Adderall XR and Caffeine Interaction: What You Need to Know Before Your Morning Coffee

Does the Adderall XR label list caffeine?

No. The prescribing information for Adderall XR carries a table of drugs with clinically important interactions with amphetamines. It names monoamine oxidase inhibitors, serotonergic drugs such as SSRIs and SNRIs, CYP2D6 inhibitors, alkalinizing agents such as antacids and sodium bicarbonate, acidifying agents such as ascorbic acid, tricyclic antidepressants and proton pump inhibitors [1]. Caffeine is not among them.

Alkalinizing agents raise amphetamine blood levels and potentiate its action, and the label says coadministration with gastrointestinal or urinary alkalinizing agents should be avoided. Acidifying agents lower amphetamine blood levels and its efficacy [1]. Caffeine is not listed in either category [1].

How do amphetamine and caffeine act?

Amphetamines are thought to block reuptake of norepinephrine and dopamine into the presynaptic neuron and to increase release of both into the space outside it; how that produces the therapeutic effect in ADHD is not known. Caffeine is an adenosine receptor antagonist, and a key part of its stimulant effect is its ability to release the brake that adenosine puts on dopaminergic neurotransmission [4].

Adderall XR can raise blood pressure and heart rate [1], while too much caffeine in children and teens can cause increased heart rate, palpitations, high blood pressure, anxiety and sleep problems [2]. The size of any combined effect of the two is not established.

What does Adderall XR do to blood pressure and heart rate?

The label states that CNS stimulants may raise blood pressure by a mean of about 2 to 4 mmHg and heart rate by about 3 to 6 bpm, with larger rises in some patients, and says to monitor all Adderall XR-treated patients for hypertension and tachycardia [1]. It also says to avoid Adderall XR in people with structural cardiac abnormalities, cardiomyopathy, serious cardiac arrhythmia, coronary artery disease or other serious cardiac disease, because sudden death has been reported with CNS stimulants at recommended ADHD doses in that group [1].

In the 4-week adult Adderall XR study the label reports (191 adults on active drug at 20 to 60 mg, 64 on placebo), common reactions were dry mouth in 35% versus 5%, loss of appetite 33% versus 3%, insomnia 27% versus 13%, headache 26% versus 13%, anxiety 8% versus 5% and tachycardia 6% versus 3% [1].

How much caffeine, and what counts?

The FDA cites 400 mg a day as an amount not generally associated with negative effects in most adults, roughly two to three 12-fluid-ounce cups of coffee, and notes wide variation in sensitivity and in how fast people clear caffeine, with some medications and conditions raising sensitivity [2]. Per 12 fluid ounces, typical caffeine is 113 to 247 mg for regular brewed coffee, 71 mg for black tea, 37 mg for green tea, 23 to 83 mg for a caffeinated soft drink and 41 to 246 mg for an energy drink [2]. Decaf is not caffeine-free, at typically 2 to 15 mg per 8-fluid-ounce cup, and caffeine added to a product is handled by the body the same way as caffeine that occurs naturally [2].

Caffeine's half-life averaged about 3.4 hours in healthy men and non-pregnant women, with a range of 2 to 5 hours across 25 people [3]. In another study, non-smoking women not taking oral contraceptives had a mean half-life of 5.37 hours [5].

Timing: the capsule and the cup

Adderall XR is an extended-release capsule taken once daily on awakening; the label says afternoon doses should be avoided because of the potential for insomnia [1]. Blood levels peak about 7 hours after a dose [1].

Caffeine also affects sleep. In a randomized trial that monitored sleep at home, 400 mg of caffeine taken at bedtime, three hours before bedtime, or six hours before bedtime each significantly disturbed sleep compared with placebo [7].

What about energy drinks and teenagers?

Adderall XR is approved for ADHD in adults and children aged 6 and older and is not recommended under 6 [1]. The FDA, citing the American Academy of Pediatrics, says medical experts advise against energy drinks for children and teens because of their sugar and caffeine levels. It adds that too much caffeine in this age group can cause increased heart rate, palpitations, high blood pressure, anxiety, sleep problems and digestive problems [2].

Energy drinks range from 41 to 246 mg of caffeine per 12 fluid ounces on the FDA's list [2], and a review of energy drink use in young people found that they frequently contain high and unregulated amounts of caffeine and that many of their other ingredients are understudied [8]. The Adderall XR label also records weight loss and slowed growth in children on stimulants and says to monitor height and weight during treatment [1].

What about pregnancy?

The Adderall XR label says the drug may cause fetal harm [1]. For caffeine, ACOG's committee opinion on moderate consumption states that less than 200 mg a day does not appear to be a major contributor to miscarriage or preterm birth, and that the relationship with growth restriction remains undetermined [9].