Caffeine

Related Terms

ADHD, amphetamines, analeptic stimulants, attention deficit hyperactivity disorder, caffeine, central nervous system, CNS, methylphenidate, methylxanthines, nicotine, stimulant, stimulant abuse, stimulants.

Background

Central nervous system (CNS) stimulants, also called psychomotor stimulants or uppers, are a class of drugs that speed up physical and mental processes. They temporarily make patients feel more alert and improve mood.
Stimulants are typically used to treat medical conditions such as attention-deficit hyperactivity disorder (ADHD), attention-deficit disorder (ADD), fatigue, and narcolepsy. Some stimulants have been used as appetite suppressants, although the safety of this use remains controversial.
Examples of CNS stimulants include amphetamines, such as methylphenidate (Ritalin?), methamphetamine (e.g. Desoxyn? or Desoxyn Gradumet?), caffeine (e.g. coffee or tea), nicotine (cigarettes or cigars), and the illegal drug cocaine.
Side effects of stimulants vary depending on the specific dose and type of drug. In general, side effects of short-term use may include anxiety, insomnia, dry mouth, depersonalization, feeling of euphoria, increased heartbeat, crying, dysphoria, decreased appetite, hyperventilation, irritability, depression, nervousness, paranoia, mood swings, restlessness, and shaking or trembling.
Most CNS stimulants are highly addictive. However, some newer drugs, such as modafinil (Provigil?) are less addictive.
Because stimulants are highly addictive and have euphoric effects on the brain, they are often abused and taken as recreational drugs. Long-term abuse of stimulants can cause changes in the brain and lead to serious health problems, including severe mental illness and memory loss.

Integrative therapies

Unclear or conflicting scientific evidence:
Acupressure, shiatsu: Acupressure is used around world for relaxation, wellness promotion, and the treatment of many health problems. Acupressure may improve alertness. Acupressure at stimulation and relaxation points may have different effects on alertness in a classroom setting. Further research is necessary to confirm these findings.
With proper training, acupressure appears to be safe if self-administered or administered by an experienced therapist. No serious long-term complications have been reported, according to scientific data. Hand nerve injury and herpes zoster ("shingles") cases have been reported after shiatsu massage. Forceful acupressure may cause bruising.
Acustimulation: Acustimulation is different than acupuncture. However, it uses Chinese acupuncture theory to locate points on the body where electrical stimulation is applied to reduce certain symptoms. Limited research suggests that acustimulation may help treat symptoms of fatigue. One study found that 15 minutes of transcutaneous electrical acupoint stimulation (TEAS) three times weekly for one month reduced fatigue and depressed mood, and increased sleep quality in patients receiving hemodialysis. However, the design of the study makes interpretation of the findings difficult. More studies are needed to determine whether acustimulation should be recommended for this use.
The only known side effect of acustimulation devices is slight skin irritation under the electrodes when the wristband is used. Switch wrists to avoid this reaction. Acustimulation devices should only be used on the designated area. Use cautiously with pacemakers. Avoid if the cause of medical symptoms is unknown. Keep acustimulation devices out of the reach of children.
Betel nut: Betel nuts come from the areca tree, a tropical palm tree. Betel nut use refers to a combination of three ingredients: the nut of the betel palm (Areca catechu), part of the Piper betel vine, and lime. Preliminary evidence suggests that betel nut may act as a stimulant. It is believed that small doses can lead to stimulant and euphoric effects, and betel nut chewing is popular due to these effects. Although all three ingredients may contribute to stimulant properties, most experts believe that chemicals in the betel nuts (alkaloids) may be responsible. Other substances that may be combined with betel nut chew, such as tobacco, may also contribute to its purported effects. However, chronic use of betel nuts may increase the risk of some cancers, and immediate effects can include worsening of asthma, high or low blood pressure, and abnormal heart rate.
Based on the known toxicities of betel nut use, the risks may outweigh any potential benefits. The use of tobacco as part of the chewed material may be a contributing factor in the oral carcinogenicity seen with betel. Esophageal and liver cancer have also been reported in limited numbers of betel users.
Avoid if allergic to betel nut or other plants of the Palmaceae family. Avoid with a history of asthma, Huntington's disease, urinary incontinence, mental illness, chest pain (angina), blood pressure disorders, irregular heartbeat (arrhythmia), heart attack, diabetes, kidney disease, low calcium levels, cancer, or thyroid disease. Avoid if pregnant or breastfeeding. Ingestion of 8-30 grams of areca nut at once may be deadly.
Ginseng: For more than 2,000 years, the roots of this slow-growing plant have been valued in Chinese medicine. A small amount of research using ginseng extract G115? (with or without multivitamins) reported improvements in patients with fatigue of various causes. However, these results are preliminary, and studies have not been high quality.
Avoid if allergic to ginseng or other plants in the Araliaceae family. There has been a report of a serious life-threatening skin reaction, possibly caused by contaminants in the ginseng formulation.
Iron: Iron is an essential mineral and an important component of proteins involved in oxygen transport and metabolism. Ferrous sulfate may improve symptoms of fatigue, primarily in women with borderline or low serum ferritin concentrations. Further research is needed to confirm these results.
Iron is a trace mineral, and hypersensitivity is unlikely. Avoid if allergic to products containing iron. Avoid excessive intake. Avoid iron supplements with blood disorders that require frequent blood transfusions. Use iron supplements cautiously with a history of kidney disease, intestinal disease, peptic ulcer disease, enteritis, colitis, pancreatitis, hepatitis, alcoholism, or with a history of heart disease. Use cautiously if planning to become pregnant or if older than 55 years of age. Pregnant or breastfeeding women should consult a healthcare professional before beginning iron supplementation.
L-carnitine: There are several promising reports on the use of L-carnitine for fatigue. However, additional study is warranted in this area.
Avoid if allergic to carnitine. Use cautiously with peripheral vascular disease, high blood pressure, alcohol-induced liver cirrhosis, or diabetes. Use cautiously in low birth weight infants and individuals on hemodialysis. Use cautiously if taking anticoagulants (blood thinners) or drugs that lower blood pressure (beta-blockers or calcium channel blockers). Avoid if pregnant or breastfeeding.
Physical therapy: Physical therapy has been suggested as a possible treatment for fatigue. It is used to improve mobility, restore function, reduce pain, and prevent further injury by using a variety of methods, including exercises, stretches, traction, electrical stimulation, and massage. Special tools, such as hot or cold packs, crutches, braces, treadmills, prosthetics, compression vests, computer-assisted feedback, lasers, and ultrasound, are used. There is inconclusive evidence on whether physical therapy may help reduce cancer-related fatigue. Additional study is needed in this area.
Not all physical therapy programs are suitable for everyone, and patients should discuss their medical history with their qualified healthcare professionals before beginning any treatments. Based on the available literature, physical therapy appears generally safe when practiced by a qualified physical therapist. Physical therapy may aggravate pre-existing conditions. Persistent pain and fractures of unknown origin have been reported. Physical therapy may increase the duration of pain or cause limitation of motion. Pain and anxiety may occur during the rehabilitation of patients with burns. Both morning stiffness and bone erosion have been reported in the physical therapy literature, although causality is unclear. Erectile dysfunction has also been reported. All therapies during pregnancy and breastfeeding should be discussed with a licensed obstetrician/gynecologist before initiation.
Sandalwood: Endemic in Indonesia, Australia, and the Indian peninsula, the Santalum album tree is the primary source of sandalwood and sandalwood oil. Both are used in Hindu religious ceremonies. Sandalwood is also a popular fragrance for incense and perfumes. Preliminary research indicates that sandalwood oil may increase alertness. However, more research is needed in this area.
Avoid if allergic or hypersensitive to sandalwood (Santalum album), its constituents, or related members of the Santalaceae family. Avoid if pregnant or breastfeeding.
Selenium: Selenium is a mineral found in soil, water, and some foods. Although it has been suggested that selenium may improve symptoms of fatigue, further research is needed to draw a firm conclusion in this area.
Avoid if allergic or sensitive to products containing selenium. Avoid with a history of non-melanoma skin cancer. Selenium is generally regarded as safe for pregnant or breastfeeding women. However, animal research reports that large doses of selenium may lead to birth defects.
Taurine: Energy drinks containing taurine, along with other ingredients, such as caffeine and glucuronolactone, have been available for about a decade. Overall, these drinks have been suggested to decrease sleepiness associated with driving, increase concentration, mood, and memory, and positively affect well-being and vitality. Further study is required to examine the effects of taurine alone.
Taurine is an amino acid, and it is unlikely that there are allergies related to this constituent. However, allergies may occur from multi-ingredient products that contain taurine. Use cautiously with high VLDL cholesterol, hypertriglyceridemia (an elevated level of fatty acid compounds in the blood), a history of low blood pressure, bleeding disorders, or potential for mania or epilepsy. Use cautiously if taking hypolipidemic(cholesterol-lowering), hypotensive (blood pressure-lowering), hypoglycemic (blood sugar-lowering), anti-platelet, or anticoagulant (blood thinning) medications. Avoid consumption of energy drinks containing taurine, caffeine, glucuronolactone, B vitamins, and other ingredients before consuming alcohol or exercising. Use cautiously if pregnant or breastfeeding. Taurine is a natural component of breast milk.
Vitamin B12: Vitamin B12 is a water-soluble vitamin that is commonly found in many foods, including fish, shellfish, meats, and dairy products. There is some evidence that intramuscular injections of vitamin B12 given twice per week might improve the general well-being and happiness of patients complaining of tiredness or fatigue. However, fatigue has many potential causes. Well-designed clinical trials are needed before a recommendation can be made.
Avoid vitamin B12 supplements if allergic or hypersensitive to cobalamin, cobalt, or any other product ingredients. Avoid with coronary stents (mesh tube that holds clogged arteries open) and Leber's disease. Use cautiously if undergoing angioplasty. Vitamin B12 is generally considered safe when taken in amounts that are not higher than the recommended dietary allowance (RDA).
Yoga: Yoga is an ancient system of relaxation, exercise, and healing with origins in Indian philosophy. Yoga has been described as "the union of mind, body, and spirit," which addresses physical, mental, intellectual, emotional, and spiritual dimensions towards an overall harmonious state of being. Preliminary studies in humans report that yoga may improve fatigue in adults. However, better-designed studies are needed before any conclusion can be made.
Yoga is generally considered to be safe in healthy individuals when practiced appropriately. Avoid some inverted poses with disc disease of the spine, fragile or atherosclerotic neck arteries, extremely high or low blood pressure, glaucoma, detachment of the retina, ear problems, severe osteoporosis, cervical spondylitis, or if at risk for blood clots. Certain yoga breathing techniques should be avoided in people with heart or lung disease. Use cautiously with a history of psychotic disorders. Yoga techniques are believed to be safe during pregnancy and breastfeeding when practiced under the guidance of expert instruction. However, poses that put pressure on the uterus, such as abdominal twists, should be avoided in pregnancy.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

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Types of central nervous system (cns) stimulants

Schedule I stimulants: Schedule I stimulants, including aminoxaphen (Aminorex?), cathinone, fenethylline (Captagon?), methcathinone, methylaminorex, and amphetamine variants (e.g. 3,4-methylenedioxymethamphetamine), have no medicinal value and have a high potential for abuse. Therefore, these drugs are not prescribed for medical conditions.
Schedule II stimulants: Schedule II stimulants also have a high abuse potential. Patients are likely to become psychologically and/or physically dependent on these drugs. Unless it is an emergency, prescriptions for schedule II stimulants must be made in writing and signed by a healthcare professional. If it is a medical emergency, the healthcare professional must provide written confirmation of the verbal prescription within 72 hours. Prescriptions for schedule II stimulants cannot be renewed. Examples of schedule II stimulants include dextroamphetamine (Dexedrine?), methamphetamine (Desoxyn?), methylphenidate (Ritalin?), phenmetrazine (Preludin?), and biphetamine. An illegal drug, called cocaine, also falls under this category.
Schedule III stimulants: Schedule III drugs are less likely to be abused than schedule I and II drugs. Healthcare professionals can give oral or written prescriptions and up to five renewals within six months. Examples of class III stimulants include benzphetamine (Didrex?), chlorphentermine, clortermine, and phendimetrazine tartrate (Plegine? or Prelu 2?).
Schedule IV stimulants: Schedule IV stimulants are less likely to be abused than schedule III stimulants. Healthcare professionals can give oral or written prescriptions and up to five renewals within six months. Examples of schedule IV stimulants include armodafinil (Nuvigil?), norpseudoephedrine, diethylpropion hydrochloride (Tenuate?), fencamfamin, fenproporex, phentermine (Fastin?, Lonamin?, or Adipex?), mazindol (Sanorex? or Mazanor?), mefenorex, modafinil (Provigil?), pipradrol, and sibutramine (Meridia?).
Schedule V stimulants: Schedule V stimulants, includes one class of drugs called pyrovalerone. These drugs are less likely to be abused than class IV stimulants. These drugs are regulated by the state. In some areas, a prescription may not be needed.

Uses

Appetite suppressant: A common side effect of central nervous system (CNS) stimulants is decreased appetite. For this reason, several stimulants that have low risks for abuse and dependency have been prescribed to help treat obesity. Examples of these drugs include dexfenfluramine, sibutramine, phentermine, fenfluramine, mazindol, diethylpropion, and fenproporex. However, stimulants cause limited weight loss because patients eventually develop tolerances to long-term treatment.
Many stimulants are unsafe when taken as appetite suppressants. Therefore, stimulants should only be taken to lose weight under the strict supervision of a qualified healthcare professional.
Attention disorders: Amphetamines, including methylphenidate (Ritalin?), dextroamphetamine (Dexedrine? or Dextrostat?), dextroamphetamine sustained-release capsules (Dexedrine Spansules?), benzphetamine (Didrex?), and lisdexamfetamine (Vyvanse?), are prescription medications that are taken by mouth to treat attention-deficit hyperactivity disorder (ADHD) and attention-deficit disorder (ADD).
Amphetamines help treat attention disorders by increasing attention and decreasing restlessness in patients who are overactive, unable to concentrate for very long or are easily distracted, and have unstable emotions. These medications are usually used in combination with social, educational, and psychological therapies.
A stronger, more potent type of amphetamine, called methamphetamine (Desoxyn? or Desoxyn Gradumet?), is sometimes used to treat ADHD.
Narcolepsy: Patients with narcolepsy, a condition that causes individuals to have sudden attacks of deep sleep or the uncontrollable desire to sleep, also receive stimulants. These drugs help narcoleptic patients stay awake during the day. Modafinil (Provigil?), a newer stimulant, is less addictive and better tolerated than other older types of stimulants.
However, some patients need treatment with methylphenidate (Ritalin?) or other types of amphetamines.
Fatigue: Caffeine is a stimulant that is found in coffee and various teas, soft drinks, and energy drinks. Caffeine is also available in pill form (e.g. No Doze?). Caffeine has been used to decrease fatigue. It has been shown to increase alertness, reduce sleepiness, enhance mental performance, and improve mood.
Methylphenidate (Ritalin? or Concerta?) has also been suggested as a possible treatment for chronic fatigue syndrome (CFS). This disorder causes extreme fatigue that does not improve with bed rest. Methylphenidate appears to increase and balance levels of the brain chemicals. Some research has shown that methylphenidate may help improve symptoms of fatigue and increase concentration in some people with CFS.
Recreational drug use: Many stimulants are used recreationally, for no medical purpose. However, abusing stimulants can lead to serious and potentially life-threatening health conditions.
For instance, nicotine is a stimulant that is found in tobacco products, such as cigarettes or cigars. The nicotine makes patients temporarily feel good or energized after smoking. Although this stimulant is legal, it can cause serious health problems, including cancer and emphysema.
Because methamphetamines are stronger, longer-lasting, and even more addictive than most other types of amphetamines, they are often abused. Methamphetamines can be smoked, injected, inhaled, or taken by mouth. Methamphetamine affects the brain and can create feelings of pleasure, increase energy, and elevated mood. Some individuals illegally create their own homemade methamphetamines, using various over-the-counter cold or allergy medicines, as well as household products, such as cleaning fluids and paint thinners. When used recreationally, methamphetamines, are often called chalk, crystal, glass, ice, meth, speed, and Tina.
Cocaine is an illegal CNS stimulant that is also commonly abused. The powdered, hydrochloride salt form of cocaine can either be snorted or dissolved in water and injected into a vein.
Crack is an unprocessed form of cocaine. Crack is cocaine that has not been neutralized to make the hydrochloride salt. This form of cocaine looks like a rock crystal. Individuals typically heat crack and inhale the vapors.

Side effects and safety

General: Central nervous system (CNS) stimulants should be taken under the supervision of a healthcare professional. Stimulants should not be taken for reasons other than their intended medicinal use.
Although CNS stimulants decrease appetite, they should not be used for weight loss or weight control, unless otherwise directed by a healthcare professional. When used for these purposes, many stimulants may cause dangerous side effects.
Side effects: Side effects of central nervous system stimulants (CNS) vary depending on the specific drug. In general, short-term use may cause side effects such as anxiety, insomnia, dry mouth, depersonalization, feeling of euphoria, increased heartbeat, crying, dysphoria, decreased appetite, hyperventilation, irritability, depression, nervousness, paranoia, mood swings, restlessness, and shaking or trembling.
Long-term use of stimulants may cause side effects such as difficulty breathing, dizziness, changes in mood, and increased or pounding heartbeat.
Patients should talk to their healthcare providers if they experience any of these symptoms.
Interactions: Patients should tell their healthcare providers if they have any other medical conditions or if they are taking any other drugs (prescription or over-the-counter), herbs, or supplements because they may interact with treatment.
Stimulants should not be taken with other drugs, herbs, or supplements that have stimulant properties because they may cause additive effects. Examples of herbs and supplements that act as stimulants include ephedra, caffeine, betel nut, DHEA, evening primrose oil, folate (folic acid), ginseng, glyconutrients, liver extract, sandalwood, and taurine.
Stimulants should not be taken with appetite suppressants. This combination produces additive results and may have serious adverse effects.
Pregnancy and breastfeeding: Animal studies suggest that CNS stimulants are not safe during pregnancy. These studies have shown that stimulants may increase the risk of birth defects and premature delivery.
Stimulants have been shown to pass into the breast milk. Stimulants are not recommended during breastfeeding.
Children: Long-term use of amphetamines, such as methylphenidate (Ritalin?), may cause serious side effects in children, including stunted growth and behavioral problems. Therefore, caregivers should discuss the potential health risks and benefits associated with stimulants before making a decision about a child's treatment.
Addiction: Central nervous system (CNS) stimulants are addictive, even if they are not abused. Many factors, including the patient's personal history, the type of stimulant that is being taken, the dose of the drug, and duration of use, influence how likely an individual is to become addicted. Therefore, patients with a history of drug dependence should use stimulants cautiously. Patients should take stimulants exactly as prescribed by their healthcare providers. Patients should also visit their healthcare professionals regularly to monitor their conditions.
Signs of addiction include a strong desire to continue taking the medication, desire to increase the dose of the drug, and withdrawal symptoms after the medication is stopped.
Abuse: CNS stimulants are abused if a patient takes them more frequently or at higher doses than recommended by a healthcare professional. Abuse also occurs if a patient uses stimulants for purposes other than the intended medical use.
Individuals who abuse CNS stimulants may become addicted quickly and usually require higher doses more frequently. When CNS stimulants are abused, they can cause serious adverse effects, including increased blood pressure, difficulty breathing, irregular heartbeat, and a wide range of psychological problems. Long-term abuse of stimulants changes the way the brain functions and may lead to severe mental disorders and memory loss. Research also suggests that stimulants impair the ability of specific brain circuits to change in response to experiences. This new evidence may help explain some of the behavioral and cognitive deficits that are often seen in people who are addicted to stimulants.
Withdrawal: Individuals who stop taking stimulants after they become addicted to them usually experience withdrawal symptoms. In general, symptoms of withdrawal may include irritability, headaches, nausea, vomiting, and mood swings.
The severity of withdrawal symptoms varies, depending on the specific drug. For instance, individuals who are addicted to caffeine may experience symptoms of fatigue or headaches when they stop drinking coffee. In contrast, individuals who abuse methamphetamines experience much more severe withdrawal symptoms that may even be life threatening. Examples of these symptoms include intense cravings for the drug, psychotic reactions, anxiety, moderate to severe depression, intense hunger, irritability, fatigue, mental confusion, and insomnia.

Overcoming addiction

Addiction can be difficult to overcome without help. Rehabilitation treatment programs are available to help patients recover from addiction. Programs are tailored to specific individuals. Treatment may include group therapy, motivational interviewing, family therapy, and one-on-one counseling. The duration of rehabilitation treatment usually lasts several months. However, treatment varies among individuals.
Unfortunately, relapse after treatment is common. Therefore, it is important to educate patients, as well as their friends and family members, about addiction. Individual, group, and family counseling may also help patients identify possible triggers for relapse. Support groups, such as Narcotics Anonymous, may help individuals stay sober once they have completed a rehabilitation program.
In addition, researchers have studied the use of newer, less addictive stimulants as a way to treat cocaine addictions. These new medications, such as modafinil (Provigil?), may allow cocaine addicts to gradually take less and less stimulants until they overcome their addictions.