In Amphetamine Use Disorder, Though synthesis by Edleano in 1887, it was introduced in Medicine in 1932 as benzedrine inhaler, for the treatment of coryza, rhinitis and asthma. Later, it recommended for a variety of conditions such as narcolepsy, postencephalitic parkinsonism, obesity, depression, and even to heighten energy and capacity to work.
Amphetamine refers to a unique chemical which is basically phenyl-isopropylamine or methylphenethylamine. It is a powerful CNS stimulant, with peripheral sympathomimetic effects too. The dextro-amphetamine isomer is nearly 3-4 times more potent than the levo-isomer. It acts primarily on norepinephrine release in brain, along with an action on the release of dopamine and serotonin.
Although still clinically indicated for narcolepsy and attention deﬁcit hyperactivity disorder (and very rarely for obesity and mild depression), one of the commonest patterns of ‘use’ seen amongst the students and sports-persons to overcome the need for sleep and fatigue. Tolerance usually develops to the central as well as cardiovascular effects of amphetamines.
Recently, there has been a resurgence of amphetamine use in USA and Europe, with the availability of ‘designer’ amphetamines, such as MDMA (3,4-methylenedioxyamphetamine; street name: ecstasy or XTC).
Acute intoxication and Complications:
The signs and symptoms of acute amphetamine intoxication are primarily;
Cardiovascular: Tachycardia, Hypertension, Haemorrhage, Cardiac failure and Cardiovascular shock)
Central: Seizures, Hyperpyrexia, Tremors, Ataxia, Euphoria, Pupillary dilatation, Tetany and Coma).
The neuro psychiatric manifestations include anxiety, panic, insomnia, restlessness, irritability, hostility and bruxism. Acute intoxication may present as a paranoid hallucinatory syndrome which closely mimics paranoid schizophrenia. The distinguishing features include rapidity of onset, prominence of visual hallucinations, absence of thought disorder, appropriateness of affect, fearful emotional reaction, and presence of confusion. However, a conﬁdent diagnosis requires an estimation of the recent urinary amphetamine levels. Amphetamine-induced psychosis usually resolves within seven days of urinary clearance of amphetamines.
Chronic amphetamine intoxication leads to severe and compulsive craving for the drug. A high degree of tolerance is characteristic, with the dependent individual needing up to 15-20 times the initial dose, in order to obtain the pleasurable effects. A common pattern of chronic use is a cycle of runs (heavy use for several days) followed by crashes (stopping the drug use). Tactile hallucinations, in clear consciousness, may sometimes occur in chronic amphetamine intoxication.
The withdrawal syndrome is typically seen on an abrupt discontinuation of amphetamines after a period of chronic use. The syndrome is characterised by depression (may present with suicidal ideation), marked asthenia, apathy, fatigue, hypersomnia alternating with insomnia, agitation and hyperphagia.
Treatment of Intoxication:
Acute intoxication is treated by symptomatic measures;
- Hyperpyrexia (cold sponging, parenteral antipyretics),
- Seizures (parenteral diazepam),
- Psychotic symptoms (anti psychotics),
- Hypertension (anti hypertensives).
Acidiﬁcation of urine (with oral NH4Cl; 500 mg every 4 hours) facilitates the elimination of amphetamines.
Treatment of Withdrawal Symptoms:
The presence of severe suicidal depression may necessitate hospitalisation. The treatment includes symptomatic management, use of antidepressants and supportive psychotherapy. The management of withdrawal syndrome is usually the ﬁrst step towards successful management of amphetamine dependence.