Pain is always undesirable and unexpected. The appearance of pain signals a malfunction in the body, and sometimes( with malignant tumors, labor, severe trauma), it can not be avoided at all. Fortunately, there are highly effective drugs that can even overcome unbearable pain. These are analgesic drugs of the narcotic series.
Narcotic analgesics
Drugs for the removal of pain syndrome include drugs that have activity primarily in relation to opioid receptors in the brain. With the use of narcotic drugs, the sensation of pain gradually disappears, a feeling of agonizing expectation of a new attack passes, but the patient is in full consciousness and the sensitivity of the tissues to any effects is preserved.
All narcotic pain relievers are divided into:
- agonists of opioid receptors;
- agonists are antagonists;
- antagonists.
The first two species have a directed action against severe pain, the third - removes from the state of poisoning caused by an overdose of opiates.
Classification of narcotic painkillers
All narcotic analgesics can be divided into three large groups:
- of natural origin. These include opioids derived from the hypnotic poppy - morphine and codeine.
- Semisynthetic substances - ethylmorphine, omnopon. These painkillers are obtained by changing the molecule of a natural substance - morphine.
- Synthetic analgesics. They include all drugs that are completely synthesized by man and have no analogues in nature. These are promedol, fentanyl, sufentanil, buprenorphine, etc.
In addition to dividing drugs by source of origin, pharmacologists classify narcotic substances by chemical formula.
In this case, they can be divided into 4 groups:
- Derivatives of morphine. This includes all known morphine and codeine - natural preparations, as well as their synthetic substitutes - nalorphine, pentazocine, buprenorphine, butorphanol, nalbuphine.
- Derivatives of piperidine. These include promedol, sufentanil, fentanyl, pyrithramide( better known as dipidolor), imodium, loperamide.
- Derivatives of cyclohexane. They belong to the group of agonist-antagonists of opiate receptors, and in this connection they cause less addiction than the previous groups of drugs. This group includes tramadol, tilidine, valoron.
- Acyclic. Of this group, only estocin is currently used.
Mechanism of action
The mechanism of the appearance of pain is very complicated. The human body has special nerve endings that react to external or internal irritating factors - nociceptors. The pain stimulus, passing along the nerves, enters the spinal cord, developing sensitivity to pain, and then sent to the brain, which processes the extracted information and stimulates the response mechanism.
The body reacts differently to sharp and prolonged, aching pain. A sharp pain is unexpected and accompanied by an instant movement - so the hand is removed from the burning flame. Longing pain is accompanied by painful sensations and certain reactions of the body - nausea, dizziness, sweating, heart palpitations.
Narcotic substances bind to opiate receptors, activate them and, depending on the analgesic, cause the following effects:
- increase the endurance of the body to pain stimuli;
- reduces the body's response to painful bursts;
- relieves the feeling of fear of impending severe pain, contributes to the weakening of strong emotions and experiences associated with pain.
Opiate receptors are not only on the path of pain impulses, but also in the spinal cord and brain. Opiates penetrate well through any barriers and get into, including, the brain. Hence, there is such a secondary effect as euphoria. Taking an opioid analgesic, a person calms down, hallucinations may occur, condescension condescends and fears and negative experiences directly related to painful feelings disappear.
Dependence development
Having experienced a pleasant feeling of bliss and relaxation, a person tries to return these sensations and starts taking the medications again. So the psychic dependence on the administration of drugs is formed.
With constant intake of opium, the body stops responding to a previously helping dosage, tolerance is formed. To get a state of appeasement again, you must enter a higher dose. Gradually, the body ceases to produce endogenous substances that contribute to the easing of pain, so if withdrawal from anesthesia begins withdrawal syndrome. Thus, physical dependence on narcotic drugs develops.
Indications
Due to the high risk of dependence formation, narcotic drugs are not shown to all patients and are used for anesthesia only in emergency cases:
- Prolonged, very severe pain in malignant neoplasms.
- Management of pain syndrome in case of burns.
- Anesthesia in childbirth.
- Achieves antitussive effect in chest injuries.
- Anesthesia in case of myocardial infarction.
- Premedication for anesthesia.
- Postoperative analgesia.
Side effects of
Absolutely all narcotic drugs have a negative effect on the body, especially the central nervous system. Patients can tolerate some painkillers better, others - a little worse, it depends on the sensitivity of a person to these or other components of the drug.
Especially often, patients taking analgesics in the recommended dosage complain of problems with the gastrointestinal tract, manifested in constipation. In this case, life is facilitated by laxatives. In some patients with pronounced symptoms of inflammation of the intestine, narcotic analgesics can cause the development of a toxic megacolon.
Side effect of the central nervous system is expressed in the achievement of euphoria, narrowing of the pupils, respiratory depression. As a result, patients with impaired respiratory function should take narcotic drugs in a reduced dosage.
Often the side effect of the action of analgesics is a delay in the release of urine.
The influence of painkillers on the heart and blood vessels was noted, which is expressed in the reduction of arterial pressure, especially with intravenous medication.
Contraindications
There are categories of patients who should never prescribe narcotic drugs to relieve pain sensitivity.
Any narcotic analgesics are contraindicated for:
- for children under two years;
- patients with respiratory failure;
- persons with symptoms of "acute abdomen" before finding out the causes of the pathological condition;
- patients with traumatic brain injury;
- persons with drug dependence.
When prescribing narcotic analgesics, you should repeatedly be especially careful with the following group of patients:
- pregnant and lactating mothers;
- impaired liver function and renal failure;
- is old age.
Acute poisoning and overdose of
If the dosage prescribed by the doctor is exceeded in order to relieve pain in patients, the symptoms of acute drug intoxication develop. It is nothing but intoxication with narcotic drugs.
Symptoms of
Begin to develop such signs:
- initial excitation, disinhibition, excessive fun and talkativeness;
- sensation of heat in the body, the face itches and itches, the mouth is very dry, the appearance of red spots on the body.
An overdose of analgesics often occurs when a deliberate use of an increased dosage of a drug in order to obtain a side effect from an anesthetic - a state of bliss. Therefore, narcotic drugs should be kept away from public places, so that neither children nor the patients themselves can use medicines unattended.
In cases where an overdose is significant, the patient may fall into a coma.
For a strong overdose of opiates, there are signs such as:
- sharp pupil narrowing;
- convulsions;
- violation of breathing - it can become superficial or rare, in other cases and completely absent;
- blue skin of the face;
- decrease in pressure and body temperature.
On the video about symptoms of poisoning with narcotic analgesics:
Treatment of
Patients with severe intoxication with opium drugs should be immediately delivered to the intensive care unit. The most effective drug for the treatment of opium poisoning is naloxone.
Naloxone is an antagonist of opium receptors. Simply put, this drug "displaces" morphine from the receptors, which causes improvement in respiratory function, dilated pupils and the return of consciousness. If this does not happen, then there is a probability that the patient is not in drug intoxication.
In parallel with the administration of naloxone, the patient undergoes gastric lavage, a number of analeptics, nootropics, vitamin preparations and antibacterial agents are prescribed.