Summary

This document is a study guide on pharmacology, covering topics like pharmacokinetics, medical abbreviations, first-pass metabolism, and properties of ophthalmic preparations. It also includes sections on prescription components, immunoglobulins, and instilling eye drops in children, among other concepts.

Full Transcript

Study Guide Pharmacokinetics Definition: The study of how a drug moves through the body, including absorption, distribution, metabolism, and excretion. Medical Abbreviations ac: Before meals pc: After meals po: By mouth...

Study Guide Pharmacokinetics Definition: The study of how a drug moves through the body, including absorption, distribution, metabolism, and excretion. Medical Abbreviations ac: Before meals pc: After meals po: By mouth qd: Once daily qod: Every other day prn: As needed qid: Four times a day ou: Both eyes od: Right eye os (ol): Left eye I.V.: Intravenous I.D.: Intradermal S.C.: Subcutaneous First-Pass Metabolism Definition: The metabolism of a drug that occurs after oral administration but before it reaches systemic circulation. Primary Organ: The liver. Properties of Ophthalmic Preparations 1. Solutions: Completely dissolved drugs. Easy to instill but short contact time. 2. Suspensions: Contains undissolved particles. Requires shaking before use. 3. Ointments (Ungs): Thick, greasy, and long-lasting lubrication. Can blur vision temporarily. Prescription Components Superscription: The “Rx” symbol at the beginning of a prescription. Inscription: Lists the drug name, strength, and form. Subscription: Instructions for the pharmacist (e.g., quantity to dispense). Signature (Sig): Instructions for the patient (e.g., dosing, route). Mitte: The total amount to dispense. Immunoglobulins (Antibodies) IgG: Responds later in infections, provides long-term immunity. IgM: First responder during initial infection. IgE: Involved in allergic reactions. IgA: Protects mucosal surfaces (e.g., eyes, respiratory tract). Instilling Eye Drops in Children 1. Position the child lying down or reclined. 2. Gently pull down the lower eyelid to create a pocket. 3. Drop the medication in without touching the eye or lashes. 4. Distract or comfort the child to ease anxiety. Routes of Administration – Common Adverse Effects (AEs) 1. Oral (po): GI upset, systemic side effects. 2. Topical (e.g., eye drops): Local irritation, stinging, redness. 3. Intravenous (I.V.): Risk of infection, phlebitis. 4. Subcutaneous (S.C.): Pain or redness at injection site. OTC Labeling Requirements Must include: 1. Brand and generic names. 2. Therapeutic use. 3. Dosage instructions. 4. Side effects (SEs). 5. Contraindications and warnings. Pr vs. OTC Eye Preparations for Allergic Reactions Prescription (Rx): Stronger medications, often include corticosteroids or stronger antihistamines. OTC: Mild antihistamines or decongestants, e.g., ketotifen. NAAION vs. AAION NAAION: Non-Arteritic Anterior Ischemic Optic Neuropathy Sudden, painless vision loss due to reduced blood flow without inflammation. AAION: Arteritic Anterior Ischemic Optic Neuropathy Associated with giant cell arteritis (inflammation of blood vessels). Requires urgent treatment with corticosteroids. NPDR – Non-Proliferative Diabetic Retinopathy Definition: Early stage of diabetic retinopathy characterized by microaneurysms, hemorrhages, and retinal swelling. Study Guide Sympathetic Nervous System (SNS) What? Part of the autonomic nervous system responsible for the “fight or flight” response. Phrase: “Fight, flight, or freeze.” Effects: Pupils: Dilate (mydriasis). Heart rate (HR): Increases. Respiratory rate (Resp): Increases. GI (Saliva & Motility): Decreased saliva production, reduced GI motility. Rs (Sweat glands): Increased sweating. Pseudodendrite Meaning: A lesion resembling a dendrite but caused by conditions like herpes zoster ophthalmicus (HZO), not herpes simplex virus (HSV). Treatment: Antivirals (e.g., acyclovir, valacyclovir). Lubricants for corneal healing. Corticosteroids (if inflammation is significant). Peripheral Iridotomy Surgery Meaning: A laser or surgical procedure to create a hole in the iris to improve aqueous humor drainage. Treatment for: Narrow-angle or angle-closure glaucoma. Meibomian Gland Dysfunction (MGD) Meaning: Chronic blockage or inflammation of the meibomian glands, leading to poor tear film quality. Treatment: Warm compresses. Lid massage and hygiene. Artificial tears (lipid-based). Oral doxycycline (for severe cases). Internal Hordeolum Meaning: An infection or inflammation of the meibomian glands inside the eyelid. Treatment: Warm compresses. Antibiotics (topical or oral, e.g., doxycycline). Incision and drainage if persistent. Autoimmune Diseases 1. Myasthenia Gravis (MG): Effect: Neuromuscular junction (muscle weakness, ptosis, diplopia). Cause: Autoantibodies against acetylcholine receptors. 2. Grave’s Disease: Effect: Thyroid gland (hyperthyroidism, exophthalmos, lid retraction). Cause: Autoantibodies stimulate thyroid hormone production. 3. Rheumatoid Arthritis (RA): Effect: Joints (pain, swelling, deformity), sometimes eyes (scleritis). 4. Multiple Sclerosis (MS): Effect: Central nervous system (CNS), leading to demyelination. 5. Giant Cell Arteritis (GCA): Effect: Blood vessels (especially temporal arteries), can cause ischemic optic neuropathy. HbA1c Test Measures: Average blood sugar levels over 2-3 months. Disease: Diabetes mellitus. Normal Range: Below 5.7%. Diabetic Range: 6.5% or higher. Scleritis What is it? Inflammation of the sclera (often painful and severe). Common Causes: Autoimmune diseases (e.g., RA, lupus). Anterior Uveitis What is it? Inflammation of the anterior uvea (iris and ciliary body). Common Causes: Autoimmune diseases (e.g., ankylosing spondylitis, sarcoidosis). Infectious diseases (e.g., herpes, syphilis). Munson’s Sign What is it? A V-shaped indentation of the lower eyelid when the patient looks down. Disease: Keratoconus (corneal thinning and bulging). RAPD (Relative Afferent Pupillary Defect) Pupil Reaction: Affected eye shows reduced or no constriction when exposed to light during a swinging flashlight test. Causes: Optic nerve damage (e.g., optic neuritis, ischemic optic neuropathy). Severe retinal disease. Diseases Associated with Lack of Sweat (Unilateral Facial Anhidrosis) Conditions: Horner’s Syndrome. Autonomic nerve damage. Nystagmus What is it? Involuntary, rhythmic eye movements (side-to-side, up-down, or circular). Causes: Congenital (present at birth). Neurological conditions (e.g., MS, brainstem lesions). Inner ear disorders (e.g., vestibular dysfunction). Branch Retinal Artery Occlusion (BRAO) Causes: 1. Emboli (most common): Cholesterol emboli (from carotid artery atherosclerosis). Calcific emboli (from cardiac valves). Fibrin-platelet emboli (from heart or arteries). 2. Atherosclerosis: Narrowing of retinal arteries due to plaque buildup. 3. Cardiovascular Conditions: Arrhythmias (e.g., atrial fibrillation). Heart valve diseases or prosthetic valves. 4. Hypercoagulable States: Blood clotting disorders (e.g., Factor V Leiden, antiphospholipid syndrome). 5. Inflammatory or Vasculitic Conditions: Giant cell arteritis. Systemic lupus erythematosus. 6. Trauma: Blunt or penetrating ocular trauma. 7. Other Causes: Migraines with vasospasm. Rarely, systemic infections or drug-induced vasospasm (e.g., from oral contraceptives). Risk Factors: Hypertension. Diabetes mellitus. Smoking. Hyperlipidemia. Older age. Mechanism: BRAO occurs when blood flow to a branch of the central retinal artery is blocked, leading to ischemia in the area supplied by that branch. This results in sudden, painless, partial vision loss. Study Guide: MOA & Therapeutic Use 1. Phenylephrine MOA: Alpha-1 adrenergic agonist; causes vasoconstriction and pupillary dilation by stimulating the iris dilator muscle. Therapeutic Use: Pupil dilation (mydriasis) for diagnostic exams; reduces conjunctival redness. 2. Brimonidine MOA: Alpha-2 adrenergic agonist; decreases aqueous humor production and increases uveoscleral outflow. Therapeutic Use: Lowers intraocular pressure (IOP) in glaucoma or ocular hypertension. 3. Dapiprazole MOA: Alpha-adrenergic antagonist; reverses pupillary dilation by inhibiting the iris dilator muscle. Therapeutic Use: Reversal of pharmacologically induced mydriasis. 4. Timolol MOA: Non-selective beta-blocker; decreases aqueous humor production in the ciliary body. Therapeutic Use: Lowers IOP in glaucoma or ocular hypertension. 5. Latanoprost MOA: Prostaglandin analog; increases uveoscleral outflow of aqueous humor. Therapeutic Use: Reduces IOP in open-angle glaucoma or ocular hypertension. 6. Cyclopentolate MOA: Anticholinergic; blocks parasympathetic stimulation of the iris sphincter and ciliary muscle, causing mydriasis and cycloplegia. Therapeutic Use: Pupil dilation and paralysis of accommodation for diagnostic exams. 7. Erythromycin MOA: Macrolide antibiotic; inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. Therapeutic Use: Treatment of bacterial conjunctivitis and prophylaxis in neonates. 8. Proparacaine MOA: Topical anesthetic; blocks sodium channels, preventing nerve signal transmission. Therapeutic Use: Provides local anesthesia for minor procedures or diagnostic testing. 9. Tropicamide MOA: Anticholinergic; blocks parasympathetic input to the iris sphincter and ciliary muscle, causing mydriasis and cycloplegia. Therapeutic Use: Pupil dilation for fundus exams. 10. Homatropine MOA: Anticholinergic; produces mydriasis and cycloplegia by blocking parasympathetic stimulation. Therapeutic Use: Treats anterior uveitis by relieving pain and preventing synechiae. 11. Atropine MOA: Anticholinergic; inhibits parasympathetic input to the iris sphincter and ciliary muscle, causing prolonged mydriasis and cycloplegia. Duration of Action: Up to 7-14 days. Therapeutic Use: Uveitis, amblyopia therapy, and diagnostic use requiring long-lasting effects. 12. Tobramycin MOA: Aminoglycoside antibiotic; inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit. Therapeutic Use: Treats bacterial conjunctivitis and keratitis. 13. Sulphacetamide MOA: Sulfonamide antibiotic; inhibits bacterial folic acid synthesis by targeting dihydropteroate synthase. Therapeutic Use: Treats bacterial conjunctivitis. 14. Ciprofloxacin MOA: Fluoroquinolone antibiotic; inhibits bacterial DNA gyrase and topoisomerase IV. Therapeutic Use: Treats bacterial conjunctivitis and corneal ulcers. 15. Ketorolac MOA: Non-steroidal anti-inflammatory drug (NSAID); inhibits cyclooxygenase (COX), reducing prostaglandin synthesis. Therapeutic Use: Treats postoperative inflammation and allergic conjunctivitis. 16. Diclofenac MOA: NSAID; inhibits COX enzymes to reduce inflammation and pain. Therapeutic Use: Postoperative inflammation, corneal abrasions. 17. Dipivefrin MOA: Prodrug of epinephrine; decreases IOP by reducing aqueous humor production and increasing outflow. Therapeutic Use: Glaucoma management. 18. Bromfenac MOA: NSAID; inhibits COX enzymes to reduce inflammation and pain. Therapeutic Use: Postoperative inflammation and pain relief. 19. Anti-VEGF Injections Examples: Ranibizumab (Lucentis®), Aflibercept (Eylea®), Bevacizumab (Avastin®). MOA: Inhibit vascular endothelial growth factor (VEGF) to reduce abnormal blood vessel growth and leakage. Therapeutic Use: Treats wet age-related macular degeneration (AMD), diabetic macular edema (DME). 20. Botox® (Botulinum Toxin) MOA: Blocks acetylcholine release at neuromuscular junctions, causing temporary muscle paralysis. Therapeutic Use: Treats blepharospasm, strabismus, and cosmetic indications. 21. Retrobulbar Injection MOA: Injection of anesthetic or therapeutic agents into the retrobulbar space. Therapeutic Use: Provides anesthesia for ocular surgery or delivers medication for certain diseases. 22. Lissamine Green MOA: Stains devitalized or damaged epithelial cells and mucus. Therapeutic Use: Diagnoses dry eye disease and evaluates conjunctival damage. 23. Fluorescein MOA: Stains areas of corneal epithelial loss or breaks in the tear film. Therapeutic Use: Detects corneal abrasions, ulcers, and evaluates tear film integrity. 24. Rose Bengal MOA: Stains damaged or devitalized epithelial cells and mucus. Therapeutic Use: Diagnoses keratoconjunctivitis sicca (dry eye) and herpetic keratitis. 25. Trypan Blue MOA: Stains the anterior capsule of the lens for better visualization during surgery. Therapeutic Use: Assists in cataract surgery (capsule staining). Study Guide Medical Devices and Implants ReSure® What is it? A hydrogel ocular sealant applied after cataract or other anterior segment surgeries to seal corneal incisions and prevent wound leaks. Uses: Provides a temporary seal for self-healing wounds in the cornea. Prokera® What is it? A therapeutic device containing an amniotic membrane graft within a ring, placed on the eye like a contact lens. Uses: Treats ocular surface disorders (e.g., severe dry eye, corneal ulcers, chemical burns, inflammation). The amniotic membrane promotes healing and reduces inflammation. Retisert® What is it? A corticosteroid (fluocinolone acetonide) intravitreal implant surgically inserted into the vitreous cavity. Uses: Long-term treatment of chronic, non-infectious posterior uveitis. Medications Methotrexate (MTX) Uses in Eye Treatment: Treats autoimmune uveitis. Manages ocular inflammatory diseases like scleritis. MOA: Inhibits dihydrofolate reductase, reducing inflammation by interfering with DNA synthesis and immune cell proliferation. Contact Lens Solutions ClearCare® Properties: Hydrogen peroxide-based cleaning and disinfecting solution. Uses: Deep cleans and disinfects soft and rigid gas-permeable (RGP) lenses; requires a neutralizing case to convert peroxide to saline before use. Boston Simplus® Properties: One-step cleaner and conditioner for RGP lenses. Uses: Removes debris, conditions lenses for comfort, and disinfects. Boston Advance® Properties: Two-step cleaning and conditioning system for RGP lenses. Uses: Provides deep cleaning and storage conditioning for optimal lens performance. Cycloplegics What do they do? Temporarily paralyze the ciliary muscle and iris sphincter muscle. Effects on Eye: 1. Mydriasis (pupil dilation). 2. Cycloplegia (paralysis of accommodation, preventing focusing on near objects). Uses: Diagnostic exams, treating anterior uveitis (reduces pain and prevents synechiae). Medication Effects on the Eye 1. Hydroxychloroquine (Plaquenil®): Effects: Retinal toxicity (bull’s-eye maculopathy), corneal deposits. Uses: Treats autoimmune conditions (e.g., RA, lupus). 2. Isotretinoin (Accutane®): Effects: Dry eye, meibomian gland dysfunction, night vision disturbances. Uses: Treats severe acne. 3. Tamsulosin (Flomax®): Effects: Intraoperative floppy iris syndrome (IFIS) during cataract surgery. Uses: Treats benign prostatic hyperplasia (BPH). 4. Minocycline: Effects: Pigmented conjunctiva, sclera, or eyelids; pseudotumor cerebri (intracranial hypertension). Uses: Treats acne and bacterial infections. 5. Amiodarone: Effects: Corneal deposits (verticillata), optic neuropathy. Uses: Treats cardiac arrhythmias. 6. Corticosteroids: Effects: Elevated IOP (steroid-induced glaucoma), posterior subcapsular cataracts, delayed wound healing. Uses: Treats inflammation (e.g., uveitis, scleritis). 7. Sildenafil (Viagra®): Effects: Visual disturbances (blue-tinged vision, light sensitivity), NAION (rare). Uses: Treats erectile dysfunction and pulmonary hypertension. 8. Alendronate (Fosamax®): Effects: Scleritis, conjunctivitis. Uses: Treats osteoporosis. 9. Tamoxifen: Effects: Retinopathy (crystalline maculopathy), corneal deposits. Uses: Treats breast cancer and reduces recurrence risk.

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