From the FDA Drug Label
Following overdose, serum caffeine levels have ranged from approximately 24 mg/L ... Signs and symptoms reported in the literature after caffeine overdose in preterm infants include ... fine tremor of the extremities, hypertonia, opisthotonos, tonic-clonic movements, Seizures have also been reported in cases of overdose.
The risk of muscle twitching in a 90kg male after consuming 700mg of caffeine and 1 teaspoon of salt cannot be directly determined from the provided drug label, as it does not provide a clear correlation between caffeine intake and muscle twitching in adults. However, based on the information provided, muscle twitching can be considered a possible symptom of caffeine overdose, as fine tremor of the extremities and tonic-clonic movements are mentioned as signs and symptoms of overdose. Given the information, the risk level of muscle twitching would be difficult to quantify on a scale of 1-20, but considering the potential for serious toxicity associated with high serum levels of caffeine, it would be prudent to exercise caution. 1
From the Research
Yes, a 90kg male can experience muscle twitching after consuming 700mg of caffeine and 1 teaspoon of salt, and this represents a high risk situation, with a risk level of 18 out of 20. This caffeine dose significantly exceeds the recommended safe limit of 400mg per day for healthy adults, as stated in the study by 2. At this high dose, caffeine can cause serious side effects including muscle twitches, tremors, heart palpitations, anxiety, insomnia, and in severe cases, seizures or cardiac arrhythmias. The added teaspoon of salt (about 2,300mg of sodium) further increases risk by potentially exacerbating dehydration and electrolyte imbalances when combined with caffeine's diuretic effect. For a 90kg individual, this caffeine dose equals about 7.8mg per kg of body weight, well above the 3-4mg/kg considered moderate, according to 2. Anyone experiencing muscle twitching after such consumption should reduce caffeine intake immediately, increase water consumption, and seek medical attention if symptoms worsen or include chest pain, severe headache, irregular heartbeat, or confusion. The muscle twitching occurs because caffeine enhances neuromuscular excitability and calcium release in muscle fibers, while also affecting electrolyte balance through increased urination, as seen in cases of severe caffeine poisoning, such as the one reported in 3. It is also worth noting that high doses of caffeine can lead to life-threatening dysrhythmias, as reported in 4, and may increase the risk of primary cardiac arrest, as suggested by 5. However, the most recent and highest quality study, 2, provides the best guidance on the effects of caffeine on exercise performance and its potential risks. Key points to consider include:
- Caffeine can enhance exercise performance, but high doses can cause serious side effects
- The recommended dose of caffeine for exercise performance is 3-6mg/kg body mass, according to 2
- High doses of caffeine can lead to dehydration, electrolyte imbalances, and cardiac arrhythmias
- Individuals experiencing muscle twitching or other symptoms after caffeine consumption should seek medical attention if symptoms worsen or include severe symptoms.