Hematopoiesis and Erythropoiesis-Stimulating Agents

Hematopoiesis

• Hematopoiesis is the process of new blood cells being made, they can be red blood cells (RBCs), white blood cells (WBCs) and platelets
• Red blood cells are manufactured in bone marrow
• Immature red blood cells are called reticulocytes
• Red blood cells have a lifespan of 120 days
• More than one third of a red blood cell is composed of hemoglobin
• Hemoglobin contains heme, which is a red pigment containing iron and globin, which is a protein chain

Erythropoiesis-Stimulating Agents

• Epoetin alfa (Eprex®) is a biosynthetic form of erythropoietin, which is used for the treatment of anemia

• This can include anemia caused by end-stage renal disease, chemotherapy, or anemia associated with zidovudine therapy

• The medication is ineffective without adequate body iron stores and bone marrow function

• Most clients also need to receive an oral iron preparation

• Darbepoetin (Aranesp®) is a longer-acting form of epoetin alpha

• Contraindications include drug allergy, uncontrolled hypertension, hemoglobin >100 mmol/L for cancer patients and >130 mmol/L with kidney disease, head and neck cancers and any risk of thrombosis

• Frequent adverse effects hypertension, fever, headache, pruritis, rash, nausea, vomiting, arthralgia, and injection site reaction

• Epoetin alfa is banned in athletics

Iron

• Iron is an essential mineral, that is stored in the liver, spleen, and bone marrow

• Oxygen is carried in hemoglobin and myoglobin by iron

• Iron deficiency will result in anemia

• Dietary sources for iron: meats, certain vegetables, and grains

• Dietary iron must be converted by gastric juices before it can be absorbed

• Some foods enhance iron absorption and some foods impair iron adsorption

• Orange juice, veal, fish, and ascorbic acid enhance iron absorption

• Eggs, corn, beans, cereal products containing phytates can impair iron absorption

• Iron may be given as a single drug or as part of a multivitamin

• Oral iron preparations are available as ferrous salts

• Examples of ferrous salts: ferrous fumarate (Femiron®), ferrous gluconate, ferrous sulphate (FeSO4)

• Elemental dosage of iron can be 50-100mg 2-3X/day

• Ferrous sulphate 324mg contains 65mg elemental iron

• Parenteral iron forms are: iron dextran (Dexiron®, Infufer®), iron sucrose (Venofer®), ferric gluconate (Ferrlecit®), ferumoxytol (Feraheme®)

• Indications for using iron: prevention and treatment of iron deficiency syndromes, alleviates the symptoms of iron deficiency anemia and the underlying cause of the anemia should be corrected

• Common adverse effects of iron use: pediatric poisoning deaths, nausea/vomiting, diarrhea, constipation, stomach cramps and pain, black, tarry stools, liquid oral preparations temporarily discolour teeth and injectable forms cause pain upon injection

• Symptomatic and supportive measures for iron toxicity includes: suction and maintenance of the airway, correction of acidosis, IV fluids or blood, oxygen and vasopressors

• Chelation therapy with deferoxamine mesylate, for severe iron intoxication (coma, shock, or seizures)

• Iron dextran (Dexiron, Infufer) may cause anaphylactic reactions, major orthostatic hypotension and death

• A 25 mg test dose of iron dextran must be administered before injection of the full dose, the remainder of does given after one hour

• Ferric gluconate (Ferrlecit) has a lower risk of anaphylaxis and no test dose is required

• Doses higher than 125 mg of Ferric gluconate are associated with increased adverse effects such as abdominal pain, dyspnea, cramps, and itching

Folic Acid

• A water-soluble, B-complex vitamin
• Folic acid is essential for erythropoiesis
• It has primary uses for folic acid deficiency and to prevent neural tube defects during pregnancy
• Malabsorption syndromes are the most common causes of deficiency
• Folic acid should not be used until the actual cause of anemia is determined
• Folic acid may mask symptoms of pernicious anemia, which requires treatment other than folic acid
• Untreated pernicious anemia can progress to neurological damage

Cyanocobalamin (Vitamin B12)

• Cyanocobalamin is used to treat pernicious anemia and other megaloblastic anemias
• It can be administered orally or parentally

Nursing Implications for Anemia

• Do not shake Erythropoiesis-Stimulating Agents (ESAs)
• Pills containing iron should especially be kept away from children, oral forms may appear like candy
• Iron dextran is contraindicated in all anemias apart from iron-deficiency anemia
• For liquid iron preparations, follow the manufacturer's guidelines on dilution and administration
• Patients should be instructed to take liquid iron preparations through a straw to avoid staining tooth enamel
• Oral forms of iron should be taken between meals for maximum absorption, but can be taken with meals if GI distress happens
• Avoid taking iron with milk or antacids
• Oral forms of iron should be given with juice (instead of milk or antacids)
• Clients should remain upright for up to 30 minutes after taking oral iron doses to avoid esophageal corrosion
• Administer IM dose deeply into a large muscle mass, using the Z-track method

Functions of the Skin

• The skin functions as a protective barrier for the internal organs
• It senses change in temperature, pressure and pain
• The skin regulates body temperature, excretes fluid and electrolytes, stores fat and synthesizes vitamin D
• It also provides a site for drug absorption

Topical Dermatological Drugs

• Topical dermatological drugs include: antibacterial, antifungal and antiviral drugs, anti-inflammatory and antineoplastic drugs, antipruritic and burn drugs, emollients, keratolytics, local anaesthetics, topical vasodilators, debriding drugs and sunscreens

• Available topical drug forms:

  • Aerosol foam can cover large areas; useful for drug delivery into a body cavity (e.g., vagina, rectum) or hairy areas
  • Aerosol spray spreads a thin liquid or powder film; typically used with skin that is tender from burns
  • Cleansers are nongreasy, used as an astringent or as a wash with water
  • Creams can be removed with water; not greasy or occlusive; good for moist areas
  • Gel/jelly contains water, easily removed and a good lubricator; useful when lubricant properties are desirable
  • Oil has little if any water; occlusive, liquid; not removable with water
  • Ointment contains no water; not removable with water; occlusive, greasy, and semisolid
  • Paste contains more powder than ointments; excellent protection agent
  • Pledget (pad) is moistened and is applied to or wiped over affected area
  • Solutions are nongreasy liquids that dries quickly
  • Sticks spread a thin chalky or viscous liquid film
  • Tape is a moist occlusive formulation

Antibacterial Drugs

• Antibacterial drugs target Strep pyogenes or Staph aureus
• Infections include: folliculitis, impetigo, furuncles, carbuncles, cellulitis, pustules, vesicles, papules
• Examples of antibacterial drugs include: bacitracin, neomycin, polymyxin, neomycin and polymyxin B (Neosporin), mupirocin (Bactroban) and silver sulfadiazine (Flamazene®)

Antiacne Meds

• Some antiacne medications include: benzoyl peroxide, clindamycin topicals, isotretinoin (Accutane) and tretinoin (retinoic acid)

Topical Fungal Infections

• Topical fungal infections are difficult to eradicate and therapy may be prolonged for weeks to a year
• Causes of topical fungal infections include: candida albicans, dermatophytes, and malassezia furfur
• Clotrimazole OTC is safe during pregnancy

Topical Antifungal Drug Examples

• Clotrimazole (Canesten®) has many topical formulations - the vaginal version is often used for yeast
• Miconazole nitrate (Micantin®, Micozole®, Monistat®) is a topical cream, is in prefilled applicators or suppository as ovules, and will treat athletes foot, "jock itch," and yeast infections

Topical Antiviral Drugs

• Acyclovir (Zovirax®) can treat initial and recurrent herpes simplex 1 and 2 and human papillomavirus infections
• Topical antivirals do not cure viral skin infections but may reduce healing time and pain
• Common adverse effects are stinging, itching, and rash

Topical Anaesthetic Medications

• Topical anaesthetic medications will reduce: Insect bites, Sunburn, Poison ivy exposure.
• Can also numb the skin before a painful injection
• Topical anaesthetics come in the form of: Ointments, creams, sprays, liquids, jellies
• Examples include EMLA®: lidocaine and prilocaine combination and Betacaine®, Lidodan®

Topical Antipruritic Drugs

• Topical Antipruritic Drugs include:
  • Antihistamines
  • Corticosteroids for their Anti-inflammatory, antipruritic and vasoconstrictive actions

Wound Care Drugs

• Wound care drugs include Vitamin C and zinc when taken orally and sodium hypochlorite (bleach solution, Dakin's solution)
• Other wound care drugs are iodine (Locidedosorb®), collagenase (Santyl®) and acetic acid (vinegar)

Skin Preparation Drugs

• Isopropyl alcohol (70%) causes excessive drying
• Povidone-iodine (Betadine®) reverses granulation
• Chlorhexidine (Dexidin®, Hibitane®) can be CNS toxic to newborns
• Benzalkonium chloride (Agentquat®) can cause chemical burns if left long

Nursing Implications for Topical Drugs

• Wear gloves when applying topical medications
• Apply dressings (e.g., wet, wet-to-dry, occlusive) as prescribed
• Documenting topical medications includes site of application
• Documentation should also include drainage (colour, amount), swelling, temperature and odour, colour, pain, or other sensations
• Document the treatment given and the patient’s response

Structures of the Eye

• Structures that surround the eye includes eyebrows, eyelids, eyelashes plus the Palpebral fissure: space between upper and lower lids when eyes are open but relaxed
• The anterior eye is covered by three layers: Protecive external layer (cornea and sclera), Vascular middle layer called uvea which includes choroid, iris, ciliary body and Internal layer (retina)
• The rest of the structure is composed of conjunctiva, iris, pupil, medial canthus, lacrimal and lateral canthus

Interior of the Eyeball

• Contains anterior and posterior chambers plus Canal of Schlemm
• Other parts are aqueous humour, vitreous humour and the retina
• The retina includes rods, cones and the optic nerve

Nervous System Control of Pupil Size

• Circular smooth muscle reacts with Sphincter muscle to Decreases pupil size (miosis) under Parasympathetic reaction
• Radial smooth muscle reacts with Dilator muscle to increase pupil size (mydriasis) using Sympathetic action

Ocular Drugs and their action

• Mydriatics (apraclonidine) dilates the pupil
• Miotics (acetylcholine, pilocarpine) constricts the pupil
• Cycloplegics (atropine sulphate, cyclopentolate) paralyzes the ciliary body and will have mydriatic properties

Ocular Drug Classes

• Mydriatics dilate the pupil
• Miotics constrict the pupil
• Cycloplegics paralyze the ciliary body

Ocular Drugs

• Ocular Drug classes include: antiglaucoma drugs, antimicrobial drugs, anti-inflammatory drugs, topical anesthetics, diagnostic drugs, antiallergic drugs and lubricants and moisturizers

Glaucoma

• Occurs due to inhibition of the normal flow and drainage of aqueous humour

• Leads to increased intraocular pressure (IOP)

• Pressure against the retina destroys neurons, leading to impaired vision and eventual blindness

• Glaucoma has a range of types, including Closed-angle (acute) and Open-angle (chronic)

• Also characterised by underlying cause: primary, secondary and congenital

• Increased aqueous humour will increase the IOP causing pressure to the retina which impairs vision

• Drugs to reduce IOP include cholinergics: ↑ drainage and adrenergics: mydriatics and sympathomimetics ↑ drainage with decreased production

• Anti-adrenergics or B-blockers (↑ drainage ↓ production)

• Carbonic anhydrase inhibitors (↓ production) plus Osmotic diuretics (↑ drainage) & Prostaglandin agonists (↑ drainage)

Ocular Antimicrobial Drugs have:

• Antibacterial, antiviral and antifungal features that are usually transient and local inflammation
• The use of ophthalmic antibiotics combined with corticosteroids may make it more difficult to rid the eye of any infection
• Antiviral drugs like trifluridine (Viroptic1% ophthalmic drops) will be used for ocular infections such as keratitis and keratoconjunctivitis caused by types 1 and 2 of the herpes simplex virus
• Adverse effects include: secondary glaucoma, corneal punctate defects, uveitis, and stromal edema

Ocular Anti-inflammatory Drugs

• Nonsteroidal anti-inflammatory drugs (NSAIDs) are ketorolac tromethamine (Acular®) flurbiprofen sodium (Ocufen®) and diclofenac sodium (Voltaren®, Ophtha®)
• Corticosteroid Examples Include: dexamethasone (AK Dex®, Doidex®, Dioptrol®, Maxidex®) and fluorometholone (Flarex®, FML®)

Other Ocular Drugs

• Contain Antihistamines, Mast cell stabilizers (cromolyn sodium), Decongestants (Visine) and Lubricants (artificial tears)
• Nursing Implications of administering Ocular drugs:
  • Assess eye first and apply to conjunctival sac with pressure to the inner canthus after application
  • Do not touch the eye with the applicator and be aware that the concurrent use of prostaglandin agonists with other drops cause precipitate so they must be separated by 5 minutes.

Ear Disorders

• Bacterial and fungal infections leads to Inflammatory disorders that cause pain which can lead to earwax accumulation that affects the external ear.

• Physical trauma, dermatitis, seborrhea or psoriasis can also trigger infections but there is also direct instances where : Otitis externa and Otitis media will take hold.

• Otitis Media is common in children <2 with symptoms like Pain, fever, malaise, pressure, fullness and impaired hearing.

• Persistent, recurrent infections may cause tinnitus, nausea, vertigo, mastoiditis to the point that hearing loss may occur.

• With Otitis Media, if afebrile, there will be no treatment for it, leading to a spontaneous resolution

• If febrile, amoxicillin is often the first line of treatment

Otic Drugs

• Otic drug categories include: Antibacterials, antifungals and anti-inflammatories plus Local analgesics and anesthetics, corticosteroids and wax emulsifiers

• Antibacterial and Antifungal otic drugs are typically topical formulations applied to the external ear that may be combined with steroids for anti-inflammatory, antipruritic, and antiallergic drug effects.

• Middle ear infections may require systemic antibiotics

• Antibiotics include neomycin and polymyxin B plus hydrocortisone combination such as AK-Spor HC Otic® that come as a suspension. plus the drops, ciprofloxacin hydrochloride 0.3% (Ciprodex®) and the solution, clioquinol 1% (Locacorten Vioform®)

• Clioquinol (Locacorten Vioform) is considered an Antifungal and an ear drop

Earwax Emulsifiers

• Carbamide peroxide (Murine Ear Wax Removal System Otic®) is combined with others like glycerin, to loosen and help remove cerumen
• Keep in mind that ear canal irrigation with warm water may be needed to assist treatment

Otic Drug Nursing Implications

• Before starting a treatment, Assess baseline hearing or auditory status and Evaluate the patient's symptoms.

• Note that a perforated eardrum may be a contraindication to these drugs with certain exceptions: ciprofloxacin and dexamethasone can be used with perforated eardrums

• The need to remove cerumen before treatment lies with whether there are any perforations and is based on instilling ear drops or being ordered removal by irrigation

• Allow refrigerated solutions to warm to room temperature beforehand

• Knowing that cold ear drops may cause vomiting and dizziness is key to administering the correct procedure

• Administering ear drops depends if the subject is an adult or a child

• Adults: Hold the pinna up and back

• Children younger than 3 years: Hold the pinna down and back