- What are oral caffeine tablets, and how do they work (mechanism of action)?
- What are the uses for oral caffeine tablets?
- What are the side effects of oral caffeine tablets?
- What is the dosage for oral caffeine tablets?
- Which drugs or supplements interact with oral caffeine tablets?
- Are oral caffeine tablets safe to take if I'm pregnant or breastfeeding?
- What else should I know about oral caffeine tablets?
What are oral caffeine tablets, and how do they work (mechanism of action)?
Caffeine acts as a stimulant of the nervous system by inhibiting the enzyme phosphodiesterase, just like theophylline and aminophylline. Inhibiting this enzyme leads to increased formation of the proteins which causes release of stimulating chemical signals known as neurotransmitters. These neurotransmitters bind to various sites in the body, including the brain, heart, and muscles to cause a stimulant effect.
What brand names are available for oral caffeine tablets?
Enerjets, No Doz, Vivarin
Are oral caffeine tablets available as a generic drug?
GENERIC AVAILABLE: Yes
Do I need a prescription for oral caffeine tablets?
No
What are the uses for oral caffeine tablets?
What are the side effects of oral caffeine tablets?
Side effects associated with caffeine supplements include irregular heartbeat, chest pain, flushing, palpitations, rapid heartbeat, agitation, dizziness, hallucinations, headache, insomnia, irritability, psychosis, restlessness, rash, increased pressure in the eye, and frequent urination.
What is the dosage for oral caffeine tablets?
100 to 200 mg every 3 to 4 hours as needed no later than 6 hours before bedtime.

SLIDESHOW
Sleep Disorders: Foods That Help Sleep or Keep You Awake See SlideshowWhich drugs or supplements interact with oral caffeine tablets?
Combining caffeine with other stimulating agents, such as methylphenidate (Ritalin, Ritalin SR, Ritalin LA, Concerta, Methylin, Methylin ER, Metadate CD, Metadate ER), should be done with caution. This combination may cause increased side effects including rapid heartbeat, high blood pressure, hallucinations, tremor, and anxiety. Other dietary sources of caffeine, such as tea, add to the effect. Caffeine should be used with caution with adenosine, as the effects of adenosine may be diminished. Linezolid, phenelzine, selegiline, and tranylcypromine combined with caffeine increases the risk of high blood pressure. Consider alternatives when combining caffeine and vemurafenib and Stiripentol as caffeine concentrations may be increased.
Are oral caffeine tablets safe to take if I'm pregnant or breastfeeding?
Category C; usual dietary exposure to caffeine is unlikely to cause congenital malformations, however studies show conflicting results about adverse events. Concentrations in the mother are similar to those found in the fetus. Daily intake should be no more than 200 mg.
Caffeine enters the breast milk, and, therefore should be used cautiously by nursing mothers.
Summary
Caffeine (Enerjets, No Doz, Vivarin) is an over-the-counter (OTC) stimulant used to revive mental alertness and wakefulness when feeling fatigue and drowsiness or experiencing caffeine withdrawal. Review side effects, drug interactions, dosage, and storage information prior to taking this drug.
Related Disease Conditions
-
Migraine Headache
Migraine headache is a type of headache associated with a sensitivity to light, smells, or sounds, eye pain, severe pounding on one side of the head, and sometimes nausea and vomiting. The exact cause of migraine headaches is not known. Triggers for migraine headaches include certain foods, stress, hormonal changes, strong stimuli (loud noises), and oversleeping. Treatment guidelines for migraines include medicine, pain management, diet changes, avoiding foods that trigger migraines, staying hydrated, getting adequate sleep, and exercising regularly. Prevention of migraine triggers include getting regular exercise, drinking water daily, reducing stress, and avoiding trigger foods.
-
Fatigue and Exhaustion
Fatigue can be described in various ways. Sometimes fatigue is described as feeling a lack of energy and motivation (both mental and physical). The causes of fatigue are generally related to a variety of conditions or diseases, for example, anemia, mono, medications, sleep problems, cancer, anxiety, heart disease, and drug abuse.Treatment of fatigue is generally directed toward the condition or disease that is causing the fatigue.
-
Paroxysmal Supraventricular Tachycardia (PSVT)
Paroxysmal supraventricular tachycardia (PSVT) is an abnormal conduction of electricity in particular areas of the heart. PSVT was referred to at one time as paroxysmal atrial tachycardia or PAT, however, the term PAT is reserved for as specific heart condition. Symptoms of PSVT include weakness, shortness of breath, chest pressure, lightheadedness, and palpitations. PSVT is treated with medications or procedures that return the heart to its normal electrical pattern.
Treatment & Diagnosis
Prevention & Wellness

Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.