Variations may be noticed in the way that units are marked on the scale, but, in general, the shorter lines represent 2 units of insulin, whereas the longer lines measure 10 units of insulin. Low-dose insulin syringes see Figure , B may be used for patients who are receiving 50 units or less of U insulin.
The shorter lines on the scale of the low-dose insulin syringe measure 1 unit, whereas the longer lines each represent 5 units. When traveling abroad, be aware that U concentration insulin i. A specific insulin syringe that has been calibrated for U insulin should be used with the U insulin. Insulin delivery aids e. Life Span Considerations. The tuberculin syringe see Figure , which makes use of the metric system of measurement, will provide the most accurate measurement for doses of parenteral medications of 1 mL or less.
The practice of adding 0. Check institutional policy regarding medication administration for the procedure to be used. Several manufacturers supply a premeasured amount of medication in a disposable cartridge—needle unit or prefilled syringe. These units are marketed under the brand name Carpuject.
The cartridge contains the amount of drug for one standard dose of medication. The drug name, concentration, and volume are clearly printed on the cartridge. The Carpuject prefilled cartridges require a holder that corresponds with the type of cartridge used Figure Advantages of the prefilled syringe include the time saved in preparing a standard amount of medication for one injection and the diminished chance of contamination between patients and hospital personnel; the cartridge is in a sealed unit, which is used once and then discarded.
Disadvantages include additional expense, the need for different holders for different cartridges, and the limitation of the volume of a second medication that may be added to the cartridge.
Many hospital pharmacies prefill syringes for specific doses of medication for some patients. Insulin is also available in a prefilled syringe known as an insulin pen Figure When capped, these pens look very much like ink pens, which allows the patient to carry insulin in a discreet manner. When needed, the cap is removed, a needle is attached, air bubbles are removed, the dose is dialed in, the needle is inserted into the subcut tissue, and a trigger is pushed to inject the measured dose.
When finished, the needle is removed and the cap replaced, and the device again takes on the appearance of a pen. These pens are available in a variety of colors and styles, including a prefilled, disposable model; a smaller, low-dose model; and a refillable model into which a new cartridge can be inserted when needed.
The patient should be instructed regarding the correct method of holding the pen and reading the dosing dial as indicated by the manufacturer; this will help to prevent dosing errors. Another type of prefilled syringe is the EpiPen Figure This syringe is a disposable automatic injection device that has been prefilled with epinephrine for use in an emergency, such as that caused by an allergic reaction to insect stings or bites, foods, or drugs.
When held perpendicularly against the thigh and activated, a needle penetrates the skin into the muscle, and a single dose of epinephrine is injected into the muscle. This product is available in adult and pediatric dosages for use at home or when traveling for those who have strong reactions when they are exposed to allergens.
It is important to educate those who are carrying these prefilled syringes to monitor the expiration date of this medication on a regular basis.
Excipients can be added to increase the stability or solubility of the drug. They must be airtight to maintain the sterility of the preparation prior to use.
In medicine and pharmacy, enteral administration is the term used to describe drug administration via the gastrointestinal tract. The majority of medicines are administered orally via this route in the form of tablets, capsules or liquids. The enteral route also encompasses rectal administration utilizing dosage forms such as suppositories, enemas or rectal ointment. In contrast to this, the term parenteral administration literally means any method of drug administration which does not utilize the gastrointestinal tract, such as by inhalation or application to the skin.
In practice however, parenteral administration is commonly taken to mean drug administration by injection. In this chapter, we will explore why the parenteral route of administration may be chosen by the clinician or the manufacturer of a medicine.
The routes available for parenteral administration and the tissues, organs and anatomical spaces that can be accessed by injection are outlined. The various forms or types of parenteral product commonly manufactured are described and the pharmacopoeial standards for injectable products are discussed. The ingredients of formulated injectable products with regard to vehicles or solvents, excipients and preservatives are described along with physiological considerations, such as the pH and tonicity of the product prior to administration.
Finally the containers, closures and primary packaging commonly used for parenteral products are discussed. The vast majority of patients would prefer to receive their medication as an oral tablet or liquid to swallow, or as a cream, ointment or transdermal patch to apply to the skin rather than receive treatment via injection, which can be painful or stressful indeed some patients suffer from needle phobia. There are, however, a number of clinical advantages associated with parenteral administration.
Many medicines are administered parenterally simply because the drug molecule itself would be rapidly broken down in the gastrointestinal tract and would thus become inactivated before it could be absorbed into the circulatory system. Good examples of this are aminoglycoside antibiotics, such as gentamicin.
The injectable route may be chosen to provide a highly localized effect. This is particularly true when the injection route accesses a particular anatomical area or organ system. Examples of this include the injection of drugs, such as steroids, into joint spaces intra-articular injection , intra-ocular injections to treat eye diseases or intrathecal injections where medicines are administered into the spinal column to deliver drugs into the cerebrospinal fluid, that otherwise might not accumulate sufficiently in this tissue to achieve the desired effect.
Intravenous injection delivers the drug directly into the circulatory system, where it is then rapidly distributed around the body.
This is important clinically as the drug will rapidly produce an effect, whereas peak blood levels may not be achieved for one to two hours after a drug is administered orally. This rapid onset of action for an intravenously administered drug may be critical in emergency situations. Conversely, by choosing to administer a drug by intramuscular injection, the release of the medicine from the injection site into the circulation can be delayed and prolonged.
Indeed, as will be seen later, by manipulation of the formulation of intramuscular injections it is possible to provide prolonged drug release allowing doses to be required at only once-monthly intervals. Finally, the intravenous route of injection is routinely used to administer medication to the unconscious patient who is unable to swallow.
This route is also employed in conscious or unconscious patients if the gastrointestinal tract is not working. In this scenario, not only are medicines, but fluids for hydration and electrolyte replacement, plus all the nutrients, vitamins and trace elements normally obtained from a healthy diet supplied by parenteral nutrition provided intravenously. As noted above medicines are injected by many different routes and the choice of route is governed by the purpose of the treatment and the volume of medicine to be administered.
Intravenous IV or i. The volumes administered can range from 1 mL for an intravenous injection, up to several litres for an intravenous infusion. Medicines administered by intravenous injection or intravenous bolus dose will rapidly increase the concentration of the drug in the plasma and produce a rapid effect. If the medicine is first added into a large volume of fluid mL to 1 L infusion bag and then administered by intravenous infusion at a slow and controlled rate, often utilising a pump, the drug will enter the circulation at a much slower and controlled rate.
Therefore, the sublingual route has a faster absorption rate when compared with the oral route. The sublingual route of drug administration has an advantage of bypassing the liver first pass effect. As a result, a lower dose of the drug is required when compared with the oral route. Excess drug can be spat out. The dosage forms used sublingually include the sublingual tablets, strips, drops, and sprays.
The buccal route is the route of administration where the medicine is placed between the gums and the inner lining of the cheek. This route of administration has the same advantages as of sublingual route but the difference is the site of application. Drugs used by this route include fentanyl buccal patches, nicotine tablets as smoking cessation aid and prochlorperazine in treating nausea and vomiting.
The rectal route offers a faster, safer, and low cost route of administration when compared to several other alternative routes. The dosage forms of the rectal route of administration include suppositories and enemas. A drug administered rectally has a faster onset of action, high bioavailability, and produces less nausea when compared with the oral route. The rectal route of administration undergoes less first pass effect and the drug concentration is also reduced only to a slighter extent from actual drug concentration.
The disadvantage of a rectal route is an erratic or irregular absorption, and the unacceptability of the route by some patients. Parenteral route of drug administration means administering the drug through routes that bypass the digestive tract, through injections. The administration requires skilled medical personnel who administer the medication with the help of a syringe and needle or a catheter using aseptic precautions. The cost is higher than that of oral dosage forms and involves the pain of the prick of the needle, which may be scary for some.
The most commonly used parenteral routes of administration are subcutaneous, intravenous, intramuscular, and intradermal injections. Intradermal route of drug administration involves injecting the medication into the dermis, a layer just below the epidermis of the skin. The amount of drug administered through this route is usually less than 0. This route has the longest absorption time among parenteral medications and is often used for diagnostic purposes for tests such as penicillin sensitivity, diphtheria test and Dick test for scarlet fever.
The BCG vaccine for tuberculosis is also administered intradermally. A subcutaneous injection is administered under the skin into the fat layer just below the dermis of the skin. The absorption from the subcutaneous route is slow and sustained action as the tissue sites have fewer blood vessels. It has a slower action compared to intravenous but faster than an intradermal route. Drugs used: Measles vaccine , insulin, morphine, and goserelin a drug used to suppress sex hormones.
Injection sites: Outer area of the upper arm, abdomen, upper thigh, upper back, and upper area of the buttock. The intramuscular route of drug administration involves injecting the medicine directly into the muscle.
As muscles are rich in large blood vessels, the absorption rate is faster than subcutaneous and intradermal routes. When parenteral fluids are discontinued both must be cancelled by the prescriber. An exception to this is an already established infusion which has been instigated by another practitioner following the principles set out above, or medication prepared under direction of a pharmacist from a central intravenous additive service and clearly labelled for that patient.
Prior to the preparation of a new medication a risk assessment must be performed to identify the most appropriate location for its preparation. Student nurses and midwives can administer parenteral medicine, including Intravenous IV medicine administration with a compatible flush and Sodium Chloride 0. Sodium Chloride 0.
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