Types of Caffeine Pills

The John Hopkins Bayview Medical Center describes caffeine as a common mood-altering drug consumed by most American adults and children. This is because it is present in varying amounts in many beverages like coffee, tea and soft drinks, as well as in energy bars, and foods containing chocolate such as candies, puddings and cookies. Apart from food, caffeine is also added to many over-the-counter and prescription drugs. Irrespective of whether it is in food or in pills, caffeine acts as a stimulant of the central nervous system, which can affect your mood and behavior.

CNS Stimulant and Weight Loss Pills

Caffeine pills may be used under medical supervision for hypersomnia -- drowsiness that can cause you to feel sleepy in the daytime -- or if want to stay awake. The caffeine increases alertness and wakefulness as it acts a central nervous system stimulant. Caffeine, present in some dietary supplements and weight loss pills, may help reduce weight by decreasing hunger pangs; causing increased energy, which in turn can lead to burning more calories; and increasing water loss. However, Katherine Zeratsky, registered dietitian writing on MayoClinic.com, cautions that adverse effects like nervousness, insomnia, nausea and high blood pressure can arise by high intake of caffeine.

Athletic Performance Pills

Caffeine pills may help improve athletic performance by increasing stamina for working out. According to Drugs.com, caffeine may work either by using fat instead of glycogen as a source of energy instead of glycogen, or by stimulating the central nervous system by decreasing the feeling of tiredness. Athletes should use caffeine with caution as it can mask the need for rest and increase the need to urinate. Additionally, you should be aware of the amount of caffeine you are taking before an athletic event, as the International Olympic Committee and other sports institutions consider it a performance-enhancing drug.

Analgesic Pills

Some of the over-the-counter drugs that contain caffeine include analgesics that work to reduce cold symptoms, fever, hangover, headaches, migraines, muscle pain, premenstrual syndrome, osteoarthritis and rheumatoid arthritis and sinusitis. The caffeine content in a single dose, generally comprising of two tablets, may range anywhere from 64 to 130 milligrams, according to John Hopkins Bayview Medical Center.

Effects of Caffeine

In moderate amounts of 100 to 200 milligrams, caffeine exerts a positive effect by increasing alertness and energy levels. It also improves focus and promotes a feeling of well-being. However, a high intake of caffeine can increase your heart rate, cause an irregular heart rhythm and raise blood pressure. It can also cause headaches, nervousness, dizziness, anxiety, irritability, insomnia and frequent urination that can lead to dehydration. An excessive amount of caffeine intake is possible, which can be dangerous and even fatal, according to the FDA.