PHR2021: Lab 5

Learning objectives

  • Prepare and dispense mixtures of insoluble therapeutic agents
  • Do so with correct methods (mortar and pestle)
  • Generate appropriate documentation and labelling
PHR2021: Lab 5

Tips

Before commencing

  • Check prescriptions for doses, legality etc.
  • Complete the batch & prescription record
  • Look up and record the solubilities of the ingredients

During preparation

  • Choose appropriate equipment and container
  • Make up to volume during measurement
  • Storage requirement - What does APF say?
PHR2021: Lab 5

Batch Record

Name: Trimethoprim Mixture (CF) 10 mg/mL APF
Batch Number: SH-A006

Batch number Ingredient Formula QD
123456 Trimethoprim 600 mg 2 tablets
123456 Vehicle for Oral Suspension USP NF 30 mL 30 mL
123456 Vehicle for oral solution USP NF to 60 mL to 60 mL
PHR2021: Lab 5

Dose Required

Jane weighs 15 kg

According to APF23:

  • Treatment dose (for acute UTI): 3–4 mg/kg (max 150mg) 12-hourly

  • Prophylaxis: 2mg/kg at night

  • Why is the given dose a little low?

Could the patient have renal dysfunction? (Most likely)

N.B. Giving a sub-optimal might not be ideal because of multidrug-resistant bacteria.

PHR2021: Lab 5

Prescription Record

  • Date: Today's Date
  • Patient's Name: Jane Hannon
  • Patient's Address: 18 Gordon St, Footscray
  • Copy of prescription: As provided
  • Batch No: .
  • Prescriber: Leanne Tang
  • Prescription No.: KD83011
  • Dispensing Pharmacist: Your Initials
PHR2021: Lab 5

Label

KEEP OUT OF REACH OF CHILDREN

SHAKE WELL BEFORE EACH USE

Trimethoprim Mixture CF 10 mg/mL APF (60 mL)
Give THREE (3) mL by measure twice daily at 12-hour intervals for 5 days

Ms Jane Hannon
Prescription No.
Date
Dr L Tang
Dispenser's Initials
Expiry Date: [90 days] (60 if APF25)

Preservative: 0.1% w/v methylparabens and 0.1% w/v potassium sorbate
PROTECT FROM LIGHT REFRIGERATE, DO NOT FREEZE

Name, Address & Tel. No. of Pharmacy and Proprietor's Name

PHR2021: Lab 5

Corollary

  • Suggested CALs:
CAL 7 CAL 7a CAL J
PHR2021: Lab 5

Corollary II

For labelling practice

  • Bring a fineliner

APF25 says Mixture CF, APF26 says Mixture

Microbiology and Immunology explanation - Trimethoprim is a bactericidal agent that inhibits bacterial dihydrofolate reductase, an enzyme involved in the synthesis of folate. Folate is essential for DNA synthesis and cell division. - Bacteria can develop resistance to trimethoprim through various mechanisms, including: - Mutations in the target enzyme (dihydrofolate reductase) that reduce the drug's binding affinity. - Increased production of the target enzyme, leading to reduced drug efficacy. - Active efflux pumps that expel the drug from bacterial cells. - Bacteria can also acquire resistance genes from other bacteria through horizontal gene transfer, which can lead to the emergence of multidrug-resistant strains. - The use of suboptimal doses can contribute to the development of resistance by allowing bacteria to survive and adapt, leading to the selection of resistant strains. This is particularly concerning in the context of multidrug-resistant bacteria, where treatment options become limited and less effective. - Therefore, it is important to use appropriate doses of antibiotics to minimise the risk of resistance development and ensure effective treatment.