Comparative Pharmacology
Head-to-head clinical analysis: CONCERTA versus METHAMPEX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CONCERTA versus METHAMPEX.
CONCERTA vs METHAMPEX
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Methylphenidate is a central nervous system (CNS) stimulant. It blocks the reuptake of norepinephrine and dopamine into presynaptic neurons, increasing their levels in the synaptic cleft. It also acts as a dopamine agonist by stimulating the release of dopamine from storage sites.
Methamphetamine is a sympathomimetic amine that increases synaptic concentrations of dopamine, norepinephrine, and serotonin by promoting their release from presynaptic terminals and inhibiting their reuptake. It also inhibits monoamine oxidase, reducing neurotransmitter catabolism.
18-72 mg orally once daily in the morning, starting at 18-36 mg/day and titrating in 18 mg increments weekly; maximum 72 mg/day.
150 mg orally twice daily for 12 weeks; alternative: 90 mg orally twice daily if tolerability issues.
None Documented
None Documented
Terminal elimination half-life of methylphenidate from CONCERTA is approximately 3.5 hours (range 2.5-5.5 hours) in adults; in children, mean half-life is 3-4 hours. The extended-release formulation provides a prolonged clinical effect due to the OROS delivery system, not prolonged half-life.
Terminal elimination half-life is approximately 9-14 hours in adults with normal renal function (mean ~12 hours). In children, half-life is shorter (~8-10 hours). Context: Steady-state is achieved within 2-3 days. Half-life may be prolonged in patients with renal impairment (up to 20-30 hours) or alkaline urine (up to 30 hours).
Primarily renal (77%-87% as unchanged drug and metabolites); metabolic elimination accounts for 13%-23%, with minor biliary excretion (<2%).
Primarily renal excretion (≥90% as unchanged drug and metabolites); approximately 70-80% as unchanged amphetamine, 10-15% as deaminated metabolites (hippuric acid, benzoic acid). Biliary/fecal excretion is negligible (<5%). Renal clearance is pH-dependent; acidic urine increases elimination. In overdose or renal impairment, elimination half-life may prolong.
Category C
Category C
CNS Stimulant
CNS Stimulant