Therapeutic Drug Monitoring : Handling & Reporting

Prepared by :

Siti Fathiyyah binti Mazelan

Pegawai Farmasi UF48

Hospital Tanah Merah

Flow Chart of TDM Sampling

What to Screen ?

• Sampling Tube
• Sampling Time
• Specimen Stability

Ensure the tube is correct!

Plain Tube WITHOUT GEL

Adults: 3-5mL

Bullet Tube

Pediatric: 0.5mL

ALL drugs EXCEPT Cyclosporin

EDTA tube

Adults: 3-5mL

Cyclosporin ONLY

Do NOT SPIN

Sampling Time

Specimen Stability

TDM Verification

TDM Verification

2

Edit sampling details

TDM Verification in PhIS

Print 1 copies

TDM Sample Management in PhIS (1)

TDM Sample Management in PhIS (2)

TDM Sample Management in PhIS (3)

• Key in the required details
• 1 sample 1 sample management

TDM Sample Management in PhIS (3)

• Key in the required details
• 1 sample 1 sample management

TDM Reporting

TDM Reporting in PhIS (1)

TDM Reporting in PhIS (2)

TDM Reporting in PhIS (3)

TDM Reporting in PhIS (4)

TDM Reporting in PhIS (5)

* Once confirm cannot edit

Handle by PRP

Discussed with: PF

Report prepared by: PRP

Report checked by: PF

Handle by PF

Discussed with: PF

Report prepared by: PF

Report checked by: PF

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Compulsory entry:

Who to take charge?

Weekdays

PH/ Weekends

What to Check?

• Patient’s name
• Correct drug
• Weight / PMA &PNA
• Pre & Post levels
• The recommendation:
• Dose
• Frequency
• Starting date
• Starting time
• Re-monitor level on:
• Date
• Time

**Always correlate the intervention with the laboratory results or clinical conditions.

Double check the recommendation

Double check the recommendation

Gentamicin

Case Scenario (1)

Patient currently on IV Gentamicin 12mg OD (3.9 mg/kg/day)

SrCr (21/06/24) : 35 umol/L

Weight : 3.07 Age : 6 Days

PRE : 0.57 mg/L (<1)

POST : 7.35 mg/L (5-12)

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Ke : 0.114 hr-1

T1/2 : 6.098 hr

T : 18.24 hr

Cmax: 7.78 mg/L

Cmin : 0.509 mg/L

Vd :1.64 L (0.538 L/kg)

Patient currently on IV Gentamicin 9mg OD (3.8mg/kg/day)

Last dose : 21/6/2024 @ 3pm

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Weight : 2.35kg Age: 10days

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SrCr (21/06/24) : 51.17 umol/L

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PRE : 2.05 mg/L (<1)

POST : 8.07 mg/L (5-12)

​

Ke : 0.061 hr-1

T1/2 : 11.38 hr

T : 34.136 hr

Cmax: 8.32 mg/L

Cmin : 1.93 mg/L

Vd : 1.408L (0.599 L/kg)

Case Scenario (2)

Case Scenario (2)

If 9mg 36hourly,

Expected Cmax: 7.197mg/L

Expected Cmin : 0.8mg/L

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Suggestion:

1. Monitored PRE is TOXIC and POST level is WITHIN therapeutic range.
2. Suggest to WITHOLD for 36 hours from the last dose and change regime to IV Gentamicin 9mg 36hourly to be served on 23/6/2024 at 6AM.
3. Kindly monitor renal profile closely.
4. Thank You

Case Scenario (3)

Patient currently on IV Gentamicin 13mg OD (3.98 mg/kg/day)

SrCr (20/06/24) : 73 umol/L

PRE : 2.16 mg/L (<1)

POST : 11.18 mg/L (5-12)

​

Ke : 0.073 hr-1

T1/2 : 9.484 hr

T : 28.452 hr

Cmax: 11.596 mg/L

Cmin : 2.008 mg/L

Vd : 1.36 L (0.416 L/kg)

Amikacin

Case Scenario (1)

Patient currently on IV Amikacin 35mg OD (11.86 mg/kg/day)

SrCr (21/06/24) : 37.59 umol/L

Weight : 2.95kg Age : 7 days OL

POST 2H : 26.52 mg/L

POST 7H : 10.72 mg/L

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• Ke : 0.181 hr-1
• T1/2 : 3.825 hr
• T : 11.476 hr
• Cmax: 31.78 mg/L
• Cmin : 0.413 mg/L
• Vd : 1.12 L (0.378 L/kg)

Vancomycin

Vancomycin

Reference

• Clinical Pharmacokinetic Pharmacy Handbook Second Edition (2019)

Vancomycin

Vancomycin in Normal Renal Function

Patient currently on IV Vancomycin 1000 mg BD (12.5 mg/kg/dose)

Last dose served on 13/5/24 at 8.00pm

SCr: 71 umol/L (8/5/24)

​

Pb: right wrist abscess

Tissue c&s (10/5/24) : MRSA positive

12/5/2024 : iv vancomycin 1500mg STAT

​

PRE : 8.32 mg/L (10-20)

POST :17.69 mg/L (20-40)

​

​

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Vancomycin in Normal Renal Function

Vancomycin in Normal Renal Function

Ke :0.079 hr-1

T1/2 : 8.728 hr

T : 26.18 hr

Cmax: 19.152 mg/L

Cmin : 7.386 mg/L

Vd : 84.96 L ( 1.062 L/kg)

​

AUC inf: 13.269

AUC elim: 148.93

AUC 24: 324.398

​

By using Vd population:

• Exp AUC24: 344.64mg.hr/L

Vancomycin in Normal Renal Function

Vancomycin in Normal Renal Function

• Calculated AUC24: 324.4 mg.hr/L was BELOW therapeutic range (400-600).
• Suggest to INCREASE IV Vancomycin 1250 mg BD ( 15.6 mg/kg/dose) starting today (14/5/24 @ 8pm) .
• Kindly dilute IV Vancomycin 1250mg in 250ml NS and run over 2hours.
• To take pre and post level on 15/5/24 @ 7.30pm and 11pm, respectively.
• Kindly monitor renal profile closely.
• Thank you.

Paracetamol

Guide for PCM Toxicity

1. Do confirm

• Dose
• Weight of patient
• Strength of paracetamol
• Type of paracetamol (ER/IR)
• Type of Ingestion (Acute/Chronic Ingestion)
• Any symptoms (Nausea/Vomiting/Abdominal pain)
• Time of Ingestion

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2. If Multiple Ingestion

• Do not use Rummack Matthew Nomogram
• May Commence NAC

3. If Acute Ingestion

• Use Rummack Matthew Nomogram

4. NAC dose kindly refer CPPH