Stimulants

Part 2 Caffeine & It’s Relatives

(or the “Xanthines”)

Xanthines

• Found in about ~60 plant species, many of which contain a combination of xanthines

• Mild stimulants affecting body & brain

– caffeine (strongest CNS action)

– theophylline (strongest PNS action)

– theobromine

– FYI - aminophylline, a theophylline derivative, is widely used medically

Body Effects

• Increased HR & BP; release of adrenaline

• Increased salivation & GI secretions

• Bronchodilation & increased respiration

• Increased metabolism & increases temp.

• Increased urination (diuretic effect)

• Constricts brain blood vessels; dilates other vessels

CNS Effects

• Increased wakefulness, decreased fatigue

• Increased attention, decreased boredom

• Mild mood elevation

• Increased motor activity

• Increased response to sensory stimuli

• Shortens reaction time

Caffeine’s Action

• Effects begin in ~ 30 minutes but peak after 2 hrs. ED50 = 100-125 mg.

• Half-life is ~3.5-5 hours in most adults (less in smokers, much longer in infants, elderly & during pregnancy & in those taking SSRIs)

• Blocks receptors for a natural calming/sleep-promoting compound in the body: adenosine. Also indirectly increases DA activity (rewarding) and NE (stimulating).

Caffeinism (too much)

• restless, anxious, irritable, agitated, panic attack in some

• insomnia

• muscle tension & tremors

• rapid, sometimes irregular HR

• flushed, hot and sweaty

• nausea; increased urination

• sensory disturbances (visual, tinnitus, increased awareness of body sensations)

Withdrawal

• Regular use does produce moderate tolerance and dependence

• Beginning about 18 hrs after your last dose:

• throbbing headache, worsens with exercise

• fatigue, no energy, yawning

• difficulty concentrating, slowed performance

• glum, irritable, mild depression

Health Risks?

• Primary risks to those with pre-existing conditions (e.g. may increase BP in those prone to hypertension)

• Heartburn due to gastric reflux, aggravates ulcers

• May trigger panic attacks in some

• High levels may increase risk of miscarriage or decrease growth of fetus

Nicotine

A potent (average cig. contains .5-2 mg) and toxic (LD= ~60 mg.) with an even worse route of administration (Smoking causes 1 out of 5 deaths in US each year (~450,000 per year))

Nicotine Basics

• Non-tolerant user experiences symptoms of mild nicotine poisoning:

– Pale, sweaty

– Dizzy, weak in the knees

– Nausea, intestinal cramps

– Sympathetic & CNS arousal

• Sufficient nicotine could kill you (seizures, respiratory paralysis) (kids, pets and farmers most at risk)

Myth of the Safer Cigarette

n To maintain customer satisfaction, filtered cigarettes have to use a high T/N tobacco, counteracting the benefit of the filter and raising the toxicity of sidestream smoke.

Myth of the Safer Cigarette

n “Low T/N” figures are based on smoke drawn by smoking machine. Holes in sides of filter allowing air to be drawn in with smoke, diluting it. Smokers block those holes with fingers or lips so get a higher proportion of smoke, decreasing or eliminating the benefits of low T/N.

Smokers unconsciously adjust their pattern of smoking to maintain certain levels of nicotine despite the content in a particular cigarette (e.g. smoke more cigarettes, more puffs per cigarette, smoke further down on the butt).

Risk: Cardiovascular Disease

n Risk of coronary heart disease doubles (quadruples in heavy smokers)

n Nicotine increases HR & BP

n At the same time there is less blood getting to the heart, a greater risk of clotting, and an increase in serum cholesterol and fatty deposits

Risk: Respiratory Disease

n Lung Cancer

n Chronic Obstructive Lung Diseases like emphysema & bronchitis

n Increased respiratory infections

Fetal Tobacco Syndrome

n Smoking during pregnancy produces a dose-dependent decrease in oxygen to the baby, resulting in:

– shorter, lighter babies with smaller heads

– dose-related risk of miscarriage, placental problems, bleeding, stillbirth, prematurity, neonatal death

– some studies show small but consistent increases in learning difficulties and hyperactivity in those kids; increased SIDS

Why People Smoke

n For stimulating effect

n For relaxing effects

n For positive mood change

n In response to situational and social cues

n Nervous habit, occupy hands/mouth

n A smoking ritual

n Monitor when, where, & why you smoke & specifically avoid or address those situations when you are quitting

Withdrawal Symptoms

n Drowsy, depressed, decreased concentration, brain less aroused

n Restlessness, anxiety, irritability

n Headache, sweating, decreased HR & metabolism, GI complaints, sleep disturbances

n Craving

n Behavioral habits may be even more important than withdrawal

Pharmacological Approaches

n Nicotine substitutes

– Nicorette chewing gum

– Nicotine patch

– Nicotine inhaler

– Nicotine nasal spray

n Avoid withdrawal symptoms while breaking behavioral habit

n Easier way to “taper off” for some

Zyban

Antidepressant buproprion (same as Wellbutrin) seems to relieve the mood changes of withdrawal and reduce craving, leading to increases in both short term and long-term smoking cessation. Do not have to be depressed to benefit from Zyban during quitting.

Tips For Quitting on Your Own

n Learn why you smoke – write down when & where you smoke and what you’re feeling on an index card you keep in your smokes for 2 weeks

n Cutback by about one-half. Smoke those cigarettes at pre-arranged times.

n Then go cold turkey. Avoid smoking situations. Choose as unstressful a time as you can. Hang around non-smokers.

n Consider relapses part of the process and immediately return to your “program”.

n Use pharmacological aids!

Some Behavioral Approaches

n Stimulus control (avoid smoking situations; make tobacco less available)

n Visualize smoking consequences – think about your dirty black lungs& shrunken coronary arteries each time you light up