Table 1 Comparison of oral dosing requirements for representative highly protein bound drugs

Clindamycin (95 %)

Antimicrobial

Respiratory tract, skin, soft tissue, and peritonitis

MIC susceptibility: medically significant pathogens

Staphylococcus aureus: 0.016 μg/ml—>256 μg/ml

Streptococcus pneumoniae: 0.002 μg/ml—>256 μg/ml

Streptococcus pyogenes: <0.015 μg/ml—>64 μg/ml

Q6 h

Furosemide (91–99 %)

Diuretic

Kidney

Not well defined; varies based on disease state and desired effect

20–80 mg; repeat 6–8 h as needed; titrated up to 600 mg/d

Naproxen (99 %)

Anti-inflammatory

Peripheral tissues at site of inflammation

Trough plasma concentrations of 13–51 µg/mL at 500 mg Q12 h

250–1000 mg/d depending on indication and severity

Tolbutamide (96 %)

Hypoglycemic

Pancreas (beta cells)

ATP-dependent K+ currents of mouse pancreatic B-cells (patch-clamp technique): in the absence of albumin, tolbutamide blocked currents half maximally at 4.1 µmol/L

Initial dose: 1–2 g. Maintenance dose: 0.25–3 g daily

Efavirenz (99.5–99.75 %)

Antiretroviral

Throughout the body—site of infection and the reverse transcriptase enzyme

Plasma concentrations above 2 mg/L appear to suppress HIV replication

600 mg/d

Warfarin* (>98 %)

Anticoagulant

Blood

Effective concentrations influenced by many factors. Titrated based on INR response

Doses range from 0.5 mg daily to >20 mg; average dose 4–5 mg/d

Phenytoin (>90 %)

Anticonvulsant

Brain (motor cortex)

The clinically effective serum trough concentration is usually 40 to 80 µmol/L.

300 mg/d

Valproic Acid (90–95 %; saturable)

Anti-epileptic, Anticonvulsant

Brain

The therapeutic range for valproic acid (total) is 50–125 µg/mL

Doses vary by indication; average dose 500 mg/d; some patients benefit from doses up to 1000 mg/d

Diazepam+ (98.5 %)

Anti-anxiolytic

Brain/GABA_A receptor

Effective plasma concentrations 150–400 ng/mL

2–10 mg 2–4 times a day