Amphetamine exerts its behavioral effects by altering the use of monoamines as neuronal signals in the brain, primarily in catecholamine neurons in the reward and executive function pathways of the brain. Amphetamine may also decrease the effects of antihypertensives and antipsychotics due to its effects on blood pressure and dopamine respectively. In particular, amphetamine may decrease the effects of sedatives and depressants and increase the effects of stimulants and antidepressants. Amphetamine also interacts with MAOIs, particularly monoamine oxidase A inhibitors, since both MAOIs and amphetamine increase plasma catecholamines (i.e., norepinephrine and dopamine); therefore, concurrent use of both is dangerous. Inhibitors of enzymes that metabolize amphetamine (e.g., CYP2D6 and FMO3) will prolong its elimination half-life, meaning that its effects will last longer. Many types of substances are known to interact with amphetamine, resulting in altered drug action or metabolism of amphetamine, the interacting substance, or both.
Drug Interactions
Call your doctor for medical advice about side effects. Some side effects may occur that Amphetamine Drug Profile usually do not need medical attention. Although not all of these side effects may occur, if they do occur they may need medical attention.
- The amount of medicine that you take depends on the strength of the medicine.
- However, the quality of evidence for these findings is low and is consequently reflected in the AASM’s conditional recommendation for dextroamphetamine as a treatment option for narcolepsy.
- Addiction is a serious risk with heavy recreational amphetamine use, but is unlikely to occur from long-term medical use at therapeutic doses; in fact, lifetime stimulant therapy for ADHD that begins during childhood reduces the risk of developing substance use disorders as an adult.
Among European Union (EU) member states in 2018,update 11.9 million adults of ages 15–64 have used amphetamine or methamphetamine at least once in their lives and 1.7 million have used either in the last year. In spite of strict government controls, amphetamine has been used legally or illicitly by people from a variety of backgrounds, including authors, musicians, mathematicians, and athletes. For example, during the early 1970s in the United States, amphetamine became a schedule II controlled substance under the Controlled Substances Act. Benzedrine sulfate was introduced 3 years later and was used to treat a wide variety of medical conditions, including narcolepsy, obesity, low blood pressure, low libido, and chronic pain, among others.
Amphetamine is a weak base with a pKa of 9.9; consequently, when the pH is basic, more of the drug is in its lipid soluble free base form, and more is absorbed through the lipid-rich cell membranes of the gut epithelium. The oral bioavailability of amphetamine varies with gastrointestinal pH; it is well absorbed from the gut, and bioavailability is typically 90%. Acute amphetamine administration can also increase adrenocorticotropic hormone and corticosteroid levels in blood plasma by stimulating the hypothalamic–pituitary–adrenal axis. Amphetamine also induces the selective release of histamine from mast cells and efflux from histaminergic neurons through VMAT2.
Amphetamine (oral route)
- Make sure your healthcare provider knows about every medication, herbal remedy or supplement you take.
- In addition to presynaptic actions that regulate DAT, TAAR1 activation exerts a somatodendritic inhibitory influence on dopamine output by reducing the firing rate of midbrain dopamine neurons via G protein-coupled inwardly-rectifying potassium channels, an effect that can attenuate amphetamine’s psychostimulant response.
- If you miss a dose of this medicine, take it as soon as possible.
- Depending on whether a person is abusing amphetamines in pill, powder, crystal, or liquid forms will dictate how they take the drug.
Nonmedical amphetamine use is common with amphetamine, dextroamphetamine and methamphetamine. There are several prescription amphetamine drugs, and even more brand names. Some countries, such as South Korea and Japan, have banned substituted amphetamines even for medical use.
Amphetamine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
Keep all medication out of sight and reach of children as many containers are not child-resistant. Store the orally disintegrating tablet blister packages in the provided plastic sleeves. Keep this medication in the container it came in, tightly closed, and out of reach of children.
The Cochrane reviewsnote 7 on the treatment of ADHD in children, adolescents, and adults with pharmaceutical amphetamines stated that short-term studies have demonstrated that these drugs decrease the severity of symptoms, but they have higher discontinuation rates than non-stimulant medications due to their adverse side effects. Zinc supplementation may reduce the minimum effective dose of amphetamine when it is used for the treatment of ADHD.note 17 Norepinephrine reuptake inhibitors (NRIs) like atomoxetine prevent norepinephrine release induced by amphetamines and have been found to reduce the stimulant, euphoriant, and sympathomimetic effects of dextroamphetamine in humans. Long-term amphetamine exposure at sufficiently high doses in some animal species is known to produce abnormal dopamine system development or nerve damage, but, in humans with ADHD, long-term use of pharmaceutical amphetamines at therapeutic doses appears to improve brain development and nerve growth. Because of its behavior as a prodrug and its pharmacokinetic differences, lisdexamfetamine has a longer duration of therapeutic effect than immediate-release dextroamphetamine and shows reduced misuse potential.
Amphetamine prescription shortages
Even ones available over the counter might interact with prescription medications like amphetamines. Because of this, some drugs only contain dextroamphetamine or have it in greater proportions. As it is a prodrug, lisdexamfetamine is structurally different from dextroamphetamine, and is inactive until it metabolizes into dextroamphetamine.
However, oral suspension and orally disintegrating tablet (ODT) dosage forms composed of the free base were introduced in 2015 and 2016, respectively. Many current amphetamine pharmaceuticals are salts due to the comparatively high volatility of the free base. The free base of racemic amphetamine was previously available as Benzedrine, Psychedrine, and Sympatedrine.
Adverse effects
As with other CNS stimulants, mixing amphetamines and other substances can lead to serious side effects and fatal overdose. These medications are available in various forms, including tablets, capsules, orally disintegrating tablets, and oral liquid solutions, and can be immediate-release or extended-release. While amphetamines are normally prescribed, there are illegal variants (as well as abused prescription medications) that are sold on the street for the purpose of abuse. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
Due to the effect pH has on absorption, amphetamine also interacts with gastric acid reducers such as proton pump inhibitors and H2 antihistamines, which increase gastrointestinal pH (i.e., make it less acidic). Acidic substances reduce the absorption of amphetamine and increase urinary excretion, and alkaline substances do the opposite. In general, there is no significant interaction when consuming amphetamine with food, but the pH of gastrointestinal content and urine affects the absorption and excretion of amphetamine, respectively.
Symptoms of overdose may include the following:
Amphetamine is a mix of dextroamphetamine and levoamphetamine. Many amphetamines treat multiple conditions. One amphetamine that doesn’t see any prescription use — but does see widespread nonmedical use — is MDMA.
Missed Dose
Similar to most biomolecules and other orally administered xenobiotics (i.e., drugs), amphetamine is predicted to undergo promiscuous metabolism by human gastrointestinal microbiota (primarily bacteria) prior to absorption into the blood stream. Following absorption into the blood stream, lisdexamfetamine is completely converted by red blood cells to dextroamphetamine and the amino acid L-lysine by hydrolysis via undetermined aminopeptidase enzymes. The immediate-release and extended release variants of salts of both isomers reach peak plasma concentrations at 3 hours and 7 hours post-dose respectively. Although preliminary observational evidence suggests potential benefit from adjusting amphetamine doses according to menstrual cycle phases, randomized controlled trials have not evaluated this practice. In December 2017, the first study assessing the interaction between amphetamine and human carbonic anhydrase enzymes was published; of the eleven carbonic anhydrase enzymes it examined, it found that amphetamine potently activates seven, four of which are highly expressed in the human brain, with low nanomolar through low micromolar activating effects. Acute amphetamine administration in humans increases endogenous opioid release in several brain structures in the reward system.
You may move the tablet around between the tongue and the roof of the mouth until it melts. Remove Adzenys XR-ODT® from the blister pack by peeling back the foil, then taking the tablet out. Do not open the blister pack that contains the tablet until you are ready to take it. You may divide the Dyanavel® XR 5-mg tablet into equal parts at the score line. You may chew or swallow the Dyanavel® XR tablet whole.
The dose of this medicine will be different for different patients. If you are using the extended-release oral disintegrating tablet, make sure your hands are dry before you handle the tablet. Measure the extended-release oral suspension with a marked measuring spoon, oral syringe, or medicine cup. If you feel that the medicine is not working properly after using it for several weeks, check with your doctor first and do not increase the dose. The presence of other medical problems may affect the use of this medicine. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Preclinical studies have also produced findings of sex-dependent differences in drug response to amphetamine. Reviews of human studies have also noted that men typically report stronger positive subjective responses to amphetamine compared to women tested during the luteal phase, whereas these sex differences are absent when women are tested during the follicular phase;sources 18 subjective responses to amphetamine appear to correlate positively with plasma or salivary estrogen concentrations. This increase in extracellular glutamate presumably occurs via the amphetamine-induced internalization of EAAT3, a glutamate reuptake transporter, in dopamine neurons. Extracellular levels of glutamate, the primary excitatory neurotransmitter in the brain, have been shown to increase in the striatum following exposure to amphetamine.
In contrast, levoamphetamine may have a greater effect on cataplexy, a symptom more sensitive to the effects of norepinephrine and serotonin. In addition, both a review and a meta-analytic systematic review found lisdexamfetamine to be superior to placebo in several secondary outcome measures, including persistent binge eating cessation, reduction of obsessive-compulsive related binge eating symptoms, reduction of body-weight, and reduction of triglycerides. This view is supported by the failure of anti-obesity medications and other appetite suppressants to significantly reduce BED symptom severity, despite their capacity to induce weight loss. While lisdexamfetamine’s anorexigenic effects contribute to its efficacy in BED, evidence indicates that the enhancement of cognitive control is necessary and sufficient for addressing the disorder’s underlying psychopathology.