Caffeine adverse effects

True. Caffeine is a mild stimulant that in moderate dosage does little harm and provides a lift . When taken in excess it can have an adverse effect on heart rate. 

Caffeine did not have adverse effect in subjects with adequate calcium intakes near or above 800 mg/d, although daily caffeine intake a2-3 servings of brewed coffee may accelerate bone loss from the spine and total body in women with a low calcium intake. 

Before discussing the animal data it is important to note that caffeine is metabolized differently in experimental animals than it is in humans. This is particularly so in the rat, which is the most common experimental model used. Therefore results in animals, either positive or negative, cannot be directly applied to humans. However, since caffeine itself and some of its metabolites are present in both the animal experiments and during human exposure, an adverse effect of caffeine in an animal model should be verified or excluded in the human. 

The adverse effects of caffeine are a common experience to most caffeine consumers. Too much caffeine results in uncomfortable to adverse central nervous system effects, or neurotoxicity. The effects include restlessness, tension, and mild tremor or the jitters and may progress to feelings of anxiety and even fear. Regular caffeine users soon learn how to manage their caffeine consumption to maintain blood caffeine at a desirable level that produces mild stimulation without the uncomfortable neurotoxic effects. Fortunately, the half-life of caffeine is short, so that any undesirable effects soon decline. Many people also experience insomnia from caffeine consumption. Caffeine s effect on sleep varies from individual to individual. Some people can consume caffeine late in the evening and sleep well, but for other people consumption of caffeine late in the day affects sleep. It is important to understand your own individual response to caffeine. 

The creatures of the world, both animals and plants, produce a wide range of biologically active substances. Biologically active substances produced by animals or plants that cause an adverse effect are called toxins. Toxins refers only to toxic agents produced by animals and plants, not toxic substances such a lead or pesticides. The classification of a substance as a toxin tends to be in the eye of the beholder. Is caffeine, a naturally occurring agent in many plants, a toxin or just a pharmacologically active compound or both ... 

Pharmacology The study of the beneficial and adverse effects of drugs Benefits of aspirin or caffeine... 

Clozapine is principally metabolized to N -desmethylclozapine (norclozapine). It is also metabolized to and n-oxide, other hydroxyl metabolites, and a protein-reactive metabolite. The n-oxide can be converted back to clozapine. The enzyme responsible for the metabolism of clozapine to norclozapine is the cytochrome P450 1A2 enzyme (325). This is consistent with a study showing that caffeine, a marker for 1A2, is cleared in relationship to the conversion of clozapine to norclozapine ( 326). Discontinuation of coffee intake can decrease the clozapine plasma levels by more than 50%, and increasing caffeine intake can produce a reemergence of the side effects (e.g., drowsiness, excess salivation). Additionally, smoking, which induces 1A2, lowers clozapine plasma levels. Fluvoxamine, an inhibitor of 1A2, dramatically increases plasma levels, and on occasion, adverse effects are seen ( 327). This phenomenon can lead to clozapine intoxication in patients on high doses of fluvoxamine. 

Most follow-ups to earlier studies warning of the adverse effects of caffeine have failed to duplicate the initial findings, especially for the moderate use of caffeine. However, at the start of the new millennium, youth culture thrived on the excessive use of caffeine. New drinks were purposely formulated to contain large amounts of the mild stimulant, increasing the risk of possible adverse effects. 

When studies in the 1980s raised concern about possible adverse effects, including miscarriage, birth defects, and infertility, doctors advised pregnant women to cut out caffeine entirely. Most of these studies have not been confirmed. Certainly, the amounts of caffeine... 

The American Cancer Society states that there does not seem to be any relationship between caffeine and cancer. However, other adverse effects for women remain a concern, such as the possibility that large amounts of caffeine could contribute to osteoporosis (thinned and fragile bones), particularly in elderly women. As caffeine is a diuretic, which increases loss of fluids and electrolytes in the urine, it could rob the body of calcium. Nevertheless, a study published in 2001 concluded that the net effect of carbonated sodas on the body s calcium is negligible, and that the loss of calcium in urine due to carbonated drinks is too small to affect calcium balance. 

H. Tanaka, K. Nakazawa and M. Arima, Adverse effect of maternal caffeine ingestion on fetal cerebrum in rat, Brain Develop., 5 (1983) 397-406. 

Adverse effects Moderate doses of caffeine cause insomnia, anxiety, and agitation. A high dosage is required to show toxicity, which is manifested by emesis and convulsions. The lethal dose is about 10 g for caffeine (about 100 cups of coffee), which induces cardiac arrhythmias death from caffeine is thus highly unlikely. Lethargy, irritability, and headache occur in users who have routinely consumed more than 600 mg of caffeine per day (roughly 6 cups of coffee/day) and then suddenly stop. 

As can be seen from Table I a substantial number of alkaloids display significant insect toxicity, including nicotine, pipeline, lupine alkaloids, caffeine, gramine, strychnine, berberine, ephedrine, and steroidal alkaloids. Only the specialists can tolerate the respective alkaloids. The tobacco homworm (Manduca sexto), for example, can grow on a diet with more than 1% nicotine without any adverse effects. Most of the nicotine is either degraded or directly eliminated via the Malpighian tubules and in feces 182). Because nicotine binds to the acetylcholine (ACH) receptor, it is likely that in Manduca this receptor has been modified in such a way that ACH can still bind, but not nicotine (so-called target site modification). 

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