Caffeine, caffeine, caffeine! It’s everywhere and in almost everything. It’s one of the more enigmatic substances available for human consumption. On the one hand, it is considered beneficial as an additive to a number of medicinal products, while on the other, it is known to have harmful withdrawal effects and can be highly toxic. Which of these you experience depends totally upon the amount, frequency, and duration of caffeine to which you are exposed. One reference stated “Caffeine is consumed by over 80% of U.S. adults.” That means knowingly and on purpose, but more likely, the number is 100% because it’s an ingredient in so many different products.
Non-prescription pain relievers, headache medicines, cold medicines, energy drinks, coffee, tea, colas, chocolate, and prescription drugs of all sorts contain caffeine. It’s “the world’s most used drug.” It has been included in many other products and gained its reputation because of the effects it has shown. It’s ability to pass the usually-impenetrable blood-brain barrier gives it the boost in alertness, vigilance and attention, reduced time-to-exhaustion, improved reaction time, and stimulation of energy and strength people find so appealing. Caffeine improves the efficacy of pain relievers by 40% giving that extra “kick” to aspirin, Tylenol, and other analgesic combinations. In fact, it is the most common ingredient in prescription and over-the-counter (OTC) drugs and can be “one of the most effective treatments for headache.” As an additive to pain relievers, it also helps the body absorb medications more quickly providing faster relief.
“Coffee is the predominant source of caffeine ingested by adults,” making it the “most consumed psychoactive agent in the world.” Coffee gets us started in the morning, keeps us alert and on target during the work day, and helps us cope with the stresses of family and finances. Other “players” compete for the authority to stimulate the human psyche. Teas, chocolate, cola drinks, and the abominable “energy drinks” all contain various amounts of caffeine that scramble to reach the desired effect. We learn through trial and error which of the options suits each of us the best.
Caffeine is in a class of drugs called methylxanthines. Other drugs in this class are theophylline, used for asthma, and theobromine, for cognitive stimulation. Caffeine is absorbed into the bloodstream within 45 minutes of ingestion and stays around 4-5 hours, perfect for a “quick picker-upper.” It has antioxidant, anti-inflammatory, and anti-natural cell death properties, as well.
A 6-ounce cup of coffee contains 75-100mg of caffeine (13-17mg/oz). No one drinks just 6 oz of coffee so a full styrofoam cup will have 150-200mg. Sixteen ounces of tea contains 60-100mg of caffeine (10-17mg/oz), or roughly the same amount as coffee. An ounce of chocolate contains 10mg of caffeine so in a standard 1.55 ounce Hershey bar there is roughly 15mg of caffeine. Chocolate milk, chocolate milkshakes, hot chocolate, candy, brownies, ice cream, cake, cola, and other sodas are caffeinated, as well. Even “de-caffeinated” beverages contain small amounts of caffeine.
Normal caffeine use, like a morning cup of coffee or iced tea with dinner, rarely causes caffeine withdrawal symptoms. A low dose of caffeine is 40 mg, a moderate dose is 200-300mg, and a large dose is 500mg or more (roughly 5 cups of coffee). Excess caffeine ingested daily over weeks to months will cause withdrawal symptoms with “sudden cessation.” Withdrawal symptoms include headache, weakness/loss of strength, anxiety/decreased attention, depressed mood, and flu-like symptoms.
“Caffeine abuse and dependence are becoming more common and can lead to caffeine intoxication which puts patients at risk for premature and unnatural death.” Caffeine becomes “toxic” when a dose of 1200mg is exceeded and is “fatal” at a dose of 10-14 grams (10,000-14,000mg). “Caffeine overdose is rare” because one would have to “drink 70-100 cups of coffee” to reach that end.
Energy drinks are potentially a big problem because young people, the majority of users, take them without regard for safety, drink them in combination with other stimulants or alcohol, and take caffeine in combination with strenuous activity. That’s a recipe for trouble. Many years before energy drinks existed, a patient, who was a competitive weight lifter, always took an unknown amount of caffeine tablets before a competition, to boost his strength and energy so he could lift enough to beat the other contestants. One time during competition he passed out and had to be taken to the ER. The caffeine-strenuous lifting combination was too much and his vascular system collapsed causing him to lose consciousness. He later told me the episode DID NOT cause him to alter his routine, however, and he continued using caffeine. He was very lucky later reactions were not worse.
A common caffeine-related condition is “analgesic rebound headache.” Headache sufferers are heavy users of pain relievers containing caffeine. Caffeine helps the pain reliever to work better and faster so patients take Excedrin, Anacin, Vanquish, Vivarin, Midol, or Goody’s tablets or powder as often as they need to. The headache gets better but “rebounds” when the caffeine effect wears off. This leads to a vicious cycle of HA, analgesic, HA, analgesic, etc. Rebound headaches stop only if the patient abstains from all caffeine-containing drugs and pain relievers. It’s a hard cycle to disrupt, but can be done with “physician supervision.”
Caffeine has less consistent effect on memory, high-order executive functioning, such as decision-making, and judgement. In the cardiovascular realm, caffeine increases both heart rate and pumping capacity. It has been shown to be additive and beneficial for the treatment of Alzheimer’s disease, Parkinson’s disease, and ALS (Amyotrophic Lateral Sclerosis) probably because of it central nervous system stimulant effects.
I remember a couple of times as a freshman in college (1962-1963) I was so drowsy from studying and sleep deprivation I took NoDoz. Today’s NoDoz contains 200mg of caffeine. The dose 60 years ago may have been different, but I know I actually felt worse after I took it. I was awake, but my learning capability was blunted. I was “too awake.” It did not make me sharper mentally, but I had a “drugged” feeling. After that experience, I never took NoDoz again.
For many years I drank coffee every morning. It was part of my morning-hospital-rounds and nursing-home-visit routine. It helped me keep up a pace to prevent falling behind time-wise. But it made me feel jittery, flushed, hot, and sweaty so one day I abruptly decided enough was enough. I quit cold turkey. Fortunately, I did not experience withdrawal. In the last 20-25 years I have had fewer than 5 cups of coffee. I still drink tea (lots of it), but it has never affected me like coffee. Diet soda has some caffeine affect, but because I drink Coke less than once a week, I have no issue with it.
For reference and your interest, below I have listed the amount of caffeine in common, everyday sources of caffeine we all consume. I hope your source is mentioned.
5-Hour Energy drinks—70mg (of caffeine)/ounce ***BINGO!! WOW!!
NoDoz tablets—200mg/tablet
Excedrin Migraine—65mg/tablet
Anacin Maximum Strength—32mg/tablet
Black coffee—80-100mg/8ounces
Zest Energy Tea—30-150mg/8 ounces
Diet Coke—41.3 mg/12 ounces
Regular Coke—33.9mg/12 ounces
Diet Pepsi—36.7mg/12 ounces
Regular Pepsi—38.9mg/12 oz
Diet Dr. Pepper—44.1mg/12 oz
Regular Dr. Pepper—42.6mg/12 oz
Mt. Dew—54.8mg/12 oz
Caffeine is a “drug” we should all respect. By that I mean we need to be wary of its effects, both positive and negative, and not think of it as harmless. It has the capability of causing serious problems so if we’re not careful, however subtly, toxicity can occur. Anything in “moderation” is most likely safe, but caffeine use seems to fall into the excessive category more often than not.
References: https://speakingofwomenshealth.com/health-library/caffeine-and-headache
Wickham KA, Spriet LL. Administration of caffeine in alternate forms. Review: Sports Med 2018 Mar;48(suppl1):79-91.
Spriano P. Ready for a jolt? Caffeine brings benefits and Risks. Medscape Medical News 2024 October 11.
McClellan TM, Caldwell JA, Lieberman HR. A review of caffeine’s effects on cognitive, physical, and occupational performance. Neuroscience and Behavioral Reviews 71 2016:294-312.
Cappelletti S, Piacentino D, Sani G, Aromatario M. Caffeine: cognitive and physical performance enhancer or psychoactive drug? Review: Curr Neuropharmacol.2015 Jan;13(1):71-88.
Kolahdouzan M, Hamadeh MJ.The neurodegenerative effects of caffeine in neurodegenerative diseases. CNS Neurosci Ther 2017 April;23(4):272-290.
