Commonly Abused Substances - Pharmacology

There are five groups of drugs that are commonly abused in the United States and in other developed countries. These are heroin, cocaine, cannabis, hallucinogens, and inhalants. Heroin is a Schedule I drug (see Chapter (An Inside Look at Pharmacology) ) that has no accepted medical use in the United States. Cocaine stimulates the central nervous system (see Chapter on CNS). Cannabis includes drugs such as marijuana and hashish.

Hallucinogens are drugs that alter perception and feeling. These include LSD, mescaline, psilocybin, and PCP. Inhalants are aerosols and volatile hydrocarbons such as airplane glue and paint thinner that give the drug abuser a “buzz” or feeling of euphoria.


Cannabis is an extract from the leaves, stems, fruiting tops, and resin of the hemp plant (Cannabis saliva). The most common form of cannabis is hashish. Hashish is the resinous material of the cannabis plant. Other forms of this drug includebanji, ganga, charas, kif, and dagga.

Hashish is classified as a controlled substance although it isn’t a narcotic derivative. Hashish also has sedative-hypnotic, anesthetic, or psychedelic properties and is capable of altering perception, thought, and feeling.

Hashish is administered orally using pipes or cigarettes and can be injected subcutaneously, however the most potent route is inhalation. Many drug abusers prefer smoking hashish through a water pipe to reduce the irritating effect of the acidic smoke. Some drug abusers grind hashish into a powder and mixed it with foods in order to delay the absorption of the drug by the body.

Hashish acts to depress the central nervous system and causes mental relaxation and euphoria that occurs within 15 minutes and lasts up to four hours. The drug abuser experiences a loss of inhibitions. The person’s time and space perceptionis altered and causes a free flow of ideas to occur. These ideas, however, are disconnected. The person can experience blanks or gaps in memory similarto an epileptic episode. The user may also have palpitations, loss of concentration, lightheadedness, weakness, tremors, postural hypotension, ataxia (staggering gait) and a sense of floating. As the dose increases, the effects of the drug progresses from relief to dis-inhibition, excitement, and anesthesia. Respiratoryand vasomotor depression and even collapse can occur with high doses. Hashish is metabolized in the liver and is eliminated in bile and feces. Only a trace amount of hashish is detectable in urine. Hashish may affect the metabolism of drugs that require protein binding. These include ethyl alcohol, barbiturates, amphetamines, cocaine, opiates, and atropine.

Hashish has withdrawal symptoms. These include minor discomfort for a few days. Insomnia, anxiety, irritability and restlessness may persist for a few weeks. The person may have intermittent craving for a few months, which is best treated by exercise. No pharmacological intervention should be given.


Hallucinogens are natural and chemically manufactured drugs that alter perception and feeling. These drugs alter the mind and change a person’s perception of time, reality, and the environment. Hallucinogens disrupt the normal activity of serotonin, which is a neurotransmitter that sends signals throughout the brain. Hallucinogens cause abnormal activation of serotonin in the part of the brain responsible for coordinating and processing hearing and sight. The result is that people taking hallucinogens hear voices and see images that don’t exist. Researchers are unsure if hallucinogens permanently alter the brain’s chemistry, however, some patient’s who have taken hallucinogens experience chronic mental disorders.

The following are commonly used hallucinogens.


Lysergide, better known as LSD, is a potent hallucinogenic that results in a psychoactive effect that heightens perception, creates distortions of the body, and causes visual hallucinations. The person taking LSD can experience unpredictable mood swings from euphoria to depression and panic, which is commonly referred to as a “bad trip.” LSD also causes hypertension, dilated pupils, hyperthermia, and tachycardia (rapid heart rate).

LSD takes effect within 20 minutes and lasts up to two hours altering the user’s state of consciousness. This can lead to psychosis and trigger flashbacks called “latent psychosis.” The experience is frequently unpleasant.

Acute panic and paranoia is a common side effect that can lead to homicidal thoughts and actions. The toxic effect of LSD causes impaired judgment and toxic delirium. This results in a stage of exhaustion and feeling of emptiness where the person is unable to coordinate thoughts. This fall into depression increases the risk of suicide. Some people who take LSD also enter into a longterm schizophrenic or psychotic reaction. LSD stimulates the uterus and could induce contractions in a pregnant woman.

Healthcare providers treat a person who is under the influence of LSD by using a “talk-down” approach where they talk the patient through the episode in a quiet, relaxed environment. If this approach fails, drug therapy is employed using a benzodiazepine such as diazepam (Valium). Drugs should only be used along with crisis intervention therapy.

Avoid using phenothiazines such as chlorpromazine (Thorazine). These can exacerbate the patient’s panic reaction and cause postural hypotension (low blood pressure when standing). Also avoid large doses of tranquilizers, using restraints, and isolating the patient because these interventions are more traumatic than therapeutic.


Mescaline is an alkaloid that is extracted from the flowering heads (mescal buttons) of the peyote cactus. Mescaline causes subjective hallucinogenic effects similar to LSD. The extract is a soluble crystalline power that can be dissolved into tea or placed in capsules for ingestion.

This drug takes effect almost immediately and lasts about six hours before it reaches its half-life and is excreted into the urine. People taking mescaline experience anxiety, hyperreflexia, static tremors, and psychic disturbances with vivid visual hallucinations. They also feel abdominal pain, nausea, and diarrhea.


Psilocybin is extracted from Mexican mushrooms. It produces a subjective hallucinogeniceffect that is similar to mescaline, but of shorter duration. Psilocybin takes effect in a half hour to an hour after the drug is administered and its effect can last up to six hours.

People who take this drug experience a pleasant mood although some users become apprehensive. This results in impaired performance and poor critical judgment. Some exhibit hyperkinetic (compulsive movements) behavior and inappropriate laughter. The pupils dilate and the person experiences vertigo (dizziness) and ataxia (stagger). They also have paresthesias (numbness, tingling) and muscle weakness. The drug also induces drowsiness and sleep.


PCP is a controlled substance called phencyclidine that causes hallucinations. Usage can result in assaults, murders, and suicides. PCP was developed in the late 1950s as a dissociative anesthetic that leaves a patient awake but detached from surroundings and unresponsive to pain. Once the drug’s hallucinogenic effect was discovered, PCP was withdrawn from use in humans, but continued to be used in veterinary medicine. PCP picked up the street name “hog” because of its use with animals.

PCP metabolizes rapidly in the liver and forms a high concentration in urine if taken in large quantities. A small dose of PCP has a half-life of between half an hour and 1 hour. Larger doses can have a half-life of 1 to 4 days.

Patients who are under the influence of PCP are flushed and sweat profusely. They have nystagmus (rapid eye movements), diplopia (double vision), and ptosis (drooping eyelids). These patients also appear sedated and under the influence of an analgesic. They also exhibit the effects of alcohol intoxication with ataxia (staggering gait) and generalized numbness of the extremities.

Patients undergo three stages of psychological effect when using PCP. The first stage is a change in body image and a feeling of de-personalization. This follows with the second stage when the patient’s hearing and vision become distorted. The third stage occurs when the patient feels apathy, estrangement, and alienation.

The patient’s thoughts become more disorganized. Attention span is impaired as is motor skills and overall sense of body boundaries. The drug’s hallucinatory effects can occur long after the patient’s acute symptoms are gone. These are unpredictable and can happen months after the drug was taken.

The patient can experience psychotic disturbances which are exhibited by paranoid behavior, self-destructive actions, random eye movement, and excitation. These are combined with physiological changes such as tachycardia, hypertension, respiratory depression, muscle rigidity, increased reflexes, seizures, and an unconscious state with open eyes.

There is no known chemical antidote to PCP. The only treatment is to keep the patient quiet, in a dark room, away from sensory stimuli, and protected from self-inflicted injury. Don’t attempt to talk the patient down as the patient can perceiveany interaction as a personal attack and may become very violent. The patient is commonly given diazepam (Valium) or haloperidol (Haldol) for their antianxiety and antipsychotic effects.

PCP is very toxic and nurses should be aware of the severity of the drug’s effects. These include hypertensive crisis, intracerebral hemorrhage (bleeding into the brain), convulsions, coma, and death. Patients who have used PCP should be closely monitored.


Inhalants are not drugs. They are volatile hydrocarbons and aerosols that are used to dispense a variety of chemical products that create a euphoric effect when inhaled. These products include airplane glue, paint thinner, typewriter correction fluid, lighter fluid, nitrous oxide, xylene, toluene, and include over 1000 household and commercial products. Treatment of abuse of inhalants uses a symptomatic approach rather than a pharmacological approach because there are no specific antidotes to these products. When inhaled, the intoxication can last a few minutes or several hours.

If used repeatedly, the individual can lose consciousness; high concentrations can cause heart failure or death. Some of the products can replace oxygen in the body and the individual can suffocate. Each of these side effects needs to be treated separately. The permanent health effects caused by the use of these inhalants can include hearing loss, peripheral neuropathies (numbness, tingling) or spasms of arms and legs, CNS or brain damage and bone marrow damage, that results in blood problems. Kidney and liver damage can also occur.

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