Comparative Pharmacology
Head-to-head clinical analysis: ADDERALL XR 20 versus METADATE ER.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ADDERALL XR 20 versus METADATE ER.
ADDERALL XR 20 vs METADATE ER
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Adderall XR 20 is a combination of amphetamine enantiomers (dextroamphetamine and levoamphetamine). It increases synaptic levels of dopamine and norepinephrine by inhibiting their reuptake and promoting their release from presynaptic terminals.
Methylphenidate is a central nervous system stimulant that inhibits the reuptake of dopamine and norepinephrine into presynaptic neurons, increasing their concentrations in the synaptic cleft. It also acts as a weak agonist at serotonin receptors.
20 mg orally once daily in the morning.
Initial: 10-20 mg orally once daily in the morning. May increase by 10-20 mg at weekly intervals. Maximum: 60 mg/day.
None Documented
None Documented
Approximately 10-13 hours for d-amphetamine and 13-15 hours for l-amphetamine in adults; in children, 9-11 hours. The extended-release formulation provides a prolonged therapeutic effect masking shorter elimination.
Terminal elimination half-life: 3-6 hours (mean 4.5 hours) for methylphenidate; clinical context: requires multiple daily dosing or extended-release formulation.
Approximately 90% of an oral dose is excreted renally, with 30% as unchanged amphetamine and the remainder as metabolites (including hippuric acid, benzoic acid, and hydroxylated derivatives). Fecal/biliary excretion accounts for <10%.
Renal (80% as metabolites, <1% unchanged); fecal (10-20%) via biliary elimination.
Category C
Category C
CNS Stimulant
CNS Stimulant