Способ введения (путь заражения) — в фармакологии, токсикологии и медицине — путь введения лекарственного средства, жидкости, отравляющего вещества, инфекционного агента или другого вещества в организм.^[1]

Классификация

Классификация способов введения лекарственных средств и путей заражения инфекционными агентами основана на том, каким образом лекарственный препарат или инфекционный агент попадает в организм. Фармакокинетика и фармакодинамика лекарственного средства часто зависит от способа введения.^[2]

Место поступления

Энтеральное (внутрикишечное)

Введение препаратов и заражение инфекционными агентами через желудочно-кишечный тракт называют энтеральным введением. Как правило, энтеральное введение (заражение) подразумевает оральный прием препарата или оральное попадание инфекционного агента.^[3] Возможно также ректальное введение (через прямую кишку).^[3]

При этом, всасывание лекарственных средств, вводимых орально, часто происходит в желудке. Подъязычный и защечный прием также относят к энтеральному введению,^[3] хотя лекарственные средства при этом всасываются в проксимальной части желудочно-кишечного тракта и не достигают собственно кишечника.

Многие лекарства, например, таблетки, капсулы или капли обычно принимают орально. Существуют способы введения препаратов непосредственно в желудок (катетером). Известны примеры введения лекарств в двенадцатиперстную кишку при использовании дуоденальных катетеров. Некоторые таблетки имеют специальное покрытие, которое не растворяется желудке, но только в кишечнике.

Центральная нервная система

• эпидуральное введение — инъекция или инфузия в эпидуральное пространство, например, в случае эпидуральной анестезии
• интрацеребральное введение — инъекция непосредственно в мозг. Используют в исследованиях химических веществ^[4] и при лечении опухолей мозга^[5]
• интрацеребровентрикулярное введение — в желудочки мозга, используют в при опиоидной терапии терминальных стадий рака для снятия болей.^[6]

Другие

• epicutaneous or topical (application onto the skin). It can be used both for local effect as in allergy testing and typical local anesthesia, as well as systemic effects when the active substance diffuses through skin in a transdermal route.
• интрадермальное введение, (into the skin itself) is used for skin testing some allergens, and also for mantoux test for Tuberculosis
• subcutaneous (under the skin), e.g. insulin. Skin popping is a slang term that includes this method of administration, and is usually used in association with recreational drugs.
• назальное введение administration (through the nose) can be used for topically acting substances, as well as for insufflation of e.g. decongestant nasal sprays to be taken up along the respiratory tract. Such substances are also called inhalational, e.g. inhalational anesthetics.
• внутривенное введение (into a vein), e.g. many drugs, total parenteral nutrition
• intraarterial (into an artery), e.g. vasodilator drugs in the treatment of vasospasm and thrombolytic drugs for treatment of embolism
• внутримышечное введение (into a muscle), e.g. many vaccines, antibiotics, and long-term psychoactive agents. Recreationally the colloquial term 'muscling' is used.^[7]
• intracardiac (into the heart), e.g. adrenaline during cardiopulmonary resuscitation (no longer commonly performed)
• intraosseous infusion (into the bone marrow) is, in effect, an indirect intravenous access because the bone marrow drains directly into the venous system. This route is occasionally used for drugs and fluids in emergency medicine and pediatrics when intravenous access is difficult.
• intrathecal (into the spinal canal) is most commonly used for spinal anesthesia and chemotherapy
• intraperitoneal, (infusion or injection into the peritoneum) e.g. peritoneal dialysis
• Intravesical infusion is into the urinary bladder.
• intravitreal, through the eye
• Intracavernous injection, an injection into the base of the penis
• Intravaginal administration, in the vagina
• Intrauterine
  • Extra-amniotic administration, between the endometrium and fetal membranes

Route from application to target

The route or course the active substance takes from application location to the location where it has its target effect is usually rather a matter of pharmacokinetics (concerning the processes of uptake, distribution, and elimination of drugs). Nevertheless, the following routes are commonly referred to as routes of administration:

• transdermal (diffusion through the intact skin for systemic rather than topical distribution), e.g. transdermal patches such as fentanyl in pain therapy, nicotine patches for treatment of addiction and nitroglycerine for treatment of angina pectoris.
• transmucosal (diffusion through a mucous membrane), e.g. insufflation (snorting) of cocaine, sublingual, i.e. under the tongue, sublabial, i.e. between the lips and gingiva, nitroglycerine, vaginal suppositories

Местный или системный эффект

В зависимости от способа введения эффект от лекарственного препарата может быть местным (при наружном применении), либо системным (при энтеральном или парентеральном введении):

• topical: local effect, substance is applied directly where its action is desired.^[8] Sometimes, however, the term topical is defined as applied to a localized area of the body or to the surface of a body part,^[9] without necessarily involving target effect of the substance, making the classification rather a variant of the classification based on application location.
• enteral: desired effect is systemic (non-local), substance is given via the digestive tract.
• parenteral: desired effect is systemic, substance is given by routes other than the digestive tract.

Наружное

• epicutaneous (application onto the skin), e.g. allergy testing, typical local anesthesia
• inhalational, e.g. asthma medications
• enema, e.g. contrast media for imaging of the bowel
• eye drops (onto the conjunctiva), e.g. antibiotics for conjunctivitis
• ear drops — such as antibiotics and corticosteroids for otitis externa
• through mucous membranes in the body

Энтеральное

In this classification system, enteral administration is administration that involves any part of the gastrointestinal tract and has systemic effects:

• by mouth (orally), many drugs as tablets, capsules, or drops
• by gastric feeding tube, duodenal feeding tube, or gastrostomy, many drugs and enteral nutrition
• rectally, various drugs in suppository

Парентеральное

• внутривенное введение (инъекция в вену) применяют для многих лекарственных препаратов, парентеральный механизм заражения характерен для многих инфекционных заболеваний, например ВИЧ-инфекции и гепатита С
• интраартериальное введение (инъекция в артерию) используют при введении вазодилататоров при спазмах сосудов или тромболитиков для лечения эмболии
• внутрикостная инфузия — введение лекарства в костный мозг, является разновидностью внутривенного введения, так как костный мозг напрямую сообщается с венами. Данный способ введения лекарственных средств используют в неотложной медицине и в педиатрии в случае, когда внутривенное введение затруднено
• внутримышечное введение
• интрацеребральное введение (в паренхиму мозга)
• введение в желудочки мозга
• подкожное введение^[10]

Преимущества и недостатки

There are advantages and disadvantages to each route of administration

Ингаляция

Advantages

• The advantage of using an inhalatational method is that it allows the dose to be controlled more effectively
• User can titrate (regulate the amount of drug they are receiving)^[11]

Disadvantages

• Its a slower route of action, it has to be taken into the lungs, and then travels to the systemic circulation from there.

Инъекция

Injection encompasses intravenous (IV), intramuscular (IM), and subcutaneous (subcut)^[12]

Advantages

• Fast: 15-30 seconds for IV, 3-5 minutes for IM and subcutaneous (subcut)
• 100 % bioavailability
• suitable for drugs not absorbed by the digestive system or those that are too irritant (anti-cancer)
• One injection can be formulated to last days or even months, e.g., Depo-Provera, a birth control shot that works for three months
• IV can deliver continuous medication, e.g., morphine for patients in continuous pain, or saline drip for people needing fluids

Disadvantages

• Onset of action is quick, hence more risk of addiction when it comes to injecting drugs of abuse
• Patients are not typically able to self-administer
• Belonephobia, the fear of needles and injection.
• If needles are shared, there is risk of HIV and other infectious diseases
• It is the most dangerous route of administration because it bypasses most of the body’s natural defenses, exposing the user to health problems such as hepatitis, abscesses, infections, and undissolved particles or additives/contaminants
• If not done properly, potentially fatal air boluses (bubbles) can occur.
• Need for strict asepsis

Применение

• Some routes can be used for topical as well as systemic purposes, depending on the circumstan. For example, inhalation of asthma drugs is targeted at the airways (topical effect), whereas inhalation of volatile anesthetics is targeted at the brain (systemic effect).

• On the other hand, identical drugs can produce different results depending on the route of administration. For example, some drugs are not significantly absorbed into the bloodstream from the gastrointestinal tract and their action after enteral administration is therefore different from that after parenteral administration. This can be illustrated by the action of naloxone (Narcan), an antagonist of opiates such as morphine. Naloxone counteracts opiate action in the central nervous system when given intravenously and is therefore used in the treatment of opiate overdose. The same drug, when swallowed, acts exclusively on the bowels; it is here used to treat constipation under opiate pain therapy and does not affect the pain-reducing effect of the opiate.

• Enteral routes are generally the most convenient for the patient, as no punctures or sterile procedures are necessary. Enteral medications are therefore often preferred in the treatment of chronic disease. However, some drugs can not be used enterally because their absorption in the digestive tract is low or unpredictable. Transdermal administration is a comfortable alternative; there are, however, only a few drug preparations that are suitable for transdermal administration.

• In acute situations, in emergency medicine and intensive care medicine, drugs are most often given intravenously. This is the most reliable route, as in acutely ill patients the absorption of substances from the tissues and from the digestive tract can often be unpredictable due to altered blood flow or bowel motility.

Примечания