AMPHETAMINES
Amphetamines are central stimulants but they are frequently used as drugs of abuse. This we will see in a separate article in the other blog 'MAS PHARMACY AND HEALTH REVIEW'
Amphetamine is generally an equal mixture of the two enantiomers the Levo and dextro amphetamines
Further amphetamines are available in the market as follows:-
1.Methylamphetamine (Ritalin)
2.Methamphetamine (Methedrine or 'speed')
3.Dextroamphetamine (Dexedrine)
4.MDMA ('ecstasy')-Methylene Dioxy Meth Amphetamine
5.Bupropion
Amphetamines are chemically a derivative of the endogenous phenylethylamine.
Mechanism
Amphetamines are powerful central stimulants work by releasing norepinephrine and dopamine from their storage.
Physiology
Amphetamines by stimulating CNS through the release of catecholamines they mainly affect sleep centers of the hypothalamus which regulates the sleep cycles.
1. Amphetamine causes euphoria to the individuals who are addict to it. Euphoria is a kind of daydream or imagination of impossible thoughts associated with belief and confidence.
2. CNS stimulation reduces tiredness and fatigue, improves alertness, and cognitive ability.
3. Elevate B.P-Hypertension.
4.Elevate breathing
5. Blunts hungry.
6. Amphetamine is an aphrodisiac, a drug that stimulates sexual desire.
Clinical Use
1.To improve sleep disorders(Anti-Narcoleptic)
2.Attention Deficit Hyperactivity Disorders(ADHD)
3.Appetite Control.
Route Of Administration
Oral
Metabolism and Kinetics
Amphetamine is well absorbed orally and 75 % is bioavailable in case of dextroamphetamine.
Amphetamine is a weak base with a pH of 9.9 and in the alkaline gut, it easily gets dissociated into the highly lipid-soluble free base and easily absorbed by the fatty gut villus.
15 to 40% are absorbed by the plasma proteins
Amphetamine is metabolized in the liver and excreted in the urine.
Amphetamine is eliminated by the body within two days of the last dosage taken.
Elimination is increased and the half-life is decreased by acid diets and vice versa.
Contraindication
Amphetamine should not be taken by those who are using MAOIs for their mobility disorders. Because MAO should not be inhibited any way if amphetamine is in usage as amphetamine is acting by releasing catecholamines from their stores which are metabolized by MAO. Inhibiting MAO will result in an excessive adrenergic crisis.
Adrenergic Crisis Treatments
Chlorpromazine a neuroleptic is the drug of choice to neutralize amphetamine poisoning as it effectively blocks the alpha-adrenergic receptors which are responsible for CNS disturbances and hypertension.
