Autacoids Flashcards
(40 cards)
H1 Receptors
Type
Location
Action
- Gq-coupled. Nerves, smooth muscle, bronchi, intestines.
- Causes vasodilation, capillary permeability (edema, hives), bronchoconstriction, pain, itch, and intestinal smooth muscle contraction.
H2 Receptors
Type
Location
Action
- Gs-coupled. Gastric mucosa, heart, and mast cells.
- Vasodilation, increased HR via reflex tachycardia (due to decreased baroreceptor firing following vasodilation) and direct stimulation, gastric acid secretion.
H3 Receptors
Type
Location
Action
Gi-coupled (inhibitory). Autoreceptors on histaminergic neurons.
H4 receptors
Type
Location
Gi-coupled. Eosinophils, neutrophils, CD4 T cells.
Diphenhydramine Brand Name Generation Receptor Tx Adverse Effects Precautions
Benadryl, Sominex
• 1st generation. H1 inverse agonist
• Tx allergic rhinitis, sneezing, itching, urticaria, insomnia (produces sedation).
• Antimuscarinic (Ach) activity – treats motion sickness (NV, vertigo). Also has antiparkinsonian effects.
Adverse Effects
• CNS: confusion, dizziness, sedation
• Antimuscarinic effects: mydriasis (pupil dilation), xerostomia (dry mouth), reduced bronchial secretions, tachycardia, constipation, urinary retention
• Avoid in people w/ glaucoma due to mydriasis.
• Greatly metabolized by 2D6. Avoid in people w/ hepatic disease.
Cetirizine Brand Name Generation Receptor Tx Adverse Rxns Precautions
Zyrtec 2nd generation. H1 inverse agonist. • Tx allergic conditions • Less sedating than 1st gen. • Minimal antimuscarinic activity • Few adverse rxns. Xerostomia. • Do not exceed 5 mg / day if CrCL less than 31 mL / min.
Fexofenadine Brand Name Generation Receptor Tx Adverse Effects Precautions
Allegra 2nd generation. H1 inverse agonist. • Tx allergic conditions • No antimuscarinic effects • Few adverse rxns. • Avoid taking w/ fruit juices due to decreased absorption
Loratadine Brand Name Generation Receptor Tx Adverse Effects
Claritin 2nd generation. H1 inverse agonist. • Tx allergic conditions • Little / no antimuscarinic activity • Few adverse rxns.
Cimetidine
Receptor
Tx
Adverse Effects
H2 inverse agonist
• Tx for peptic ulcer disease, GERD, and dyspepsia (indigestion)
• May cause moderate / severe headaches and rare blood dyscrasia (neutropenia, leukopenia, etc)
Ergotamine Receptor Mechanism Tx Adverse Rxns Precautions
Serotonin partial agonist / antagonist. Causes vasoconstriction.
• Tx migraines
• Oxytocic agent → uterine contractions. Decreases postpartum bleeding via constriction.
• Metabolized by 3A4
Adverse rxns: NVD, xerostomia
• Ergotism: angina, asthenia, coronary vasospasm, cramps, myalgia, paresthesias, changes in HR; vasoconstriction may result in hypothermia or tissue necrosis
Precautions – avoid when vasoconstriction would cause problems
• CV: angina, arteriosclerosis, coronary artery disease, hypertension, peripheral vascular disease, Raynaud’s disease, thrombophlebitis, MI, stroke
• Hepatic disease, biliary tract disease, cholestasis
• Renal failure or impairment
• FDA Pregnancy Risk Category X (due to labor induction)
Sumatriptan Receptor Tx Adverse Rxns Precautions
Agonist at 5HT-1D autoreceptors (system inhibition) and 5HT-1B → vasoconstriction
• Tx migraines. Not for prophylaxis.
Adverse rxns
• Fatal CV events (coronary artery vasospasm, arrhythmias, MI)
• GI: NVD, vasospasm → bowel ischemia, abdominal pain, bloody diarrhea
Precautions – again, sxs that vasoconstriction would exacerbate.
• CV: angina, arteriosclerosis, arrhythmias, coronary artery disease, hypertension, peripheral vascular disease, Raynaud’s disease, thrombophlebitis, MI, stroke; evaluate CV function before prescribing
• Ischemic bowel disease
Thromboxane (TXA2)
Vasoconstriction and platelet aggregation. TP receptors.
Prostacyclin (PGI2)
Vasodilation and inhibited platelet aggregation. Physical antagonist of thromboxane. IP receptors.
PGD2
Smooth muscle contraction and inhibited platelet aggregation. DP receptors.
PGE2
Vasodilation, pain, fever, diuresis, immunomodulation. EP receptors.
PGF-a
Smooth muscle contraction: vasoconstriction, bronchoconstriction, uterine contraction. FP receptors.
LTB4 Released by Target Action Receptors
Released by and acts on neutrophils (autoregulation). → plasma exudation. BLT1 and BLT2 receptors.
Cysteinyl Leukotrienes Types Released by Action Receptors
Include LTC4, LTD4, and LTE4 – released by mast cells, basophils, and eosinophils. → bronchoconstriction, vasoconstriction, decreased blood flow, decreased contractility, and plasma exudation. CysLT1 and CysLT2 receptors.
Lipoxins
Types
Receptor
Action
LXA4 and LXB4 bind ALX receptors. Antagonize effects of leukotrienes (cause relaxation). Competitively inhibit CysLT1 receptors.
Systemic effects of cortisol
Stimulates GNG, immunosuppressive / anti-inflammatory effects. Also increased blood glucose and insulin, lipolysis and lipogenesis, stimulates protein / bone catabolism
Anti-inflammatory effects of corticosteroids
Increases?
Decreases?
- Increases: annexin 1 (inhibits PLA2), SLPI (secretory leukoprotease inhibitor), IL-10 (inhibits cytokines), and NFkB-inhibitor (nuclear factor kB, activates immune system).
- Decreases: COX-2, cytokines (IL-1, 2), chemokines (IL-8), CAMs, inflammatory enzymes
Hydrocortisone Action Tx Adverse Effects Precautions
Natural steroid hormone. Inhibits COX-2 expression, decreases cytokines, induces apoptosis of eosinophils.
• Tx anti-inflammatory: anaphylaxis, asthma, COPD, IBD, rheumatism, dermatoses
• DOC for glucocorticoid replacement therapy
• No adverse rxns w/ acute use. Prolonged use may result in dependence due to HPA suppression → hyperglycemia, immunosuppression, cataracts, glaucoma
• Precautions – abrupt DC of prolonged systemic therapy and Cushing’s Syndrome
Prednisone Action Tx Metabolism Adverse Rxns Precautions
Represses COX-2 expression, decreases cytokines, apoptosis of eosinophils
• Tx for autoimmune disorders (asthma, IBD, rheumatoid) and allograft rejection
• Prodrug of prenisolone (active)
Adverse Rxns
• CNS: headache, insomnia, vertigo, depression, anxiety, euphoria, personality changes, psychosis
• GI: NVD, anorexia, gastritis
• Cataracts
• Opportunistic infections (thrush, fungal infection in oral cavity due to immunosuppresion)
Precautions – Cushing’s, abrupt DC of prolonged therapy, cataracts
Fluticasone Mechanism Tx Adverse effects Precautions
Medium potency – same mechanism as others.
• Tx for dermatoses (psoriasis), allergic / nonallergic rhinitis, and asthma prevention only.
• Adverse effects: pruritis, burning, hypertrichosis (hair overgrowth), hoarseness, irritation, 2ndary infections (thrush)
• Precautions – Cushing’s, avoid DC for prolonged use, cataracts