Methylxanthines

Caffeine is a substance naturally found in foods and drinks such a coffee and chocolate and is a stimulant that increases alertness. Tolerance to caffeine rapidly develops and withdrawal effects are noticeable including fatigue and headaches.  Caffeine has indication for the treatment of neonatal apnea.  Another methylxanthine, theophylline, is used in the treatment of asthma due to its bronchodilation effects.  

Class Drugs

• Caffeine

• Theophylline

Class Mechanism of Action

Multiple potential mechanisms

• Blockade of adenosine receptors

• Increase in cAMP and cGMP

Class Application/Actions

Stimulant

• Decreases fatigue and increases mental alertness

Stimulates the cerebral cortex

• Tolerance rapidly develops

Asthma (Theophylline)

• Smooth muscle relaxation of bronchioles

Cardiovascular

• Large doses have positive inotropic and chronotropic effects

Diuretic

• Increases urinary output

Class Adverse Effects

Anxiety

Insomnia

Tremors

In overdose

• Emesis, convulsions, cardiac arrhythmias

Withdrawal syndrome

• Fatigue

• Headaches

Drug Table

Drug Name	Application	Comments	Image
Caffeine	Neonatal apnea		"Coffee"
Theophylline	Asthma	Adverse Effects; -Narrow therapeutic index; -Numerous drug interactions (CYP1A2 and CYP3A4)	"Theo Filling"