Mixed amphetamine salts: Difference between revisions
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| starting_dose = 2.5 mg IR, 5 mg XR, or 12.5mg Mydayis | | starting_dose = 2.5 mg IR, 5 mg XR, or 12.5mg Mydayis | ||
| preparations = IR tabs 5, 7.5, 10, 12.5, 15, 20, 30 mg; XR caps 5, 10, 15, 20, 25, 30 mg; Mydayis caps 12.5, 25, 37.5, 50 mg | | preparations = IR tabs 5, 7.5, 10, 12.5, 15, 20, 30 mg; XR caps 5, 10, 15, 20, 25, 30 mg; Mydayis caps 12.5, 25, 37.5, 50 mg | ||
| fda_max = | | fda_max = XR = 40 or 60 mg/d; IR = 40 or 60 mg/d<ref name="carlat">S0</ref> | ||
| routes = Oral | | routes = Oral | ||
| onset = IR: 30–60 min; XR: 1–2 h to peak effect | | onset = IR: 30–60 min; XR: 1–2 h to peak effect | ||
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* <effect ref="withdrawal" author="MDElliottMD">Low motivation, low mood, hypersomnia, increased appetite on abrupt discontinuation.</effect> | * <effect ref="withdrawal" author="MDElliottMD">Low motivation, low mood, hypersomnia, increased appetite on abrupt discontinuation.</effect> | ||
* <effect ref="urinary-retention" author="MDElliottMD">Difficult/slow urination</effect> | * <effect ref="urinary-retention" author="MDElliottMD">Difficult/slow urination</effect> | ||
<effect ref="focus-intensification"/> | |||
<effect ref="appetite-suppression"/> | |||
<effect ref="alertness"/> | |||
<effect ref="executive-functioning"/> | |||
| pk_absorption = Excellent oral bioavailability — sources report ">75%" to "~90%". Food does not significantly affect total absorption but can delay peak concentration. | | pk_absorption = Excellent oral bioavailability — sources report ">75%" to "~90%". Food does not significantly affect total absorption but can delay peak concentration. | ||
| pk_distribution = Volume of distribution ~4 L/kg; plasma protein binding less than 20%. Crosses the blood–brain barrier and placenta. | | pk_distribution = Volume of distribution ~4 L/kg; plasma protein binding less than 20%. Crosses the blood–brain barrier and placenta. | ||
| pk_metabolism = Amphetamine is oxidized to 4-hydroxyamphetamine, α-hydroxyamphetamine, or norephedrine. Norephedrine and 4-hydroxyamphetamine are active metabolites and are further metabolized to 4-hydroxy-norephedrine. Deamination of α-hydroxyamphetamine yields phenylacetone, which is metabolized to benzoic acid and conjugated to its glucuronide and hippuric acid. '''CYP2D6''' is crucial for amphetamine metabolism; genetic polymorphism causes significant inter-patient variability in clearance. Amphetamine itself inhibits monoamine oxidase (MAO), and both CYP1A2 and CYP3A4 contribute to its metabolism.<ref> | | pk_metabolism = Amphetamine is oxidized to 4-hydroxyamphetamine, α-hydroxyamphetamine, or norephedrine. Norephedrine and 4-hydroxyamphetamine are active metabolites and are further metabolized to 4-hydroxy-norephedrine. Deamination of α-hydroxyamphetamine yields phenylacetone, which is metabolized to benzoic acid and conjugated to its glucuronide and hippuric acid. '''CYP2D6''' is crucial for amphetamine metabolism; genetic polymorphism causes significant inter-patient variability in clearance. Amphetamine itself inhibits monoamine oxidase (MAO), and both CYP1A2 and CYP3A4 contribute to its metabolism.<ref>S1</ref> | ||
| pk_elimination = Primarily renal — ~30–40% recovered as unchanged amphetamine, the rest as metabolites. Due to its pK<sub>a</sub> of 9.9, urinary elimination is highly pH-dependent: alkaline urine reduces ionization and decreases renal clearance, while acidic urine and high flow rates accelerate clearance via active tubular secretion. '''Half-life:''' D-enantiomer 9 h (children 6–12 y), 11 h (adolescents 13–17 y), 10 h (adults); L-enantiomer 11 h, 13–14 h, 13 h respectively. | | pk_elimination = Primarily renal — ~30–40% recovered as unchanged amphetamine, the rest as metabolites. Due to its pK<sub>a</sub> of 9.9, urinary elimination is highly pH-dependent: alkaline urine reduces ionization and decreases renal clearance, while acidic urine and high flow rates accelerate clearance via active tubular secretion. '''Half-life:''' D-enantiomer 9 h (children 6–12 y), 11 h (adolescents 13–17 y), 10 h (adults); L-enantiomer 11 h, 13–14 h, 13 h respectively. | ||
| pharmacodynamics = Amphetamine purportedly works via several converging mechanisms at monoaminergic terminals: | | pharmacodynamics = Amphetamine purportedly works via several converging mechanisms at monoaminergic terminals: | ||
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| monitoring = * Baseline: cardiovascular history, weight/height, mental health history (especially for psychosis/bipolar/substance use risk), (optional) blood pressure, (optional) heart rate, | | monitoring = * Baseline: cardiovascular history, weight/height, mental health history (especially for psychosis/bipolar/substance use risk), (optional) blood pressure, (optional) heart rate, | ||
* At each visit: efficacy, side effects, general well-being | * At each visit: efficacy, side effects, general well-being | ||
* Periodically reassess continued need; consider | * Periodically reassess continued need; consider medicine holidays to assess ongoing benefit | ||
* Sleep quality (insomnia is dose-limiting) | * Sleep quality (insomnia is dose-limiting) | ||
| counseling = * Take first thing in the morning to minimize insomnia; avoid (late) afternoon dosing. | | counseling = * Take first thing in the morning to minimize insomnia; avoid (late) afternoon dosing. | ||
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| references = | | references = | ||
}} | }} | ||
[[Category:Stimulants & Wake-Promoting Agents]] | |||
[[Category:Amphetamines]] | |||