Caffeine

• mild stimulationcan be defined as any changes in a person's energy levels which are interpreted as stimulating and encouraging when it comes to movement and physical activities such as running, walking, cleaning, socializing, dancing, and climbing More,
• alertness,
• reduces feelings of tiredness ⁶.

• sleeplessness,
• tension,
• palpitations,
• anxiousness ⁶.

Caffeine is found in drinks like coffee, tea, and mate (a tea drunk in Argentina). Caffeine can also be found in ‘energy drinks’ which have high caffeine content, and some soft drinks. In Europe, drinks (not based on coffee or tea) with a caffeine content of more than 150 mg per litre, have to be labelled as high caffeine content with the amount of caffeine on it.

Shops also sell caffeine shots, which are small amounts of sugary drink with a high caffeine content. Like alcohol shots, it is easy to drink a lot of these quickly before realising you have had too much.

It is common to become addicted to caffeinated drinks, in that stopping use will lead to withdrawal symptoms, although most people would not find it difficult to stop caffeine use.

Caffeine is often listed as a flavouring on soft drinks, although it may not be the case that caffeine adds to the taste of the drink, rather it increases the desire to consume it ¹.

Over 50% of Americans drink coffee daily. The amount of caffeine a cup of coffee contains varies a great deal, depending on the strength of the particular brand of coffee, and the method of brewing – which determines how concentrated the caffeine is. And, don’t forget, the size of your coffee cup will also determine how much caffeine it contains.

The amount of caffeine you actually consume will depend, then, on the strength of your coffee, and the size of the cup. For example, a shot of expresso, the strongest type of coffee, contains about 50mg of caffeine per fl oz, but as a shot is only 2 fl oz, it would give you 100mg of caffeine, the same amount as an 8 fl oz cup of brewed coffee. Instant coffee is weaker at about 50mg per 8 fl oz cup ⁷.

The many different types of tea vary from containing high levels of caffeine, to herbal teas which contain no caffeine at all.

Regular tea, usually an Orange Pekoe or Black tea blend, contain about the same amount of caffeine as instant coffee – 50 mg per 8 fl oz cup. But you can always steep your tea for longer, and get a stronger beverage, so the amount of caffeine in a cup of tea varies from about 20mg to 80mg per 8 fl oz cup.

There is some variation among different types of tea, with Chai ranging from about 60-120mg of caffeine per 8 fl oz cup, Assam black tea about 80mg per 8 fl oz cup, Earl Grey and Darjeeling teas containing average amounts of caffeine at around 50mg, Oolong having only 40mg, Green tea, 25mg, and White tea, 15mg ⁷.

The amount of caffeine in chocolate varies, according to the brand and the type of chocolate. On average, milk chocolate contains about 18mg of caffeine per 100g. That doesn’t seem like much, but for a chocoholic, it can easily add up.

Dark chocolate contains much more caffeine, with dark chocolate containing upwards of 70mg of caffeine per 100g bar – almost as much as you get in a cup of coffee.

Some manufacturers add extra caffeine to chocolate to produce a stronger caffeine hit – typically around 100mg caffeine per piece, about the same amount as you would get in a shot of expresso coffee. Other types of caffeine-loaded sweets, mints and gum are available.

White chocolate doesn’t usually contain caffeine ⁷.

Soft drinks, typically marketed to children, often contain rather a lot of caffeine. Cola is the most well-known source of caffeine, containing from about 30mg – 60mg caffeine per 330ml can, depending on the brand. We are reminded of the similarity between cola and coffee by the distinctive brown colouring, so many parents make the mistake of thinking lemonade type clear soft drinks don’t contain caffeine, although many of them do. Some contain the same amount as cola, or even more.

Iced tea and root beer are also common sources of caffeine, containing similar amounts to regular tea, often consumed in larger amounts. However, some brands of soft drinks do not contain any caffeine, or contain lower amounts, so it is worth checking the label to see ⁷.

Caffeine tablets are legal and are used to increase alertness. Some beliefs about their effectiveness, for example in improving exam performance, are not wholly supported by the evidence. They do not replace the need for sleep, in fact a nap can be much more beneficial ¹.

Analysis of drug samples show that caffeine is commonly added, which adds bulk cheaply and so increases the dealers’ profits. Caffeine has been identified in heroin, where it may make the drug easier to smoke. It is commonly added to stimulanta drug that acts on the Central Nervous System, increasing some rates of function such as heart-rate drugs like cocaine, amphetamines (speed) and MDMASee Ecstasy More (ecstasy) where its stimulanta drug that acts on the Central Nervous System, increasing some rates of function such as heart-rate effects may disguise how impure the drug is, and may also increase the risks ¹.

‘Legal highs’ are not effectively regulated, meaning that their content can be at least as unpredictable as illegal drugs can. A study testing seven ‘legal highs’, none of which were labelled as containing caffeine, found that caffeine was actually the only psychoactive drug in them. Four of them were almost all caffeine, and two were almost half caffeine. Taking a large quantity of these substances could cause a caffeine overdose ¹.

• oral – 5 – 10 minutes ⁸.
• all ROA’sroute of administration - where the drug gets into your body – 5 – 10 minutes ¹⁰.

• oral – 15 – 45 minutes (dependant on form and stomach contents) ¹¹.

• oral – 1 – 2 hours ¹².

• oral – 1.5 – 5 hours ⁸, ¹¹.
• all ROA’sroute of administration - where the drug gets into your body – 1.5 – 5 hours ¹⁰.

• oral – 2 – 3 hours ¹¹.

• oral – 6 – 24 hours ¹².
• all ROA’sroute of administration - where the drug gets into your body – 3 – 4 hours ¹⁰.

Caffeine, a naturally occurring xanthine derivative like theobromine and the bronchodilator theophylline, is used as a CNSthe Central Nervous System, upon which certain drugs act stimulanta drug that acts on the Central Nervous System, increasing some rates of function such as heart-rate, mild diuretic, and respiratory stimulanta drug that acts on the Central Nervous System, increasing some rates of function such as heart-rate (in neonates with apnoeaSuspension of breathing. During apnoea, there is no movement of the muscles of inhalation, and the volume of the lungs initially remains unchanged. More of prematurity). Often combined with analgesics or with ergot alkaloids, caffeine is used to treat migraine and other headache types. OTCdrugs that are available as medicines in pharmacies without a prescription; the mnemonic stands for over-the-counter, meaning you can buy it easily caffeine is available to treat drowsiness or mild water-weight gain ¹⁵.

Caffeine is metabolised in the liver by the cytochrome P450 oxidase enzyme system (specifically, the CYP1A2 isozyme) into three metabolic dimethylxanthines: paraxanthine, theobromine and theophylline ¹⁶.

• Paraxanthine increases lipolysisA non-surgical treatment which breaks down fat cells and these cells are then excreted by the body. More, leading to elevated glycerol and free fatty acid levels in the blood plasma.
• Theobromine dilates blood vessels and increases urine volume. Theobromine is also the principal alkaloid in cocoa, and therefore chocolate.
• Theophylline relaxes smooth muscles of the bronchi, and is used to treat asthma ¹⁶.

Each of these caffeine metabolites is further metabolised into various methyluric acids and then excreted in the urine ¹⁶.

Hepatic cytochrome P450 1A2 (CYP 1A2) is involved in caffeine biotransformation. About 80% of a dose of caffeine is metabolised to paraxanthine (1,7-dimethylxanthine), 10% to theobromine (3,7-dimethylxanthine), and 4% to theophylline (1,3-dimethylxanthine) ¹⁷.

Caffeine stimulates medullary, vagal, vasomotor, and respiratory centers, promoting bradycardiawhen the heart beats very slowly, vasoconstrictionnarrowing of the blood vessels resulting from contraction of the muscular wall of the vessels (in particular the large arteries and small arterioles), and increased respiratory rate. This action was previously believed to be due primarily to increased intracellular cyclic 3′,5′-adenosine monophosphate (cyclic AMP) following inhibition of phosphodiesterase, the enzyme that degrades cyclic AMP. It is now thought that xanthines such as caffeine act as antagonists at adenosine-receptors within the plasma membrane of virtually every cell. As adenosine acts as an autocoid, inhibiting the release of neurotransmitters from presynaptic sites but augmenting the actions of norepinephrine or angiotensin, antagonism of adenosine receptorsnerve endings that sense changes in the body More promotes neurotransmitter release. This explains the stimulatory effects of caffeine. Blockade of the adenosine A1 receptor in the heart leads to the accelerated, pronounced “pounding” of the heart upon caffeine intake

Readily absorbed after oral or parenteral administration. The peak plasma level for caffeine range from 6 – 10mg/L and the mean time to reach peak concentration ranged from 30 minutes to 2 hours ¹⁷.

Caffeine from coffee or other beverages is absorbed by the stomach and small intestine within 45 minutes of ingestion and then distributed throughout all tissues of the body ¹⁶.

Orally it varies from around 77% – 99% ¹⁰.

3 to 7 hours in adults, 65 to 130 hours in neonates ¹⁷.

In young infants, the elimination of caffeine is much slower than that in adults due to immature hepatic and/or renal function ¹⁷.

The LD50the amount of a material, given all at once, which causes the death of 50% (one half) of a group of test animals. The LD50 is one way to measure the short-term poisoning potential (acute toxicity) of a material of caffeine is 190 milligrams per kilogram ⁸.

Extreme overdose can result in death ¹⁸, ¹⁹. The LD50the amount of a material, given all at once, which causes the death of 50% (one half) of a group of test animals. The LD50 is one way to measure the short-term poisoning potential (acute toxicity) of a material given orally is 192 milligrams per kilogram in rats. The LD50the amount of a material, given all at once, which causes the death of 50% (one half) of a group of test animals. The LD50 is one way to measure the short-term poisoning potential (acute toxicity) of a material of caffeine in humans is dependent on individual sensitivity, but is estimated to be about 150 to 200 milligrams per kilogram of body mass or roughly 80 to 100 cups of coffee for an average adult ²⁰. Though achieving lethal dose of caffeine would be difficult with regular coffee, it is easier to reach high doses with caffeine pills, and the lethal dose can be lower in individuals whose ability to metabolise caffeine is impaired ¹².

127 mg/kg (orally in mice) ¹⁷.

• full tolerancethis is the process by which the receptors in your brain become habituated to the action of a drug. When tolerance is reached, more of the drug is required to achieve the same effect. With benzodiazepines, and probably with many other classes of drugs as well, tolerance is virtually always associated with some degree of physical dependence. If you find that you are experiencing tolerance, this is a clear warning sign that you may have formed a dependence. More is reached develops with prolonged and repeated use,
• decreases to half after 3 – 7 days,
• returns to baseline after 1 – 2 weeks ¹².

The following effects may be experienced between 5 to 30 minutes after consuming caffeine, and may continue for up to 12 hours –

• feeling more alert and active,
• restlessness,
• excitability,
• dizziness,
• anxiety,
• irritability,
• dehydration,
• needing to urinate more often,
• higher body temperature,
• faster breathing and heart rate,
• headache,
• lack of concentration,
• stomach pains ²², ⁵.

Children and young people who consume energy drinks containing caffeine may also suffer from –

• sleep problems,
• bed-wetting,
• anxiety ²³, ⁵.

Regular, heavy use of caffeine (such as more than 4 cups of coffee a day) may eventually cause –

• osteoporosis,
• high blood pressure and heart disease,
• heartburn,
• ulcers,
• difficulty sleeping,
• infertility (in men and women),
• anxiety,
• depression,
• needing to use more to get the same effect,
• dependence on caffeine ⁴, ⁵.

• bronchodilation,
• stamina enhancement,
• stimulationcan be defined as any changes in a person's energy levels which are interpreted as stimulating and encouraging when it comes to movement and physical activities such as running, walking, cleaning, socializing, dancing, and climbing More,
• tactile enhancement,
• appetite suppression,
• dizziness,
• frequent urination,
• increased blood pressure,
• increased heart rate,
• increased perspiration,
• nausea,
• teeth grinding,
• vasoconstrictionnarrowing of the blood vessels resulting from contraction of the muscular wall of the vessels (in particular the large arteries and small arterioles) ¹².

• anxiety,
• cognitive euphoriastate of intense well-being, happiness, and excitement More,
• compulsive redosing,
• depression,
• irritability,
• analysis enhancementbest described as a subtle to distinct enhancement of one's overall ability to process information and logically or creatively analyse concepts, ideas and scenarios. The experience of this leads onto deep and complex states of contemplation which often result in an abundance of new and insightful ideas. This gives the person a powerful ability to dissect and rationally analyse concepts and problems, allowing them to gain insights and reach new conclusions, perspectives and solutions which would have been otherwise difficult to conceive of. More,
• focus enhancement,
• increased libido,
• memory enhancement,
• motivation enhancement,
• stamina enhancement,
• thought acceleration,
• wakefulness,
• cognitive fatiguethe decline in the ability to think effectively and maintain focus. More,
• motivation suppression,
• thought deceleration ¹².

• anxiety,
• cognitive fatiguethe decline in the ability to think effectively and maintain focus. More,
• depression,
• irritability,
• motivation suppression,
• thought deceleration,
• wakefulness ¹².

Some people consume drinks with caffeine so that they can continue working or studying at night. However, the after-effect is that they will feel tired and lethargic the next day ⁵.

In higher doses, caffeine can cause panicked thinking, racing thoughts, and an uncomfortable bodyload. With ordinary use, people tend to experience little to no after-effects from caffeine alone ⁸.

• stimulationcan be defined as any changes in a person's energy levels which are interpreted as stimulating and encouraging when it comes to movement and physical activities such as running, walking, cleaning, socializing, dancing, and climbing More,
• mild euphoriafeelings of joy and happiness,
• increase in cognitive abilities,
• increased drive,
• increased focus ⁸.

• basal metabolic rate increase,
• decreased appetite,
• increased perspiration,
• respiratory rate increase,
• heart rate increase,
• diuretic effects ⁸.

• anxiety,
• jitters,
• feelings of discomfort ⁸.

• tiredness (crash),
• irritability ⁸.

If a large amount of caffeine is consumed it could also cause an overdose.

• tremors,
• nausea,
• vomiting,
• very fast and irregular heart rate,
• confusiontrouble focusing, slow or disorganised thinking, poor short-term memory, unsure of time or place, or having difficulty following a conversation,
• panic attack,
• seizuresthe outward effect can vary from uncontrolled jerking movement (tonic-clonic seizure) to as subtle as a momentary loss of awareness More ²⁴, ⁵.

It is possible to die from having too much caffeine, but this is extremely rare. This would usually only happen if 5 – 10 grams of caffeine (or 80 cups of strong coffee) were consumed one after the other ⁴.

In small children, caffeine poisoning can happen if a lower amount, such as around 1 gram of caffeine (equal to around 12 energy drinks) is consumed one after the other ²⁵, ⁵.

Usually in excess of about 300 milligrams, dependent on body weight and level of caffeine tolerancethis is the process by which the receptors in your brain become habituated to the action of a drug. When tolerance is reached, more of the drug is required to achieve the same effect. With benzodiazepines, and probably with many other classes of drugs as well, tolerance is virtually always associated with some degree of physical dependence. If you find that you are experiencing tolerance, this is a clear warning sign that you may have formed a dependence. More, can result in a state of central nervous systembrain and spinal cord over-stimulation called caffeine intoxication (“caffeine jitters”).

The symptoms of caffeine intoxication are similar to overdoses of other stimulants and may include –

• restlessness,
• nervousness,
• excitement,
• insomniadifficulty in going to sleep or in getting enough sleep,
• facial flushing,
• increased urination,
• gastrointestinal disturbances,
• muscle twitching,
• irritability ⁶.

In cases of much larger overdoses –

• mania,
• disorientation,
• hallucinationswhere someone sees, hears, smells, tastes or feels things that don't exist outside of their mind,
• psychosis ⁶.

In cases of extreme overdose, death can result. Achieving a lethal dose with caffeine would be difficult with regular coffee, but there have been reported deaths from overdosing on caffeine pills ⁶.

• restlessness,
• acute anxiety,
• dependence ⁶.

Caffeine is a drug that in large amounts, especially over an extended period of time, can lead to a condition termed “caffeinism.” Caffeinism usually combines physical addiction with a wide range of unpleasant physical and mental conditions including nervousness, irritability, anxiety, tremulousness, muscle twitching (hyperreflexia), insomniadifficulty in going to sleep or in getting enough sleep, and heart palpitations ²⁶.

• DOx – High doses of caffeine may cause anxiety which is less manageable when tripping, and since both are stimulating it may cause some physical discomfort.
• NBOMes – Caffiene can bring out the natural stimulationcan be defined as any changes in a person's energy levels which are interpreted as stimulating and encouraging when it comes to movement and physical activities such as running, walking, cleaning, socializing, dancing, and climbing More from psychedelic drugs to make it uncomfortable. High doses can cause anxiety which is hard to handle while tripping.
• αMT – High doses of caffeine may cause anxiety which is less manageable when tripping, and since both are stimulating the combination may cause some physical discomfort.
• PCP – Details of this combination are not well understood but PCP generally interacts in an unpredictable manner.
• Amphetamines – This combination of stimulants is not generally necessary and may increase strain on the heart, as well as potentially causing anxiety and greater physical discomfort.
• MDMASee Ecstasy More – Caffeine is not really necessary with MDMASee Ecstasy More and increases any neurotoxic effects from MDMASee Ecstasy More.
• Cocaine – Both stimulants, risk of tachycardiarapid pulse rate, hypertensionhigh blood pressure, and in extreme cases heart failure ¹⁰.

The hallmark caffeine withdrawal symptom is a severe headache, which bears many similarities to a migraine headache. Like migraines, it is accompanied by vasodilationwidening of the blood vessels in the head and neck, and like migraines, it can take the form of hemicrania, or a headache on only one side of the head.

Many of the other caffeine withdrawal symptoms are similar to those experienced during a migraine.

Study after study has shown that the easiest and most effective way to relieve a caffeine withdrawal headache is by taking more caffeine. But be careful with how much. Check out the amount of caffeine in common foods and drinks, and make sure you don’t increase your caffeine intake beyond the amount you were using before, as this will build up your tolerancethis is the process by which the receptors in your brain become habituated to the action of a drug. When tolerance is reached, more of the drug is required to achieve the same effect. With benzodiazepines, and probably with many other classes of drugs as well, tolerance is virtually always associated with some degree of physical dependence. If you find that you are experiencing tolerance, this is a clear warning sign that you may have formed a dependence. More, which will potentially feed your caffeine addiction ²⁷.

Nausea is a much more common caffeine withdrawal symptom than vomiting, but both are recognised. Nausea is an unpleasant sensation of queasiness or feeling as if you are about to vomit.

Vomiting is the expulsion of the stomach contents from the mouth – most of us have experienced vomiting by the time we reach adulthood, and know we need to run for the bathroom if it happens ²⁷!

Often technically referred to as dysphoriaexperiencing little or no joy in their life, caffeine withdrawal causes a variety of negative mood states, ranging from feeling depressed, to feeling anxious or irritable. Keep in mind that these feelings should pass once the withdrawal is over, and they don’t necessarily mean you will stay feeling miserable.

Follow the advice in this post, and if your negative mood lingers once you are through with caffeine, talk to your doctor about how you are feeling. Sometimes mental health problems underlie an addiction, and only become apparent once you have quit, in which case, your doctor can provide or refer you to appropriate treatment. And sometimes a mental health problem can be triggered by drug use, including caffeine use. Again, your doctor is the best person to advise you, so don’t suffer in silence ²⁷.

This is described in various ways, but all add up to the same thing – your brain doesn’t work as efficiently when you are withdrawing from caffeine, and lab tests show that this is more than just a feeling; performance actually is poorer on mental tasks.

Remember this is a rebound effect from the stimulating and performance-enhancing effects of caffeine. Drinking more caffeine will simply perpetuate the cycle. But you don’t have to quit cold turkey – follow the instructions here for how to “taper off” caffeine ²⁷.

The sense of being light-headed or dizzy is a common withdrawal symptom of caffeine. Cutting down gradually rather than abruptly will help – see here for more information on how to do this – but don’t push yourself. Try to take things a little easier while you are cutting back on caffeine, and sit down or lie down if you feel the need.

While fainting is uncommon, pushing yourself while you are feeling lightheaded or dizzy increases the risk ²⁷.

A good way to taper down your caffeine intake is by reducing it by about 10% every two weeks. That way, you will reduce your caffeine intake enough that eventually you will be caffeine-free, but it will take several months to get there. The advantage is that you shouldn’t have very noticeable withdrawal symptoms while cutting back, and you can gradually replace your caffeinated foods and drinks for uncaffeinated or decaffeinated versions.

Start by keeping a caffeine diary, and writing down all the foods and drinks containing caffeine that you consume. Be sure to check the labels of any painkillers to see if they include caffeine, and remember that many recreational drugs are cut with caffeine.

Then gradually start to reduce your caffeine intake by 10%, continuing to keep a daily record. There are a few ways of doing this – some people reduce each caffeinated drink by 10%, and dilute it by adding 10% hot or cold water, or decaffeinated coffee or tea. Others find it easier to reduce the actual number of drinks by 10%, so if you have five cups of coffee per day, replace one cup with a half cup for the first two weeks, then by a whole cup the next two weeks, and so on.

Decaffeinated coffee has been found to actually reduce caffeine withdrawal symptoms, including cravings, fatiguea feeling of weariness, tiredness, or lack of energy. More, lack of alertness and flu-like feelings, when people going through caffeine withdrawal think they are drinking caffeinated coffee. This is known as the placeboA substance that has positive effects as a result of a patient's perception that it is beneficial rather than as a result of a causative ingredient. It is an inactive substance or preparation used as a control in an experiment or test to determine the effectiveness of a medicinal drug effect. As your withdrawal symptoms diminish, you might find it helpful to substitute an uncaffeinated drink, such as herbal tea or water, or decaffeinated coffee or tea, for each drink you remove, so you gradually develop a taste for drinks that do not contain caffeine.

If you are using the drink replacement strategy, it is easiest to work backwards from the last drink of the day – this will have the bonus effect of helping you sleep better at night ²⁷.

The symptoms of caffeine withdrawal experienced may vary in type and severity between individuals, and can include –

• tiredness,
• anxious ³,
• headache,
• irritability,
• inability to concentrate,
• drowsiness,
• insomniadifficulty in going to sleep or in getting enough sleep,
• pain in the stomach, upper body, and jointsmarijuana cigarettes More ².

Moderate caffeine use is not thought to be harmful, and may even be beneficial. Consumption of drinks like coffee or tea probably could not result in a caffeine overdose. Some ‘energy drinks’ can have very high caffeine contents, and should be used in moderation. Caffeine pills also may contain large amounts of caffeine (some contain up to 200mg of caffeine, which is like 4 cups of coffee). Check the label of energy drinks and tablets to judge how much caffeine you are taking.

Be aware that ‘legal highs’ and controlled drugs often contain caffeine. This is a problem as you do not know how much caffeine you are taking, and it could also increase the harms of some. One study of 6 ‘legal high’ products found that some contained around 90% caffeine. This means that taking one gram of the product would be like taking around 13 litres of cola, 3.75 litres of energy drink, or 12 – 15 cups of coffee ¹.

Caffeine improves some mental abilities in tired people, and many people use it to remain alert when they are tired. Caffeine is no substitute for sleep however, and not sleeping is harmful both psychologically and physically. Once the caffeine has worn off you are likely to ‘crash’ if you are very tired ¹.

Being addicted to caffeine does not usually affect people’s lives for the worse. It does however mean that you can get withdrawal effects if you don’t have caffeine, which can be unpleasant. This would be worse for those who regularly have very large amounts of caffeine (which is easier to do with energy drinks and caffeine pills). A regular caffeine habit means that you are not necessarily making yourself more energised and alert than someone who doesn’t use caffeine, rather you need caffeine to maintain normal levels of energy and alertness. Frequent headaches can be related to caffeine withdrawal ¹.