Pharmacokinetics Ampicillin Ceftriaxone Vancomycin Half-Life: 1-1.8 hr Protein Bound: 15-25% Absorption: oral 50% Metabolism: hepatic Excretion: urine 5-9 hr Protein Bound: 85% to 95% Absorption: IM: well absorbed Metabolism: liver Excretion: urine (33%-65%); feces Half-life: 5-11 hr Distribution widely in body tissues and fluid Protein Bound: 10-50% Excretion (IV): urine (oral): feces

Pharmacokinetics Rifampin Meropenem Absorption: oral well absorbed Distribution: highly lipophilic; crosses blood-brain barrier well Protein Bound: 80% Half-life 3-4 hr Metabolism: hepatic; undergoes enterohepatic recirculation Excretion: feces (60-65%) and urine (~30%) as unchanged drug Vd: adults: ~0.3 L/kg Distribution: penetrates well into most body fluids & tissues; Protein Bound: 2% Metabolism: hepatic Excretion: urine (~25% as inactive metabolites) Half-Life 1-1.5 hr

Pharmacotherapy of meningitis Because herpes encephalitis can resemble bacterial meningitis at presentation acyclovir is usually included with the initial empirical therapy, IV 10-15 mg/kg/dose every 8 hours for 10-14-21 days Pharmacokinetics Absorption: oral: 15-30% Protein Bound: 9-33% Half-life: 3 hr Peak Plasma Time Oral: within 1.5-2 hr IV: within 1 hr Metabolism: hepatic (small amounts) Excretion: urine (30-90% as unchanged drug)

Pharmacokinetics of dexametasone Half-Life: 2-3.5 hr Onset: IM: 8-24 hr Peak Plasma Time: IM: within 8 hr PO: 1-2 hr Vd: 2 L/kg Metabolism: liver Excretion: mainly in urine, minimally in bile

Levodopa The main pharmacokinetics parametres Peak Plasma Time: 0.5 hr (conventional), 2 hr (XR); Peak Plasma Concentration: XR is 35% conventional. Duration 5 hr (short duration improvement), 3-5 days (long duration response). Vd: levodopa 65% body weight Protein Bound: 10-30% Metabolism: hepatic metabolism Excretion: Urine (80-85%)

Dopamine agonists Apomorphine. Initial: 2 mg (0.2 mL) SC The main pharmacokinetics parametres Peak Plasma Time:10-60 min. Half-life, elimination: 30-60 min. Vd: 218 L. Metabolism: hepatic metabolism. Excretion: Urine (93%); feces (16%).

Dopamine agonists Pramipexole The main pharmacokinetics parametres Peak Plasma Time: 2 hr (IR); 6 hr (ER), Bioavailability: >90%. Protein Bound: 15%/ Vd: 500 L. Metabolism <10%. Half-Life: 8 hr (12 hr in elderly)/ Excretion: urine 90%.

Dopamine agonists Ropinirole The main pharmacokinetics parametres Peak Plasma Time: (Conventional) 1-2 hr; (ER) 6-10 hr. Bioavailability: 55%. Protein Bound: 40%. Half Life: (ER): 6 hr. Vd: 525L. Metabolism: Hepatic CYP1A2. Excretion: Urine.

Dopamine agonists Rotigotine The main pharmacokinetics parametres Bioavailability: 37%. Peak plasma time: 15-18 hr. Protein Bound: 92% (in vitro); 89.5% (in vivo). Vd: 84 L/kg. Metabolism: hepatic. Half-life, biphasic: 3 hr (initial); 5-7 hr (terminal). Excretion: 71% urine; 23% feces.

Antiviral drug Amantadine The usual dosage is 100 mg given twice a day when used alone. The main pharmacokinetics parametres Onset: Within 48 hr (antidyskinetic). Peak plasma time: 2-4 hr. Half-life elimination: 16 hr (avg; normal renal function). Vd: 3-8 L/kg. Protein Bound: 67%. Bioavailability: 86-90%. Metabolism: hepatic Excretion: Urine (80-90% unchanged)

Anticholinergics Trihexyphenidyl Initial: 1 mg PO first day, then increase by 2 mg q3-5days until reach 6-10 mg/days. Maintenance: 5-15 mg/day PO divided q6-8hr. The main pharmacokinetics parametres Half-Life elimination: 33 hr. Onset: 1 hr. Peak effects: 1.3 hr. Duration: 6-12 hr. Metabolism: Unknown. Excretion: Urine and bile.

Anticholinergics Benztropine mesylate 1-2 mg/day (range 0.5-6 mg) PO/IV/IM qHS OR divided q6-12hr. Initiate at low doses (0.5-1 mg) qHS and titrate by 0.5 mg q5-6Days. The main pharmacokinetics parameters Onset of action: 1hr (PO); 15 min (parenteral). Duration: 6-48 hr. Protein Bound: 95%. Bioavailability: 29%.

Anticholinergics Benztropine mesylate 1-2 mg/day (range 0.5-6 mg) PO/IV/IM qHS OR divided q6-12hr. Initiate at low doses (0.5-1 mg) qHS and titrate by 0.5 mg q5-6Days. The main pharmacokinetics parameters Onset of action: 1hr (PO); 15 min (parenteral). Duration: 6-48 hr. Protein Bound: 95%. Bioavailability: 29%.

MAO-B inhibitors Selegiline Conventional 5 mg PO at breakfast & 5 mg at lunch (10 mg/day). Not to exceed 10 mg/day. Orally-disintegrating (with levodopa/carbidopa). Initial 1.25 mg PO qDay, may increase after 6 weeks if inadequate response, no more than 2.5 mg/day. The main pharmacokinetics parameters Peak plasma time: (conventional) 0.5-0.9 hr; (ODT) 15-40 min. Half-life elimination: 10 hr (PO); 18-25hr (TD). Duration: 24-72hr (PO). Bioavailability: 10%. Protein Bound: 90%. Vd: 300 L. Metabolism: cytochrome P-450 enzymes. Excretion: Urine.

MAO-B inhibitors Rasagiline at a dosage of 1 mg once daily is given as monotherapy. The main pharmacokinetics parameters Half-Life elimination: 1.3-3 hr. Peak Plasma Time: 1 hr. Bioavailability: 36%. Protein Bound: 88-94%. Vd: 87 L. Metabolism: liver, primarily CYP1A2 (in vitro data). Excretion: Urine (62%); feces (7%).

COMT Inhibitors Tolcapone The usual dosage is 100-200 mg PO q8hr. Always as an adjunct to levodopa/carbidopa The main pharmacokinetics parameters Peak Plasma Time: 2 hr. Bioavailability: 65-85%. Protein Bound: >99.9%. Half-life elimination: 2-3hr. Vd: 9 L. Metabolism: Liver glucuronidation. Excretion: Urine (60%); feces (40%).

COMT Inhibitors Entacapone The usual dosage is 200 mg PO with each dose of levodopa/carbidopa Not to exceed 1600 mg/day. The main pharmacokinetics parameters Peak Plasma Time: 1 hr. Bioavailability: 35%. Protein Bound: 98%. Vd: 20 L. Half-life elimination: 0.4-0.7 hr (B-phase); 2.4 hr (Y-phase). Metabolism: Hepatic glucuronidation. Excretion: Feces (90); urine (10%).

Para-aminophenol derivative Nonopioid Analgesics Para-aminophenol derivative Acetaminophen 650–1000 mg q 6–8 h Pharmacokinetics Peak Plasma Time: 10-60 min 8 hr (PO 650 mg, extended-release tablet) Peak Plasma Concentration: 1.8 -2.1 mcg/mL Distribution: 1 L/kg Protein Bound: 10 to 25% Metabolism: Liver (microsomal enzyme systems); conjugation (glucuronic/sulfuric acid) Half-life elimination: 1.25-3 hr Excretion: urine Time to Peak: Oral: 10-60 minutes IV: 15 minutes

NSAID The main pharmacokinetics parameters of indoles Indomethacin Bioavailability: 100% Onset: 30 min Duration: 4-6 hr Protein Bound: 99% Vd: 0.34-1.57 L/kg Metabolism: Liver Half-life: 1 hr (initial phase); 2.6-11.2 hr (2 phase) Excretion: urine 60% feces >33% Diclofenac Bioavailability: 50-60% Protein Bound: 99-99.8% Vd: 1.3-1.4 L/kg Metabolism: liver (hydroxylation and conjugation with glucuronic acid, taurine amide, sulfuric acid) Half-life: 1.2-2 hr Excretion: urine 50-70% feces 30-35%

NSAID The main pharmacokinetics parameters Nabumetone Onset: Several days Protein Bound: >99% Vd: 29-82L Metabolism: Hepatic Half-life elimination: 24 hr Excretion: urine (80%) feces (9%) Piroxicam Half-life:14-158 hr (average 50 hr) Onset: 15-30 min -1 hr Duration: 48-72 hr Protein Bound: 99.3% Vd: 0.12-0.14 L/kg Metabolism: hydroxylation; conjugation by cyclodehydration Excretion: urine, feces

NSAID The main pharmacokinetics parameters Ibuprofen Ketoprofen Naproxen Half-life 2-4 hr Onset 30-60 min <30 1 hr Duration 4-6 hr 6 hr 4-7 hr Vd 0.12 L/kg 0.1 L/kg 0.16 L/kg Protein Bound 90-99% 99% <99% Bio availability 80-100% 90% 95% Metabolism Rapid hepatic oxidation hepatic hepatic conjugation Excretion Urine 50-60% (<10% unchanged) Urine 50-90% feces 1-8% Urine 95%; feces <5% e

NSAID The main pharmacokinetics parameters Aspirin Meclofenamate Half-life 2-3 hr (low dose); 15-30 hr (higher dose) 40 min-5.3 hr Onset PO 5-30 min; PR 1-2 hr 30 min Duration PO 3-6 hr PR >7 hr Vd 0.15-0.2 L/kg Protein Bound 90-95% 99.8% Bio availability 80-100% 26% Metabolism Hepatic via microsomal enzyme system Hepatic Excretion principally in urine (80-100%), saliva, feces urine (70%); feces (20-30%) e

Opioid Analgesics The main pharmacokinetics parameters Phenyl butazone Ketorolac Celecoxib Half-life 60 hr 2-6 hr 11 hr Onset IM: 10 min; PO: 30-60 min Duration 6-8 hr Vd 0.11-0.33 L/kg 7.14 L/kg Protein Bound 98% >99% 97% Bio availability 80-100% undetermined Metabolism hepatic hepatic (CYP2C9) Excretion urine Urine (91%); feces feces 57%; urine 27%

Opioid Analgesics The main pharmacokinetics parameters Codeine Hydrocodone Propoxyphene Half-life: 3-5 hr Onset: Rapid Duration: 2-4 hr (SC/IM) Peak Plasma Time: SC 40-60 min; IM 30-50 min Bioavailability: 50-60%; Protein Bound: 60-80% Metabolism: liver Excretion: urine (primarily) Half-life: 3.3-4.4 hr Duration: 4-8 hr Peak Plasma Time: 1.3 hr (single 10 mg dose) Concentration: 23.6 ng/ml (single 10 mg dose) Excretion: urine (mainly) Half-life: 6-12 hr Duration: 4-6 hr Peak Plasma Time: 2-2.5 hr Concentration: 50-120 ng/mL Metabolism: prolonged, hepatic

Opioid Analgesics The main pharmacokinetics parameters Fentanyl Levorphanol Half-life 2-4 hr 12-16 hr Onset immediate (IV) 7-15 min (IM) 10-60 min (PO) Duration 1-2hr (IM); 0.5-1hr (IV) 4-8 hr Vd Protein Bound 80-85% Bio availability 50% Metabolism hepatic Excretion urine (75%), feces urine

Opioid Analgesics The main pharmacokinetics parameters Meperidine Methadone Morphine Half-life 0.5-1 hr 8-59 hr 1.5-4.5 hr Onset 30-60 min (PO); 10-30 min (IM) 0.5-1 hr (oral); 10-20 min (parenteral) 15-30 min (PO); <5 min (IV) Duration 4-6 hr up to 7 hr Vd 3.5 L/kg (PO); 2.6 L/kg (IM) 1-4.7 L/kg (IV) Protein Bound 25% 85-90% 36% (IV) Bio availability 36-100% Metabolism liver Excretion urine, feces urine urine & feces