Pharmacology is a science that studies the effect of drugs on the human body, methods for producing new drugs. Even in Ancient Greece and India, in the tundra and in the southernmost region of Africa, people tried to find a way to fight the disease. In a sense, this became their obsession, a dream that was worth striving for.
Pharmacological terminology
Medicines are substances or their combinations that are used to treat a disease or as a preventative measure.
A drug is a drug that is already ready for use.
There are various forms of medication. This is done for ease of use and the possibility of an individual approach to the treatment of patients. In addition, due to the variety of forms of release, you can deliver the medicine to the body in several ways. This makes it easier to work with patients in an unconscious state, as well as with people who have received injuries and burns.
List A and B
All drugs are divided into three groups:
- list A (poisons);
- list B (potent drugs, including analgesics);
- over-the-counter medicines.
Class A and B drugs require increased attention, therefore a special prescription is needed to obtain them in the pharmacy network. In addition, you need to know where and how to properly store these medicines. Since they may well decompose in sunlight or acquire additional toxic properties. And some funds, such as morphine, are subject to strict reporting. Therefore, each ampoule is handed over by the nurses at the end of the shift with an entry in the appropriate journal. Some other drugs are also registered: antipsychotics, drugs for anesthesia, vaccines.
Recipes
A prescription is a written request by a doctor to a pharmacist or pharmacist with a request to sell a drug to a patient, indicating the form, dose and method and frequency of use. The form immediately performs the functions of a medical, legal and monetary document if medicines are issued to the patient on a preferential basis or without payment.
There is a legislative act that governs the rules for prescribing prescriptions for doctors of various specialties and positions.
A drug is not only a substance that can eliminate the disease or its manifestations, but also poison, so the doctor must correctly indicate the dosage when writing a prescription.
Doses
On the prescription form is written in Arabic numerals the amount of the drug in mass or volume units of the decimal system. Whole grams are separated by a comma, for example, 1.0. If drops are part of the medicine, then their number is indicated in Roman numerals. Some antibiotics are calculated in international (IU) or biological units (IU).
Medicines are substances that can be in solid, liquid or gaseous form. Liquids and gases in the prescriptions are indicated in milliliters, in case of inhalation, the doctor can note only the dose of dry medicine.
At the end of the prescription is the signature and personal seal of the doctor. In addition, the patient's passport data, such as surname, initials, age, are indicated. Be sure to put down the date of the prescription and its validity. There are special forms for recording prescriptions for preferential drugs, narcotic substances, sleeping pills, antipsychotics and painkillers. They are signed not only by the attending physician, but also by the head physician of the hospital, certified by his seal, and put a round seal of the medical institution on top.
It is forbidden to prescribe ether for anesthesia, fentanyl, chloroethane, ketamine and other soporific substances in the outpatient clinic. In most countries, prescriptions are written in Latin, and only recommendations for admission are written in the language that the patient understands. For narcotic and toxic substances, the validity of a sale permit is limited to five days, for medical alcohol - ten, the rest can be purchased within two months from the date of prescription.
General classification
In modern realities, when the most unusual drugs exist, classification is simply necessary in order to navigate in their variety. For this, several conditional guides are used:
- Therapeutic use - groups of drugs are used to treat one disease.
- A pharmacological action is the effect that a medicine produces in the body.
- The chemical structure.
- The nosological principle. It is similar to therapeutic, only the distinction is even narrower.
Group classification
At the dawn of the development of medicine, doctors tried to systematize medicines themselves. The classification as such appeared through the efforts of chemists and pharmacists, compiled according to the principle of the point of application. She included the following categories:
1. Psychotropic drugs and drugs acting on the central nervous system (tranquilizers, antipsychotics, sedatives, antidepressants, antiepileptic, anti-inflammatory).
2. Medicines acting on the peripheral nervous system (ganglion blockers, anticholinergics)
3. Local anesthetics.
4. Preparations that change the tone of blood vessels.
5. Diuretics and choleretic drugs.
6. Medicines that affect the organs of internal secretion and metabolism.
7. Antibiotics and antiseptics.
8. Antitumor drugs.
9. Diagnostic aids (dyes, contrast agents, radionuclides).
This and a similar division helps young doctors better understand existing drugs. Classification into groups helps to intuitively understand the mechanism of action of a particular drug and remember the dosage.
Classification by chemical structure
This symptom is most suitable for the classification of antiseptic and antimicrobial agents. There are bactericidal and bacteriostatic drugs. Classification by chemical structure covers both of these groups. The chemical structure of the substance reflects the mechanism of action of the drug and its name.
- Halogens. Basically, they have a chemical element of a halogen group: chlorine, fluorine, bromine, iodine. For example, antiformin, chloramine, pantocide, iodoform and others.
- Oxidizing agents. It is easy to guess that their mechanism of action is aimed at the formation of a large amount of free oxygen. These include hydrogen peroxide, hydroperite, crystals of potassium permanganate.
- Acids. They are used in medicine in large quantities. The most famous of them are salicylic and boric.
- Alkalis: sodium boric acid, bicarmint, ammonia.
- Aldehydes. The mechanism of action is based on the ability to remove water from tissues, making them more rigid. Representatives - formalin, formidron, lysoform, urotropin, urosil, ethyl alcohol.
- Heavy metal salts: mercuric chloride, mercury ointment, calomel, lapis, collargol, copper sulfate, lead patch, zinc oxide, Lassar paste, etc.
- Phenols. They have an irritating and cauterizing effect. The most common of them are carbolic acid, lysol.
- Dyes. They are used in diagnostic procedures and as a local irritant and antibacterial agent. These include methylene blue, brilliant green, fucorcin.
- Tar and tar, for example, Vishnevsky balm, Wilkinson ointment, ichthyol, paraffin, naphthalene, sulsen. Improve local blood supply to tissues.
Solid medicines
These drugs have the following representatives: tablets, dragees, powders, capsules and granules and other drugs. Determining the form of release is not difficult, since you can determine with your naked eye what exactly is in front of you.
Tablets are obtained by shaping a powder consisting of an active substance and an auxiliary. This is usually done under pressure.
Dragee is a layer-by-layer active and excipient pressed around a granule.
Powders have several uses. They can be drunk, sprinkled with wounds, diluted with saline and injected intramuscularly or intravenously. Distinguish between non-metered and metered powders, which, in turn, are simple and complex.
Capsules are a gelatin shell in which is a liquid, granular, powdery or paste-like drug.
Granules are most often found in homeopathic preparations, they look like small particles (no more than half a millimeter in size).
Liquid forms
This method of preparation includes solutions, galenic and novogalennye preparations, balms, collodions and other liquid and semi-liquid options.
Solutions are formed after mixing the drug substance and the solvent, for example, water or alcohol.
Galenic preparations consist only of plant extracts obtained by heating.
Infusions and decoctions are prepared from dry plants. Each of them is signed in the prescription, including the amount of solvent that the pharmacist should use.
Infusion and extract - on the contrary, alcohol-containing liquids. They can be either pure or alcohol-water or alcohol-ether. Novogalenovye preparations differ from conventional, galenic, high degree of purification of raw materials and finished product.
Special forms of medicine
Balms are oily liquids with deodorizing and antiseptic properties. Collodion is a solution of nitrocellulose with alcohol and ether in a one to six combination. They are used exclusively externally. Creams have a semi-liquid consistency and contain plant extracts mixed with a base, such as glycerin, wax, paraffin, etc. Lemonades and syrups are designed to make it easier for children to take medicines. This helps to make the small patient interested in the treatment process without additional efforts.
For injection, sterile aqueous and oily solutions are suitable. They can be as simple as complex. When writing a prescription, the dose of the substance and the volume in one ampoule are always indicated, as well as recommendations on where the drug should be administered.
Soft forms
If fatty or fat-like substances are used as the basis, then soft drugs are obtained. Definition, classification, the manufacturing process of these - all these questions are perfectly studied by chemists and pharmacists, but the doctor needs to know only the dose and indications for the appointment.
So, ointments should contain at least twenty-five percent dry matter. An appropriate consistency can be achieved by mixing the powders with animal fat, wax, vegetable oils, petroleum jelly or polyethylene glycol. The same criteria apply to pastes, but they should be more viscous. Liniment, on the contrary, should be more liquid, and they must be shaken before use so that the settled powder is evenly distributed inside the solvent. Candles or suppositories are solid, but when ingested, they quickly melt and become liquid. The patches are also hard at room temperature, but on the skin they melt and stick, forming a tight contact.
Medicines are substances of predominantly plant origin that have undergone chemical or physical processing so that the patient’s body can better absorb them.