Author:
Kai Knudsen
Updated:
23 December, 2025
Here you will find recommended therapeutic serum concentrations for a range of medications used in intensive care. The tables present the medications sorted by both generic names and brand names.
Essential Conversions & Core Formulas
Weight & Length
Weight:
• 1 kg = 2.2 lb
• 1 lb = 0.45 kg
Length:
• 1 inch = 2.54 cm
• 1 cm = 0.39 inch
• Quick reference: 6 ft ≈ 183 cm, 5 ft ≈ 152 cm
Temperature
• °F = (°C × 1.8) + 32
• °C = (°F − 32) ÷ 1.8
• Normal: 37 °C (98.6 °F)
• Hypothermia: < 36 °C
Pressure Conversions
• 1 atm = 760 mmHg = 101 kPa
• 1 mmHg = 1.36 cmH₂O
• 1 cmH₂O = 0.74 mmHg
• 1 kPa = 7.5 mmHg
• 1 bar = 750 mmHg
• PEEP 5 cmH₂O ≈ 3.7 mmHg
Volume & Concentration
Volume:
• 1 L = 1000 mL
• 1 mL = 1 cc
Concentration:
• % solution = (% × 10) mg/mL
• 1% = 10 mg/mL
• 0.5% = 5 mg/mL
• 1000 mcg = 1 mg
• 1 mL/kg crystalloid ≈ 1% change in hemoglobin
Infusion Rate Calculations
mcg/kg/min → mL/hr:
Rate = (Dose × Weight (kg) × 60) ÷ Concentration (mcg/mL)
mg/hr → mL/hr:
Rate = Dose (mg/hr) ÷ Concentration (mg/mL)
Units/hr → mL/hr:
Rate = Units/hr ÷ Concentration (units/mL)
Standard Infusion Strengths (verify local protocols)
Vasopressors:
• Epinephrine 1:1000 = 1 mg/mL
• Epinephrine 1:10,000 = 0.1 mg/mL
• Phenylephrine 100 mg/100 mL = 1000 mcg/mL
• Norepinephrine 4 mg/250 mL = 16 mcg/mL
• Vasopressin 20 units/100 mL = 0.2 units/mL
• Dopamine 400 mg/250 mL = 1600 mcg/mL
• Ephedrine 50 mg/10 mL = 5 mg/mL
Hemodynamic Calculations
Mean Arterial Pressure (MAP):
MAP = (SBP + 2 × DBP) ÷ 3
Systemic Vascular Resistance (SVR):
SVR = ((MAP − CVP) ÷ CO) × 80
Normal: 800–1200 dyn·s/cm⁵
Pulmonary Vascular Resistance (PVR):
PVR = ((MPAP − PCWP) ÷ CO) × 80
Normal: 20–120 dyn·s/cm⁵
Cardiac Index (CI):
CI = CO ÷ BSA (Normal: 2.5–4.0 L/min/m²)
Oxygenation Formulas
Oxygen Content (CaO₂):
CaO₂ = (1.34 × Hgb × SaO₂) + (0.003 × PaO₂)
Oxygen Delivery (DO₂):
DO₂ = CO × CaO₂ × 10
Normal: ~520–720 mL/min/m²
A–a Gradient:
A–a = [(FiO₂ × 713) − (PaCO₂ ÷ 0.8)] − PaO₂
Normal: <10–15 mmHg on room air
P/F Ratio:
PaO₂ / FiO₂
ARDS: <300, Severe: <100
Local Anesthetic Concentrations
Lidocaine:
• 0.5% = 5 mg/mL
• 1% = 10 mg/mL
• 2% = 20 mg/mL
Bupivacaine:
• 0.25% = 2.5 mg/mL
• 0.5% = 5 mg/mL
Ropivacaine:
• 0.2% = 2 mg/mL
• 0.5% = 5 mg/mL
Local Anesthetic Maximum Doses
• Lidocaine: 4.5 mg/kg (max 7 mg/kg with epinephrine)
• Bupivacaine: 2.5 mg/kg (max 3 mg/kg with epinephrine)
• Ropivacaine: 3 mg/kg
Monitor for LAST – lipid emulsion 20% as rescue therapy
Therapeutic Drug Concentrations
| Drugs | Label Name | Specimen | Reference values in Serum |
|---|---|---|---|
| Amitriptyline | Saroten, Tryptizol | S-: | 300-700 nmol/L |
| Amlodipine | Amlodipin, Norvasc | S-: | 0,025 mg/L |
| Atenolol | Atenolol, Tenormin | S-: | 0,54 mg/L |
| Carbamazepine | Tegretol, Hermolepsin | S-: | 20-40 µmol/L |
| Citalopram | Citalopram, Cipralex. | S-: | 20-800 nmol/L |
| Digoxin | Lanacrist | S-: | <1,4 nmol/L |
| Phenytoin | Epanutin | S-: | 40-80 µmol/L |
| Flecainide | Tambocor | S-: | 0,5-2,0 µmol/L |
| Fluoxetin | Fontex | S-: | 100-1940 nmol/L |
| Gentamicin | Gentamicin, Garamycin | S-: | 1.5-4.0 mg/L 8 hours after administration. |
| Clomipramin | Anafranil | S-: | 550-1300 nmol/L (Clomipramin + desmetylklomipramin) |
| Clonazepam | Iktorivil | S-: | 35-60-(120) µmol/L |
| Litium | Lithionit | S-: | 0,5 -0,8 mmol/L, sometimes 0,9-1,2 mmol/L |
| Lamotrigin | Lamictal | P-: | 12-56 µmol/L |
| Levetiracetam | Keppra | P-: | 35-120 µmol/L |
| Meropenemanhydrat | Meronem | S-: | 8-10 µg/mL |
| Mirtazapin | Mirtazapin, Remeron | S-: | 35-520 nmol/L |
| Olanzapin | Olanzapine, Zyprexa | S-: | 15-300 nmol/L |
| Oxazepam | Oxazepam, Oxascand | S-: | 0,7-4,2 µmol/L. |
| Paracetamol | Alvedon, Panodil, Reliv | S-: | Reference value not detectable. In case of intoxication, sampling, interpretation of test results and treatment should be in accordance with the Poison Information Center's guidelines. |
| Paroxetine | Paroxetine, Seroxat | S-: | 20-600 nmol/L |
| Propranolol | Propranolol, Inderal | S-: | 0,075-0,1 mg/L |
| Quetiapine | Seroquel | S-: | 50-700 nmol/L |
| Risperidon | Risperidone, Risperdal | S-: | 50-150 nmol/L |
| Salicylates | Trombyl, Treo, Magnecyl, Bamyl, Aspirine | S-: | 1,1-2,2 mmol/L (Adults) |
| Sertraline | Sertraline, Seroxat | S-: | 10-525 nmol/L |
| Tacrolimus | Prograf | B-: | 5-20 µg/L |
| Theophylline | Theophylline, Theo-Dur | S-: | 55-110 µmol/L |
| Tobramycin | Nebcin | S-: | The lowest value should not exceed 2 mg/L. In a test taken 1 hour after initiation of administration, the concentration should be at least 4 mg/L and not more than 12 mg/L. |
| Topiramat | Topimax | S-: | 15-60 µmol/L. |
| Valproate | Ergenyl | S-: | 350-700 µmol/L |
| Vancomycine | Vancocin | S-: | The lowest value should not exceed 15 mg/L. Samples taken 1 hour after completion of infusion should not exceed 50 mg/L. |
| Venlafaxine | Efexor | S-: | 50-900 nmol/L |
| Zuclopentixol | Cisordinol | S-: | 7-30 nmol/L |
Disclaimer:
The content on AnesthGuide.com is intended for use by medical professionals and is based on practices and guidelines within the Swedish healthcare context.
While all articles are reviewed by experienced professionals, the information provided may not be error-free or universally applicable.
Users are advised to always apply their professional judgment and consult relevant local guidelines.
By using this site, you agree to our Terms of Use.
