Veterinary Sulfonamides Administration
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Questions and Answers

What is the main reason for the continued widespread use of sulfonamides in veterinary medicine?

  • Their low cost and relative efficacy in common bacterial diseases (correct)
  • Their broad spectrum of activity against all bacterial diseases
  • Their high cost and wide availability
  • Their minimal side effects and long duration of action

What renders sulfonamides much more effective than sulfonamides alone?

  • Their combination with diaminopyrimidines (correct)
  • Their duration of effect
  • Their lipid solubility
  • Their water solubility

How often are standard-use sulfonamides typically administered in most species to control systemic infections due to susceptible bacteria?

  • Once a week
  • Every 1 to 2 days
  • Every 6 to 24 hours (correct)
  • Every 3 to 4 days

What is the primary use of very water-soluble sulfonamides like sulfisoxazole and sulfasomidine?

<p>To treat urinary tract infections (B)</p> Signup and view all the answers

What is the most common route of administration for therapeutic doses of sulfonamides in monogastric animals?

<p>Oral (PO) (C)</p> Signup and view all the answers

In which animals is the absorption of trimethoprim delayed and tends to be trapped in the ruminoreticulum?

<p>Ruminants (A)</p> Signup and view all the answers

Where are concentrations of sulfadiazine ≥90% bound to plasma proteins?

<p>In the kidneys (B)</p> Signup and view all the answers

Which body fluid may contain 50%–90% of the concentrations of sulfonamides found in blood?

<p>Cerebrospinal fluid (CSF) (B)</p> Signup and view all the answers

Where are trimethoprim and ormetoprim likely to accumulate due to their basic properties?

<p>In acidic urine (D)</p> Signup and view all the answers

What is the distribution pattern of sulfonamides based on?

<p>The ionization state, vascularity of specific tissues, and barriers to diffusion (B)</p> Signup and view all the answers

What is the main route of excretion for trimethoprim?

<p>Urine (B)</p> Signup and view all the answers

Which species shows some suggestion of extensive hepatic biotransformation for trimethoprim?

<p>Ruminants (D)</p> Signup and view all the answers

Where are sulfonamide residues often detected due to passive diffusion?

<p>Milk (A)</p> Signup and view all the answers

Which route of administration greatly decreases the bioavailability of sulfachlorpyridazine?

<p>Oral (PO) (D)</p> Signup and view all the answers

What is the main route of administration for therapeutic doses of sulfonamides when dealing with acute life-threatening infections?

<p>Intravenous (IV) (C)</p> Signup and view all the answers

Which tissue may have concentrations of trimethoprim higher than corresponding plasma concentrations?

<p>Kidneys (D)</p> Signup and view all the answers

What is the effect of sulfonamides on ruminal microflora?

<p>Sulfonamides depress the cellulolytic function of ruminal microflora (C)</p> Signup and view all the answers

What adverse effect has been associated with prolonged sulfonamide treatment in dogs?

<p>Hypothyroidism (A)</p> Signup and view all the answers

How does high-dose trimethoprim treatment affect hematopoiesis?

<p>Promotes maturation defects (A)</p> Signup and view all the answers

What adverse effect is associated with treatment using trimethoprim-sulfamethoxazole in horses?

<p>Immune-mediated hemolytic anemia (D)</p> Signup and view all the answers

Which parameter is increased by sulfonamides according to the text?

<p>Eosinophil count (A)</p> Signup and view all the answers

What is the effect of antacids on the gastrointestinal absorption of sulfonamides?

<p>Inhibits absorption (D)</p> Signup and view all the answers

Which statement about withdrawal times for food-producing animals is true?

<p>Attention to withdrawal times is essential due to adverse effects in people (A)</p> Signup and view all the answers

How does urinary acidification affect sulfonamide excretion?

<p>Reduces sulfonamide excretion (B)</p> Signup and view all the answers

What type of wounds do sulfonamides retard healing of?

<p>Uncontaminated wounds (B)</p> Signup and view all the answers

Which species may experience mild follicular thyroid hyperplasia due to prolonged administration of sulfonamides?

<p>Dogs (D)</p> Signup and view all the answers

What is the potential effect of concurrent administration of acidic drugs with higher binding affinities on sulfonamides?

<p>Decreased plasma-protein binding of sulfonamides (B)</p> Signup and view all the answers

How does alkalinization of urine affect sulfonamide excretion?

<p>Promotes sulfonamide excretion (A)</p> Signup and view all the answers

What is the optimal in vitro ratio for the combination of trimethoprim or ormetoprim and a sulfonamide?

<p>1:20 (A)</p> Signup and view all the answers

Why do commercially available preparations use a ratio of 1:5 for the combination of trimethoprim or ormetoprim and a sulfonamide?

<p>Due to pharmacokinetic considerations (D)</p> Signup and view all the answers

When are sulfonamides most effective?

<p>In the early stages of acute infections (D)</p> Signup and view all the answers

What happens once the stores of folic acid, purines, thymidine, and amino acids are depleted?

<p>Bacteriostasis occurs (A)</p> Signup and view all the answers

Why are adequate cellular and humoral defense mechanisms critical for successful sulfonamide treatment when used as sole agents?

<p>To counteract the bacteriostatic nature of sulfonamides (B)</p> Signup and view all the answers

What is the most common mechanism of resistance to sulfonamides?

<p>Increased affinity of altered proteins (C)</p> Signup and view all the answers

Why are sulfonamides less effective in purulent environments?

<p>Due to increased concentration of PABA (A)</p> Signup and view all the answers

What is a common characteristic among all sulfonamides?

<p>Cross-resistance between different species (B)</p> Signup and view all the answers

Which microorganisms are highly resistant to sulfonamides?

Signup and view all the answers

What is the main reason why a group of diaminopyrimidines is used in combination with sulfonamides?

<p>To block microbial enzyme systems sequentially (B)</p> Signup and view all the answers

Which of the following best describes the effect of using diaminopyrimidines alone against bacteria?

<p>Moderately effective and resistance develops rapidly (A)</p> Signup and view all the answers

What is the role of sulfonamides when used in combination with pyrimethamine to treat protozoal diseases?

<p>Potentiate the effect of pyrimethamine (A)</p> Signup and view all the answers

What is the basis for the use of triple sulfonamide mixtures clinically?

<p>Higher solubility compared to single drug at the same total concentration (C)</p> Signup and view all the answers

Which functional group substitution results in compounds with varying physical, chemical, pharmacological, and antibacterial properties?

<p>Substitution on the amido group (A)</p> Signup and view all the answers

What happens to the solubility of N4-acetylated sulfonamides compared to their nonacetylated forms?

<p>Decreases (B)</p> Signup and view all the answers

What is the pKa range for sulfonamides of therapeutic interest?

<p>$4.8-8.6$ (A)</p> Signup and view all the answers

How are water-soluble sodium or disodium salts of sulfonamides used for parenteral administration prepared?

<p>As highly alkaline solutions (A)</p> Signup and view all the answers

How do diaminopyrimidines such as trimethoprim inhibit bacteria and protozoa?

<p>By competitively inhibiting dihydrofolate reductase (DHFR) (A)</p> Signup and view all the answers

Which enzyme is facilitated by PABA as a substrate for the synthesis of dihydrofolic acid?

<p>Dihydropterate synthetase (DPS) (A)</p> Signup and view all the answers

What does blockade of several enzymes needed for the biogenesis of purine bases result in?

<p>Inhibition of growth and replication (A)</p> Signup and view all the answers

At what concentrations do sulfonamides exhibit a bactericidal action?

<p>High concentrations found in urine (D)</p> Signup and view all the answers

What is the mechanism of action of potentiated sulfonamides?

<p>Inhibition of folic acid synthesis (D)</p> Signup and view all the answers

What is the reason for commercially available preparations to use a ratio of 1:5 for the combination of trimethoprim or ormetoprim and a sulfonamide?

<p>Pharmacokinetic considerations (D)</p> Signup and view all the answers

What is the primary reason for the lag period before the effects of sulfonamide treatment become evident?

<p>Bacteria use existing stores of folic acid and other compounds (A)</p> Signup and view all the answers

What is the most common mechanism of resistance to sulfonamides?

<p>Altered proteins with decreased affinity (D)</p> Signup and view all the answers

Why are sulfonamides less effective in purulent environments?

<p>Release of PABA from decaying neutrophils (C)</p> Signup and view all the answers

What leads to bacteriostasis once the existing stores are depleted?

<p>Depletion of folic acid, folinic acid, purines, thymidine, and amino acids (D)</p> Signup and view all the answers

What characteristic distinguishes potentiated sulfonamides from standard sulfonamides in terms of antibacterial efficacy?

<p>Potentiated sulfonamides are bactericidal while standard sulfonamides are bacteriostatic (D)</p> Signup and view all the answers

What effect does overproduction of PABA have on the inhibition of dihydropterate synthetase?

<p>Precludes inhibition of dihydropterate synthetase (B)</p> Signup and view all the answers

What is the main factor influencing the efficacy of sulfonamides?

<p>Cellular and humoral defense mechanisms (B)</p> Signup and view all the answers

What is the primary factor determining the antibacterial efficacy of potentiated sulfonamides?

<p>Concentration at the site of infection (C)</p> Signup and view all the answers

What renders potentiated sulfonamides time dependent in their antibacterial efficacy?

<p>Bacteriostatic nature (C)</p> Signup and view all the answers

What leads to an optimal ratio for the combination of trimethoprim or ormetoprim and a sulfonamide at the site of infection?

<p>Pharmacokinetic considerations (A)</p> Signup and view all the answers

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