Parenteral Therapy

Parenteral TherapyChapter 15

Parenteral Drug Preparation and Dispensing• Parenteral drugs are used for a variety of diagnostic,

therapeutic, and palliative indications• Requires prescription from physicians• Physicians’ orders require interpretation by a pharmacist• Pharmacists should know the patient’s age, weight,

diagnoses, and allergies

• The medication order may not give the pharmacist all the information needed to prepare doses.

e.g “Ampicillin IV 1 gram every 8 hours”

Intermittently or continuously; What the diluent will be; What the concentration of ampicillin in the diluent will be; What the hours of administration will be; The time over which the dose should be infused; How many doses to prepare

• The pharmacist must determine whether the dose is in an appropriate range for the patient, whether there might be an allergic reaction, and what incompatibilities to anticipate with other drugs being given by the same route• Pharmacist’s decisions: standardized or patient-specific• Parenteral routes of administration may be prescribed for a

variety of purposese.g fluid and electrolyte replacement, nutrition or as a vehicle for a

prescribed drug

•Packaging ampuls, glass or plastic vials, prefilled syringes, cartridges, glass

or plastic bottles, plastic bags, etc

• Most injections are aqueous solutions of a drug but there are some injections in the forms of colloidal dispersions, emulsions or suspensions

• Small volume parenteral (SVP) containers may contain a single dose or multiple doses of a drug in a volume no greater than 100 mL

- IV piggy-back container (e.g. minibags or minibottles in 50 mL or 100 mL sizes) that carry a diluent for the active drug

Small Volume Parenterals in the 2 to 5 mL range most commonly utilize a luer lock or luer slip fit (vented luer) top geometry. Syringes can be connected directly to the ampoules without a needle, creating an inherently safer delivery method.

Applications for Small Volume Parenterals include local anesthetics, vaccines, and other traditional injectable products. The 10 to 100 mL range is typically designed for multi-dose applications.

• Large volume parenterals (LVPs) are manufactured in bags or bottles up to 1000 mL

-common container sizes: 150 mL, 250 mL, 500 mL, and 1000 mL-typically contain fluids (e.g., sodium chloride 0.9%), nutrients (e.g.,

dextrose), and electrolytes (sodium or potassium chloride) or plasma volume expanders (e.g., albumin)

Large Volume Parenterals are typically injectable products designed for intravenous delivery applications. The large volume parenteral bottles are most often produced from a resin that can be autoclaved, either at 106° C or 121° C.

Infusion therapies fall into several categories that include the following and more:• Antineoplastic therapy (a.k.a cancer chemotherapy)• Biologic therapy (e.g., active and passive immunizations, allergen extracts,

monoclonal antibodies, etc)• Diagnostic agents (e.g., contrast media, skin tests)• Emergency treatments (e.g., autonomic drugs, antihypertensives)• Intravenous sedation• Parenteral solutions (e.g., fluids and electrolytes)• Parenteral drug therapy (e.g., antibiotics, hormones, etc.)• Parenteral nutrition (e.g., total parenteral nutrition)• Patient-controlled analgesia• Radiopharmaceuticals• Transfusions (i.e., blood and blood components)

Advantages of parenteral route administration

• An immediate physiological response can be achieved, which is a prime consideration in emergent clinical conditions such as cardiac arrest, or volemic shock• Parenterals are required for drugs that are not effective orally or that

are destroyed by digestive secretions, such as vaccines, insulin or some antibiotics• Medications for nauseated or unconscious patients must be

administered parenterally

•When desirable, parenteral therapy gives the health care provider control of the drug, since the patient must return for continued treatment, such as situations when patients cannot be relied on to take oral medication• Parenteral administration can result in local effects for drugs

as when local anesthetics or anti-inflammatory drugs are injected at the affected site

•When prolonged drug action is needed-long-acting steroids injected into joints-long-acting penicillins given by deep intramuscular injection

• Parenteral therapy provides a way of correcting serious disturbances of fluid and electrolyte balances•When food cannot be taken by mouth or tube feeding, TPN

requirements can be supplied into large veins

Hazards of Parenteral Therapy

• The dosage forms must be administered by trained personnel, and typically require more nursing time than those administered by other routes• Parenteral administration requires strict adherence to aseptic

procedures, and can cause some pain on injection• Once a drug has been given parenterally, it becomes more difficult to

reverse the physiological effects

• Because of manufacturing and packaging requirements, parenteral dosage forms are more expensive than similar drugs given orally• Infusion of a parenteral product or compounded preparation into a

vein can lead to phlebitis (inflammation of the vein) or thrombophlebitis (inflammation and a clot in a vein)


PHLEBITIS

Early sign: tenderness at the insertion site of the intravenous (IV) needle or cannula. As phlebitis worsens, the vein becomes red, warm and painful with edema and stiffnessLatter stages: the vein appears palpable, tender red cordDuration and effect: infusion phlebitis can last for a week or more, can induce fever, and predispose the patient to sepsis


Factors associated with infusion phlebitis• Type of needle used• Duration of drug therapy• Chemically irritating drugs• pH of the infusion• Osmolality of the liquid• Location of the IV site• Decreased blood flow• Possibly, the presence of particulate matter in the infusion


• Infiltration, extravasation, or the accidental intra-arterial injection of some drugs can cause necrosis resulting in tissue damage, even loss of a limb. Caustic or vesicant drugs (e.g., chemotherapy) or vasoconstricting drugs are most often implicated in these injuries.• Particulate matter has been reported in a variety of manufactured

and compounded parenterals, including large and small parenterals, dry-filled and lyophilized drugs, TPN, and others


• The intravascular infusion of excessive particulate matter may clog capillary beds, contribute to phlebitis, and cause formation of granulomas or foreign body reactions• Because of the hazards of particulate matter in compounded sterile

preparations (CSPs), pharmacists checking CSPs should view the finished preparation against light and dark backgrounds to detect visible particles or cloudiness• 0.22 micron, 0.45 micron or 5-micron filter -0.22 and 0.45 micron have the disadvantages of slowing the rate of IV administration and more frequent fliter blockage


INFECTION – due to the presence growth of a pathologic microorganism

• Intravenous infections:-infusate related-catheter related-administration delivery system related


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Parenteral Therapy