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Street drugs are synthetic derivatives of federally controlled substances, created by slightly altering the molecular structure of existing drugs and produced illegally in clandestine laboratories for illicit use and they are also called designer drugs. Most of these drugs have some psychoactive properties and cause visual disturbances, but they are not true hallucinogens like lysergic acid diethylamide (LSD).

Methylenedioxymethamphetamine

Many of the most popular designer drugs on the street today are amphetamine analogs. Methylenedioxymethamphetamine (MDMA) is one of the most commonly used designer drugs. Commonly known as Ecstasy, MDMA has central stimulant and psychedelic effects. Its use is popular among those attending late-night crave   parties, dance clubs, and rock concerts

• Mechanism of action: The main effect of MDMA is on neurons that synthesize and release the neurotransmitter serotonin (5-HT). MDMA causes 5-HT release into the synaptic cleft, inhibits its synthesis, and blocks its reuptake (Figure 43.9). The effect is an increased 5-HT concentration in the synaptic cleft and a depletion of intracellular 5-HT stores. 5-HT regulates mood, appetite, and body temperature. Users of MDMA will therefore manifest more of a serotonergic effect compared with the dopaminergic effects (amphetamine toxicity associated with amphetamines; see p. 121). MDMA's effects begin within the first hour after ingestion of an oral dose and usually last 3 to 6 hours.
• Clinical manifestations: 
  • Cardiopulmonary: Cardiopulmonary manifestations of Ecstasy use include tachycardia, tachypnea, hypertension, vasospasm, pulmonary hypertension, dysrhythmias, valvular disease, and myocardial infarction.
  • Neurologic: symptoms include mydriasis, nystagmus, head jerking, hyperthermia, sexual dysfunction, seizures, cerebral infarction, dopamine and 5-HT depletion in the synapse leading to potential for irreversible neuron destruction, and 5-HT syndrome, especially in combination with other serotonergic drugs.
  • Psychologic: Most users of Ecstasy describe a sense of well-being and social interactivity as well as feelings of empathy, euphoria, agitation, visual and tactile hallucinations, and occasionally, anxiety. Chronic abuse leads to symptoms of psychosis (from dopaminergic affects) and obsessive compulsive behavior.
  • Musculoskeletal: Common signs and symptoms include teeth-grinding (bruxism), jaw clenching (trismus), increased muscular activity resulting in cramping, and rhabdomyolysis.
  • Other manifestations: Dehydration and hyperglycemia are common, as is metabolic acidosis in chronic use and overdose. Hyponatremia is of concern because, as dilution, from increased water intake, in addition to increased diuresis, secondary to inhibition of antidiuretic hormone may reduce sodium, predisposing the patient to seizures and cerebral edema.
• Treatment: Treatment of isolated MDMA ingestion is supportive. Asymptomatic MDMA-induced hyponatremia is treated with fluid restriction. Refractory hypertension may be treated with nitroprusside or phentolamine. Hyperthermia is treated by aggressive external cooling with ice water, mist, and fans. Anxiety, agitation, and convulsions are treated with diazepam.

g-Hydroxybutyric acid

In the dance and crave clubs, γ-hydroxybutyric acid (GHB) has become widely abused due to its ability to rapidly produce a euphoric state. The fast and effective intoxication and the amnestic effect produced by GHB has made the drug attractive to sexual assault perpetrators. GHB is usually administered in an oral form and is rapidly and effectively absorbed by the gastrointestinal tract. The onset of action is quite rapid, with an effect usually being felt within 15 minutes and peaking anywhere between 40 and 120 minutes.

• Mechanism of action: The actions of exogenous GHB are mediated primarily by the GABAB receptor. Low doses of the drug stimulate dopamine synthesis but inhibit its release, causing dopamine to concentrate in the nerve terminal. With higher doses of GHB, dopamine release is triggered. GHB also has effects through the endogenous opioid system, which may explain its euphoria-producing properties.
• Clinical manifestations:
  • Cardiopulmonary: Chronic use of GHB can cause severe cardiopulmonary complications, such as hypoxia, bradycardia, hypotension, bradypnea, and dysrhythmia.
  • Central nervous system: CNS effects are common and include euphoria in small doses, deep sleep in moderate doses, and a comatose state in large doses. Amnestic effects and loss of sexual inhibition make GHB a common drug in the commission of sexual battery. Hallucinations, agitation (especially upon arousal), seizures, myoclonus, and slurred speech are also common.
  • Psychologic: Most users describe a sense of well-being and euphoria as well as being socially interactive and empathetic.
  • Other: Other physiologic manifestations include salivation, vomiting, and hypothermia.
• Treatment: Treatment of isolated GHB ingestion is supportive. In patients with significant CNS depression due to GHB overdose, intubation for airway protection is essential because of the high incidence of emesis. Bradycardia unresponsive to stimulation should be treated with atropine. Pentobarbital has been used successfully in the treatment of severe GHB withdrawal.