Pharm Study guide questions E2 (copy)

What are the most likely respective Types of DM in dogs and cats?

Dogs: Type 1 (lack of insulin); Cats: Type 2 (lack of response to insulin)

What are the two goals of DM treatment in dogs?

Eliminate clinical signs and improve comfort; prevent short-term complications such as DKA and hypoglycemia

What is the primary goal of DM treatment in cats?

Remission

What is the difference between amorphous and crystalline insulin?

Amorphous: insulin molecules uncoordinated and rapidly absorbed; Crystalline: coordinated crystals that slow absorption

How do protamine, zinc, and myristic acid alter insulin absorption?

Protamine crystallizes insulin to slow absorption; Zinc forms hexamers to slow absorption; Myristic acid binds albumin so insulin releases slowly

What is the short-acting insulin used in veterinary medicine and when do you use it?

Regular insulin used IV or IM for hyperglycemic crises such as DKA

What are the starting drugs for dogs?

Intermediate-acting insulins

What intermediate-acting insulin is sometimes referred to as Lente?

Vetsulin (a zinc preparation)

What is important about matching insulin syringes?

Match syringe type to insulin concentration (40 U/mL vs 100 U/mL)

What is important about Vetsulin?

Must be shaken before use

What are the five long-acting insulins?

Ultralente; PZI; Glargine; Detemir; Degludec

What are the unusual solubility characteristics of glargine and how does this impact dilutability?

Low pH makes it soluble in vial; precipitates after injection for slow release; should not be diluted casually

What is the caveat about using Detemir in dogs?

Human formulation is 4× concentrated leading to increased hypoglycemia risk

Why is relying on clinical signs not absolute for avoiding hypoglycemia in cats on long-acting insulin?

Cats may have hypoglycemia without clinical signs

What are the current insulin recommendations for diabetic dogs and cats?

Dogs: NPH or Vetsulin; Cats: Glargine or Detemir or PZI

What is the ultimate therapeutic goal for diabetic cats?

Remission

Why is hypoglycemia especially concerning in pets?

It is life-threatening and pets cannot readily self-correct with snacks

What is the Somogyi effect?

Rebound hyperglycemia caused by insulin overdose leading to rapid hypoglycemia followed by compensatory glucose release

How do you detect the Somogyi effect and what do you do?

Dogs: BG curve; Cats: fructosamine; Reduce insulin dose and recheck in 2-5 days

Why does acromegaly or sexual intactness complicate diabetes treatment?

Acromegaly causes severe insulin resistance; Intact animals may have underlying disease or hormone effects causing poor regulation

Explain why renal disease may impact diabetes treatment.

Kidneys clear insulin so renal disease prolongs insulin duration; intermediate-acting insulin may last longer

What is used to treat DKA?

Regular insulin via IV CRI or intermittent IM

When are non-insulin diabetes drugs used?

Cats whose owners refuse insulin; adjunct for refractory diabetic dogs; post-remission cats needing diet support

What drug has many uses in endocrine pharmacology?

Bromocriptine

If a diabetic dog shows the Somogyi effect on Vetsulin, what insulin is the next choice?

PZI because it has longer duration; use same unit dose and repeat BG curve in 1 week

Why are prandially administered non-insulin drugs not recommended in cats?

They are generally ineffective and not recommended

Why is zinc additionally important in diabetes?

Zinc crystallizes insulin into hexamers slowing absorption

How is insulin used in bovine and equine DM-like diseases?

Cattle ketosis: severe cases use PZI every other day with IV glucose; Fat cow ketosis: NPH twice daily with IV glucose; Equine metabolic syndrome: insulin not primary treatment

What is streptozotocin and when is it used?

Alkylating agent toxic to DNA; selectively kills pancreatic islet cells via GLUT2; used to treat insulinomas

How does the hypothalamus and anterior pituitary promote and regulate the synthesis of thyroid hormones?

TRH from hypothalamus stimulates TSH release; TSH stimulates T3, T4, and calcitonin synthesis and release; TSH increases NIS expression and thyroglobulin synthesis; T3 and T4 provide negative feedback on TRH and TSH

What are the synthesis mechanisms for thyroid hormones?

Iodine enters thyroid via NIS; tyrosine on thyroglobulin is iodinated to MIT and DIT; TG is iodinated in follicle lumen; iodinated TG is endocytosed; proteolysis releases MIT and DIT; coupling MIT+DIT → T3; DIT+DIT → T4

What are the release mechanisms for thyroid hormones?

TSH promotes release of T3 and T4 from follicular cells into plasma

Name three drugs that can cause pseudohypothyroidism.

Glucocorticoids; phenobarbital; sulfonamide antibiotics

What is the treatment for hypothyroidism in dogs?

T4 supplementation (levothyroxine) is gold standard

What is the treatment for hypothyroidism in cats?

T4 supplementation for iatrogenic or congenital disease

What is the treatment for hypothyroidism in horses?

T4 supplementation possible though true hypothyroidism is rare; sometimes used for weight loss in EMS

What are the treatments for hyperthyroidism in the cat?

Low-iodine Y/D diet; methimazole inhibits thyroperoxidase; I-131 radiolysis; thyroidectomy after methimazole pretreatment

What is the treatment for hypoparathyroidism?

Oral calcium lactate or carbonate plus calcitriol

What is the treatment for milk fever?

IV calcium borogluconate

What is the major NT of the PNS?

Acetylcholine

What are the major effector NTs of the SNS at the organ or tissue?

Norepinephrine; epinephrine

What NT is common to the SNS and PNS?

Acetylcholine

What are the seven major receptors of the ANS?

Cholinergic ion channels at SNS/PNS ganglia and NMJ; muscarinic GPCRs post-ganglion; adrenergic receptors α1, α2, β1, β2, β3

If you want to prevent urination, what SNS receptor would you activate and what PNS receptor would you inhibit?

Activate α1 for sphincter contraction; activate β1 to reduce bladder contraction; inhibit muscarinic receptors

If you want to promote urination, what PNS receptor would you activate and what SNS receptor would you inhibit?

Activate muscarinic receptors; inhibit α1 for sphincter relaxation; inhibit β1 to remove inhibition of bladder contraction

If you want to promote mydriasis, what SNS receptor would you activate and what PNS receptor would you inhibit?

Activate α1; inhibit muscarinic receptors

If you want to promote miosis, what PNS receptor would you activate and what SNS receptor would you inhibit?

Activate muscarinic receptors; inhibit α1

What is the MOA and indication for phenylpropanolamine?

α1 and β1 agonist; promotes urine retention

What is the MOA and indication for oxybutynin?

Muscarinic antagonist; promotes urine retention

What is the MOA and indication for prazosin?

α1 antagonist; promotes urination

What is the MOA and indication for tamsulosin?

Selective α1 antagonist; promotes urination; treats urethrospasm

What is the MOA and indication for phenoxybenzamine?

Irreversible α1 antagonist; treats hypertension from pheochromocytoma

What is the MOA and indication for bethanecol?

Muscarinic agonist; promotes urination

What is the MOA and indication for tropicamide?

Muscarinic antagonist; causes mydriasis for ocular exams

What is the MOA and indication for atropine?

Muscarinic antagonist; causes mydriasis; improves comfort in uveitis; prevents posterior synechia; treats AChE inhibitor toxicity

What is the MOA and indication for phenylephrine?

α1 agonist; causes mydriasis

What is the MOA and indication for pilocarpine?

Muscarinic agonist; causes miosis; treats glaucoma and lens instability

What is the MOA and indication for demecarium bromide?

Muscarinic agonist; causes miosis; treats glaucoma and lens instability

What is the MOA and indication for succinylcholine?

nAChR activator not degraded by AChE; causes flaccid paralysis; used in equine castration and wildlife euthanasia

What is the mechanistic goal of drugs addressing CHF?

Increase intra-myocytic calcium to improve contractility

What is the MOA of digoxin?

Inhibits Na/K ATPase; increases intracellular Na; Na/Ca exchanger increases intracellular Ca

What is the MOA of dopamine in CHF?

D1 receptor agonist; activates adenylyl cyclase; increases cAMP; increases Ca

What is the MOA of dobutamine?

β1 receptor agonist; activates adenylyl cyclase; increases cAMP; increases Ca

What is the MOA of amrinone?

PDE3 inhibitor; increases cAMP; increases intracellular Ca

What is the MOA of pimobendan?

PDE3 inhibitor and calcium sensitizer; binds troponin C to increase Ca affinity

Which anti-CHF drug is also a vasodilator?

Pimobendan (inodilator); opens K channels in vascular smooth muscle

Which anti-CHF drug is more likely to cause toxicity in hypokalemic patients?

Digoxin

What is the common toxicity for all anti-CHF drugs?

Arrhythmias

Which two drugs address ventricular ectopic beats and what is their MOA?

Verapamil and diltiazem; voltage-gated Ca channel blockers

Which anti-arrhythmic drug can cause corneal deposits and what is its MOA?

Amiodarone; complex mechanism including K and Ca channel blockade

Which two anti-arrhythmic drugs selectively bind refractory sodium channels?

Lidocaine; mexiletine

What is the preferred long-term oral drug for V-tach and V-arrhythmias and what is its MOA?

Procainamide; class I Na channel blocker with moderate association/dissociation

A cat with hyperthyroidism-mediated arrhythmia should be given which drug and what is its MOA?

Propranolol; β1 antagonist

A cat with hyperthyroidism-mediated hypertension should receive which drug and what is its MOA?

Amlodipine; calcium channel blocker; frontline monotherapy in cats

What is the MOA of hydralazine and why is it only for emergencies?

Inhibits Ca release from SR; increases NO sensitivity; opens K channels causing vasodilation; causes severe hypotension activating baroreflex

What is the other emergency antihypertensive drug and its MOA?

Sodium nitroprusside; donates NO causing NANC vasodilation and hypotension

How does telmisartan address hypertension?

Angiotensin II receptor antagonist; increases NO; causes vasodilation

Name two ACE inhibitors and their mechanism in hypertension.

Enalapril; benazepril; prevent AGI → AGII conversion leading to vasodilation

How do ACE inhibitors assist anti-CHF drugs?

Reduce fluid load and workload on heart

What drug treats pulmonary hypertension and what is its MOA?

Sildenafil; PDE5 inhibitor in vascular smooth muscle

What is the mainstay drug for cardiac resuscitation?

Epinephrine (adrenaline)

What are the three main physiologic facets that control airway tone?

Parasympathetic system causes baseline bronchoconstriction; sympathetic system causes bronchodilation via β2; NANC system causes bronchodilation via nitric oxide

How can airway tone be pharmacologically manipulated to cause bronchodilation?

Block parasympathetic system with anticholinergics; stimulate sympathetic system with β receptor agonists

What are the types, names, and selectivities of β-agonists that cause bronchodilation?

Nonselective β agonists: epinephrine, isoproterenol, ephedrine; Selective β2 agonists: terbutaline, albuterol, clenbuterol

What methylxanthines cause bronchodilation and how do they work?

Theophylline and aminophylline; PDE inhibition increases cAMP causing bronchodilation

What are the issues with clenbuterol in horses and cattle?

Horses: muscle tremors, sweating, tachycardia; high doses activate β1; Cattle: banned feed additive due to repartitioning effects

What are the issues with zilpaterol in horses and cattle?

Horses: highly toxic; Cattle: approved but voluntarily withdrawn due to health concerns

Which anticholinergics cause bronchodilation?

Atropine; ipratropium; glycopyrrolate

What are expectorants?

Increase fluidity of respiratory secretions making them easier to cough out; examples: potassium iodide, ambroxol, guaifenesin

What are peripheral antitussives?

Relieve irritation often via bronchodilation; example: ephedrine

What are central antitussives?

Depress cough center in brain; narcotics: codeine, hydrocodone, butorphanol; non-narcotic: dextromethorphan

What is the action of doxapram?

Respiratory stimulant activating carotid body chemoreceptors to stimulate brainstem respiratory center

What are the uses of doxapram?

Stimulate respiration peri-surgically; reverse opioid-induced respiratory depression

What is the action of thioredoxin?

Protein disulfide reductase; breaks inflammatory proteins on mucosa; activates β-defensins for antimicrobial effects

What is the use of thioredoxin?

Potential nebulized treatment for respiratory infections such as BRD

Which antibiotics are good for BRD metaphylaxis?

Tulathromycin; gamithromycin; tildipirosin; tilmicosin

Which antibiotics are good for BRD treatment?

Florfenicol; ceftiofur; enrofloxacin; danofloxacin

Which antibiotic is good for dairy cattle, swine, and equine respiratory disease?

Ceftiofur

Which antibiotics are good for dogs and cats with respiratory infections?

Amoxicillin with clavulanate

When are diuretic drugs used?

To promote diuresis and reduce circulating volume; commonly used to treat CHF and edema