculature as a result of a nicotine-induced block of parasympathetic ganglia.

Varenicline

It is a partial agonist at neuronal nicotinic ACh receptors in the CNS.
It produces less euphoric effects than nicotine and is useful as an adjunct in the management of smoking cessation.

Cocaine

Its mechanism of action involves blockade of reuptake of the monoamines (norepinephrine, serotonin, and dopamine) into the presynaptic terminals.
This potentiates and prolongs the CNS and peripheral actions of these monoamines.
The prolongation of dopaminergic effects in the brain’s pleasure system (limbic system) produces the intense euphoria that cocaine initially causes.

Amphetamine

Types of amphetamine include dextro-amphetamine, meth-amphetamine, and 3,4-methylene-dioxy-meth-amphetamine.
It is a sympathetic amine that shows neurologic and clinical effects quite similar to those of cocaine.
Its effect on the CNS and peripheral nervous system is indirect, increasing the level of catecholamine NTs in synaptic spaces by releasing intracellular stores of catecholamines.

Caffeine

Caffeine and its derivatives relax the smooth muscles of the bronchioles.
Therapeutic uses of caffeine include relaxation of bronchioles in asthma patients and management of headaches with acetaminophen or aspirin.
Adverse effects of moderate doses of caffeine include insomnia, anxiety, and agitation, while high doses cause toxicity (manifested by vomiting and convulsions).

Nicotine

It is the active ingredient in tobacco and is not currently used therapeutically (except in smoking cessation therapy).
In low doses, nicotine causes ganglionic stimulation by depolarization, while high doses cause ganglionic blockade.
Actions of nicotine include:
- CNS: low doses produce euphoria and relaxation, improve attention, learning, problem-solving, and reaction time, while high doses result in central respiratory paralysis and severe hypotension.
- Peripheral effects: stimulation of sympathetic ganglia and the adrenal medulla increases blood pressure and heart rate, and inhibits monoamine oxidase (MAO) and reuptake transport.

Methylphenidate

It has CNS-stimulant properties similar to those of amphetamine and may also lead to abuse.
Its mechanism of action involves inhibiting dopamine and NE transport, increasing both dopamine and NE in the synaptic space.

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Description

Test your knowledge on the therapeutic uses and adverse effects of caffeine and nicotine, including their roles in asthma therapy, headache management, and their potential toxicities. Learn about the effects of these substances on the body and their interactions with other medications.