0 +
0 +
Consultations per day
0 minutes
Average waiting time
0 %
Happy Patients

Drug toxicology

Omnia sunt venena, nihil est sine veneno. Sola dosis facit venenum. (łac.)

Toxicology is the study of poisons, i.e. substances which, when absorbed into cells in small amounts, cause severe body disorders or death. Aristotle believed that “poison and medicine are only a dose.” In turn, the father of toxicology, Paracelsus, formulated the thought: “Everything is poison and nothing is poison. The dose only decides if something is not poison. These claims can still be entered into modern pharmacology, because each chemical substance affects the human body and causes specific chemical reactions in it.

Drug Toxicology: Question mark arranged from drugs

Therefore, before each administration of a pharmaceutical, the patient and the doctor should thoroughly analyze the need to use a given substance and individually determine the possible negative aspects of this drug. There are no substances completely indifferent to the human body, and therefore completely non-toxic. We now know that apart from the dose, other factors can also influence the toxicity of a given agent. These factors include: the way of absorption of the toxic substance, the frequency of use, the duration of exposure, the extent of damage caused by the poison. Toxicology has been used in the prevention of addictions, it allows to determine the degree of dependence on a given chemical substance and its effects.

Administration of drugs is associated with the risk of side effects and adverse drug effects.

In terms of the adverse effects of drugs, the side effects of the drug, formerly known as side effects, and the drug’s toxic effects can be distinguished. Side effects are all those symptoms caused by a drug, apart from its main therapeutic effect, after administration in therapeutic doses. Toxic effects, on the other hand, are those side effects that occur after an overdose of the drug. It is acute or chronic poisoning.

  • The risk of developing these symptoms is often the greater the greater the therapeutic effect of the drug.
  • The occurrence of toxic symptoms is also related to the size of the dose.
    Virtually any drug, in a sufficiently large dose, can cause harmful effects and become poisonous.
  • Toxic effects may also occur as a result of long-term administration of therapeutic doses of drugs.

Toxicology: selected groups of pharmaceuticals and their toxicity.


    The toxicity of antibiotics for humans is due to their action on enzyme systems that are similar to those found in microorganisms. The most toxic are those antibiotics whose mechanism of action is to inhibit the biosynthesis of nucleic acids (polyene and polypeptide antibiotics and most anti-cancer antibiotics).

    Moderately toxic to humans are tetracyclines, macrolides, aminoglycosides and rifamycins. The mechanism of their action on a microbial cell is based on the inhibition of protein biosynthesis, which occurs in a slightly different way in the human body. Antibiotics that inhibit the biosynthesis of the bacterial cell wall (penicillins and cephalosporins) show the lowest toxicity to humans.


Toxicology: opioid analgesics

  This group includes opium alkaloids and their derivatives as well as synthetic narcotic analgesics. Morphine is a narcotic pain reliever of the opium phenanthrene alkaloids. It is quickly absorbed from the gastrointestinal tract. It easily penetrates all tissues, conjugates with glucuronic acid and excreted through the kidneys. In acute poisoning, there is a loss of consciousness. The following symptoms are observed: slower and shallow breathing, pinpoint pupils, cyanosis, contraction of the muscular membrane of the gastrointestinal tract and bile ducts, and a drop in blood pressure. Death due to respiratory failure may occur 2-4 hours after poisoning.

Toxicology: non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs have a lower pharmacological effect than narcotic analgesics. However, they additionally show anti-inflammatory and antipyretic effects, which is related to the inhibition of prostaglandin synthesis. The gastrointestinal tract is predominantly associated with the side effects associated with the use of NSAIDs. The most commonly observed symptoms related to the gastrointestinal tract are dyspepsia (epigastric pain, postprandial feeling of fullness or satiety), loss of appetite, belching, various types of abdominal pain, nausea and vomiting, worsening symptoms of gastro-oesophageal reflux disease and defecation rhythm disturbances – diarrhea, constipation, flatulence. Less common are weight loss, symptoms of gastrointestinal bleeding


Barbituric acid derivatives. Barbiturates are the most common cause of deliberate and accidental poisoning in the world. In medicine, they are used as sedatives, hypnotics, general anesthetics and anticonvulsants. Barbiturates are easily absorbed from the gastrointestinal tract. The rate of absorption depends on the lipophilic nature of the compound, the affinity for body proteins, and the concentration of the undissociated form of the drug. These properties also determine the ability to penetrate the body, the nature of distribution, and the degree of filtration and reabsorption in the renal tubules. The absorbed barbiturates are almost evenly distributed in all tissues. Larger amounts accumulate in the liver (high blood supply) and in the brain (good lipid solubility). They have the ability to penetrate the placental barrier and into milk. In the body, barbiturates are biotransformed. The resulting metabolites are devoid of biological activity, however, the derivatives form metabolites with a hypnotic effect after oxidation.

Benzodiazepine derivatives. Anxiolytics can deal with anxiety, emotional tension and feelings of anxiety. They also have a sedative, hypnotic, anticonvulsant effect, and relax skeletal muscles. Due to the wide range of action and frequent use, there is a great potential for poisoning and harmful effects.


Neuroleptic medications also have a calming effect. They tolerate the symptoms of psychosis and are used primarily in the treatment of schizophrenia. They can bear anxiety and reduce the sensitivity to external stimuli. They also show antiemetic, antihistamine and hypotensive effects. They intensify the effects of painkillers and sleeping pills. The main group of neuroleptic drugs are phenothiazine derivatives (aliphatic derivatives (chlorpromazine, promazine), piperidine (thioridazine) and piperazine derivatives (perphenazine, fluphenazine, triflupenazine). heart, orthostatic drop in blood pressure, orientation disorders, increasing somnolence, leading to coma, convulsions, cyanosis of integuments. Death occurs as a result of respiratory paralysis or complications related to prolonged coma. The lethal dose of phenothiazines for humans is 15-150 mg / bw Extrapyramidal system disorders may occur with prolonged use of phenothiazines, such as parkinsonian symptoms (increased muscle tension, slowness of movement, tremors of the limbs and head), dystonia and dyskinesia (compulsive movements of the head and neck, facial expression muscles, etc.). language , twists of the torso, difficulty swallowing), akathisia (restlessness requiring frequent changes of body position). Phenothiazine derivatives cause allergic skin reactions (urticaria, contact inflammation, photoallergic reactions). Long-term ingestion of high doses can lead to changes in skin pigmentation and a deposition of dye in the cornea and retina of the eye.


Caffeine has a stimulating effect on the central nervous system and is rarely fatal in humans. Fatal intoxication has been reported after the ingestion of 500 mg of caffeine and its intravenous administration in a dose of 3.2 g. It is believed that 10 g of caffeine administered orally may be fatal to humans. Acute caffeine poisoning causes significant psychomotor agitation, increased heart rate, cardiac arrhythmias, increased blood pressure and convulsions. Death may occur as a result of irritation of the respiratory center. Excessive caffeine consumption leads to chronic intoxication characterized by excessive psychomotor agitation, racing thoughts, anxiety, increased heart rate and excessive diuresis.


  1. Seńczuk, Contemporary toxicology, PZWL,
  2. Jurowski, W. Piekoszewski, Toxicology Tom ½, PZWL,
  3. Samborski, K. J. Filipiak, J. Kaczmarczyk, A. Tykarski, Non-steroidal anti-inflammatory drugs and cardiovascular and gastroenterological complications – selection algorithm, Heart and Vascular Diseases 2016, vol. 13, no. 4

Share this post

Share on facebook
Share on twitter
Share on linkedin
Share on whatsapp
Share on email

This website uses cookies to provide services at the highest level. By continuing to use the site, You agree to their use. You have to accept to use the site