Drug Calculations

Premedication for a Tiger

  • Weight of the Tiger: 180 kilos
  • Drugs Involved:
    • Metatomidine
    • Ketamine

Metatomidine

  • Dose Rate: 25 micrograms per kilogram
  • Concentration: 10 milligrams per mil
Calculation Steps
  1. Convert Weight to Dose:
    • Weight of Tiger: 180 kg
    • Required Dose = 180 kg * 25 µg/kg
    • Result: 4500 µg
  2. Convert Micrograms to Milligrams:
    • 1000 µg = 1 mg
    • 4500 µg = 4.5 mg
  3. Determine Volume Needed:
    • Concentration: 10 mg/mL
    • Calculate: 4.5 mg ÷ 10 mg/mL = 0.45 mL
    • Important Note: Always write a zero before the decimal point for doses less than one (0.45 mL vs 45 mL).

Ketamine

  • Dose Rate: 3 milligrams per kilogram
  • Concentration: 100 milligrams per mil
Calculation Steps
  1. Convert Weight to Dose:
    • Required Dose = 180 kg * 3 mg/kg
    • Result: 540 mg
  2. Determine Volume Needed:
    • Concentration: 100 mg/mL
    • Calculate: 540 mg ÷ 100 mg/mL = 5.4 mL
Total Volume in Syringe
  • Total Volume Calculation:
    • Volume of Metatomidine: 0.45 mL
    • Volume of Ketamine: 5.4 mL
    • Total Volume: 0.45 mL + 5.4 mL = 5.85 mL

Key Concepts Involved

  • Unit Conversion: Knowing how to convert between micrograms and milligrams.
  • Multiplication: Weight of the animal times the dose rate.
  • Proportional Reasoning: Determining how many milliliters are needed for administration.
  • Addition: Final volume needed in the syringe.

Importance of Process

  • Step-by-Step Recording:
    • Keep written records of every step during calculations.
    • Verify calculations by asking others to review.

Medication Administration Skills

  • Skills Needed:
    • Reading and interpreting drug requirements.
    • Understanding variability in dose rates on bottles (e.g., 0.2 to 0.5 mg/kg).
    • Reasoning behind choosing higher or lower doses based on patient behavior and history.

Xylazine Calculation Example

  • Weight of Cow: 600 kg
  • Dose Rate: 0.15 mg/kg
  • Concentration: 20 mg/mL
  1. Calculate Required Dose:
    • Required Dose = 600 kg * 0.15 mg/kg = 90 mg
  2. Determine Volume Needed:
    • Volume needed = 90 mg ÷ 20 mg/mL = 4.5 mL

Drug Concentrations

  • Xylazine can also come in concentrations of 100 mg/mL.
  • Aceproazine is used in different concentrations (10 mg/mL and 20 mg/mL).

Acknowledgment of Mistakes

  • Reality of Errors:
    • All professionals make mistakes; it's important to have strategies to avoid and correct them.

Fundamentals of Pharmacology

  • Definition: Study of drugs and their effects on biological systems.
  • Pharmacodynamics: Effects of drugs on the body, including metabolism and elimination.
Factors to Consider with Drugs
  • Duration of effect: How often the drug should be administered.
  • Routes of administration: IV is the fastest, followed by IM and SQ.
  • Diagnosis: Essential for targeted treatment rather than just symptom alleviation.
  • Possible side effects: Pros and cons of a treatment plan must be weighed.

Monitoring and Evaluation

  • Regular monitoring for side effects and therapeutic effectiveness.
Drug Selection Process
  1. History and Examination: Gather patient history and perform a thorough examination.
  2. Diagnostic Testing: Use tests to pinpoint the cause of symptoms.
  3. Treatment Planning: Develop a treatment plan based on diagnosis and available drugs.

Conclusion

  • Mastery of drug calculations and administration processes is crucial for veterinary professionals.
  • Continuous practice and vigilance are necessary to minimize medication errors when treating animals.
  • Understanding pharmacology is essential for effective patient care.