Overview
11 DESCRIPTION Methamphetamine hydrochloride, USP, chemically known as (αS)-α-Methylbenzeneethan-(N-methyl)-amine Hydrochloride, is a member of the amphetamine group of sympathomimetic amines. It has the following structural formula: Methamphetamine hydrochloride tablets, USP contain 5 mg of methamphetamine hydrochloride, USP for oral administration.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Amphetamines are non-catecholamine sympathomimetic amines with CNS stimulant activity. The exact mode of therapeutic action in the treatment of ADHD is not known. 12.2 Pharmacodynamics Amphetamines block the reuptake of norepinephrine and dopamine into the presynaptic neuron and increase the release of these monoamines into the extraneuronal space. 12.3 Pharmacokinetics Absorption Methamphetamine is absorbed from the gastrointestinal tract. Elimination Metabolism The primary site of metabolism is in the liver by aromatic hydroxylation, N-dealkylation and deamination. At least seven metabolites have been identified in the urine. The biological half-life has been reported in the range of 4 to 5 hours.
Indications
- 1 INDICATIONS AND USAGE Methamphetamine hydrochloride tablets are indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in pediatric patients 6 years of age and older. • Methamphetamine hydrochloride tablets are a central nervous system (CNS) stimulant indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in pediatric patients 6 years of age and older. ( 1 )
Common Doses
- 5 mg
- 20 mg
- 25 mg
Dosage
2 DOSAGE AND ADMINISTRATION • Administer methamphetamine hydrochloride tablets orally once daily or in two divided doses daily. Avoid administration late in the evening due to the risk of insomnia. ( 2.2 ) • Recommended starting dosage is 5 mg once or twice daily. ( 2.3 ) • Daily dosage may be increased in 5 mg increments at weekly intervals depending on clinical response. ( 2.3 ) • The recommended dosage range is 20 mg to 25 mg daily. ( 2.3 ) 2.1 Pretreatment Screening Prior to treating patients with methamphetamine hydrochloride tablets, assess: • for the presence of cardiac disease (i.e.
Black Box Warning
Methamphetamine has a high potential for abuse and misuse, which can lead to the development of a substance use disorder, including addiction. Misuse and abuse of CNS stimulants, including methamphetamine, can result in overdose and death [see Overdosage ( 10 )] , and this risk is increased with higher doses or unapproved methods of administration, such as snorting or injection. Before prescribing methamphetamine, assess each patient’s risk for abuse, misuse, and addiction.
Contraindications
- 4 CONTRAINDICATIONS Methamphetamine hydrochloride tablets are contraindicated in patients with: • known hypersensitivity to amphetamine, or other components of methamphetamine hydrochloride tablets. Hypersensitivity reactions such as angioedema and anaphylactic reactions have been reported in patients treated with other amphetamine products [see Adverse Reactions ( 6 )] . • taking monoamine oxidase inhibitors (MAOIs), or within 14 days following discontinuation of treatment with an MAOIs (including MAOIs such as linezolid or intravenous methylene blue), because of the risk of hypertensive...
Side Effects
- 6 ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: • Abuse, Misuse, and Addiction [see Boxed Warning, Warnings and Precautions ( 5.1 ), Drug Abuse and Dependence ( 9.2 , 9.3 )] • Hypersensitivity to amphetamine products or other ingredients of methamphetamine hydrochloride tablets [see Contraindications ( 4 )] • Hypertensive Crisis When Used Concomitantly with Monoamine Oxidase Inhibitors [see Contraindications ( 4 ), Drug Interactions ( 7.1 )] • Risks to Patient with Serious Cardiac Disease [see Warnings and Precautions ( 5.
Interactions
- 7 DRUG INTERACTIONS Acidifying and Alkalinizing Agents: Agents that alter GI and urinary pH can alter blood levels of amphetamine. Acidifying agents can decrease amphetamine blood levels, while alkalinizing agents can increase amphetamine blood levels. ( 7.1 ) 7.1 Drugs Having Clinically Important Interactions with Methamphetamine Hydrochloride Tablets Table 1 presents clinically important drug interactions with methamphetamine hydrochloride tablets.