Caffeine Toxicity Clinical Presentation
- Author: David Yew, MD; Chief Editor: Asim Tarabar, MD more...
If acute caffeine ingestion is suspected, patients or their family members should be questioned about their use of prescription medications, OTC drugs, and illicit drugs. Patients and family members should be queried about the use of cocaine, amphetamines, methamphetamine, phencyclidine (PCP), antidepressants, asthma medications, thyroid medications, or anticholinergics (eg, OTC allergy medications).
The patient and his or her family members or friends may be able to give a history of recent caffeine ingestion (ingestion of alertness-promoting OTC medications, caffeinated beverages, or diet medications) or a history of recent behavior compatible with such use (eg, the patient was trying to lose weight or taking stimulants to aid in working or studying). In an acute overdose, pill bottles found at the scene may provide a clue to what the patient ingested.
When ingested chronically in excessive amounts, caffeine produces a specific toxidrome (caffeinism), which consists of primarily CNS, cardiovascular, and GI hyperstimulation.
- CNS features
- Anxiety, agitation
- Tremulousness, perioral and extremity tingling (resulting from tachypnea-induced respiratory alkalosis)
- Confusion, psychosis
- Cardiovascular features
- Palpitations or racing heart rate
- Chest pain
- GI features
- Nausea and vomiting
- Abdominal pain
- Diarrhea, bowel incontinence
See the list below:
- CNS findings
- Anxiety, agitation
- Altered mental status
- Head, eyes, ears, nose, and throat findings
- The pupils are dilated but reactive to light.
- The thyroid should be examined because thyrotoxicosis may mimic caffeine toxicity.
- Cardiovascular findings
- Characteristic finding is widened pulse pressure due to positive inotropic effect as well as vasodilatory effect of caffeine.
- Sinus tachycardia, dysrhythmias (eg, premature ventricular contractions, supraventricular tachycardias [SVTs], ventricular rhythms)
- Respiratory finding - Tachypnea
- GI findings
- Abdominal cramping
- Hyperactive bowel sounds
Chronic toxicity is generally encountered in people who have ingested higher doses of caffeine-containing compounds (alone or in combination) for various reasons. Patients may be unaware that some products contain caffeine or that high doses of caffeine can be harmful. Patients may ingest caffeine-containing analgesics for headaches, OTC caffeine-containing medications for dieting, or OTC medications for improving alertness while studying or working. In addition, people may drink caffeine in beverages such as coffee, tea, soft drinks, or energy drinks (eg, Red Bull, AMP Energy Drink, Rockstar, Monster) or take caffeine in herbal preparations .
- Acute toxicity can occur after intentional or unintentional ingestion. OTC alertness-promoting medications are often implicated in intentional overdoses.
- Certain medications, such as CYP inhibitors (eg, cimetidine) and oral contraceptives, impair caffeine metabolism.
- Caffeine clearance is reduced in patients with chronic liver disease, in pregnant women, and in infants.
- Caffeine clearance is increased in smokers. With a stable amount of ingestion, serum caffeine concentrations can double in patients who stop smoking.
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|Item||Amount||Caffeine Content, mg|
|M & M Milk Chocolate Candies||47.9 g (1 bag)||7|
|Coca-Cola Classic||12 oz||35|
|Brewed black tea, generic||8 oz||45-74|
|Red Bull Regular||8.4 oz||80|
|Brewed coffee, generic||8 oz||57|
|Midol||1 Gel Cap||60|
|No Doz||1 tablet||100|
|Regular 5-Hour Energy||2 oz||138|
|Monster Energy||16 oz||160|
|Espresso, generic||1 oz||170|
|Starbucks Tall Americano||16||330|
|Ethanol and caffeine containing||-||76||131||-||0||0|
|Ethanol and caffeine only||-||2||3||-||0||0|
|Pheylnolamine and caffeine combinations (diet aid)||10||22||11||0||0||0|
|Item||No. Exposures (single)||Exposures (5)||Exposures (6-12)||Exposures (12-19)||Exposures (20)|
|Ethanol and caffeine containing||131||15||5||78||28|
|Ethanol and caffeine pnly||3||1||0||0||2|
|Pheylnolamine and caffeine combinations (diet aid)||11||5||1||1||4|