Rapidly absorbed after PO administration. Protein binding: 13%–18%. Rapidly converted by hydrolysis to the active compound acyclovir. Widely distributed to tissues and body fluids (including CSF). Primarily eliminated in urine. Removed by hemodialysis. Half-life: 2.5–3.3 hr (increased in impaired renal function).
|Creatinine Clearance||Herpes Zoster||Genital Herpes|
|50 ml/min or higher||1 g q8h||500 mg q12h|
|30–49 ml/min||1 g q12h||500 mg q12h|
|10–29 ml/min||1 g q24h||500 mg q24h|
|Less than 10 ml/min||500 mg q24h||500 mg q24h|
Well absorbed and rapidly converted to ganciclovir by intestinal and hepatic enzymes. Widely distributed. Slowly metabolized intracellularly. Primarily excreted unchanged in urine. Removed by hemodialysis. Half-life: 18 hr (increased in impaired renal function).
|Creatinine Clearance||Induction Dosage||Maintenance Dosage|
|60 ml/min or more||900 mg twice a day||900 mg once a day|
|40–59 ml/min||450 mg twice a day||450 mg once a day|
|25–36 ml/min||450 mg once a day||450 mg every 2 days|
|10–24 ml/min||450 mg every 2 days||450 mg twice a wk|
Treatment of simple, complex (petit mal) absence, mixed seizures; divalproex for manic episodes in bipolar disorder, complex partial seizures, migraine prophylaxis; unapproved: tonic-clonic (grand mal) seizures
Well absorbed from the GI tract. Protein binding: 80%–90%. Metabolized in the liver. Primarily excreted in urine. Not removed by hemodialysis. Half-life: 6–16 hr (may be increased in hepatic impairment, the elderly, and children younger than 18 mo).
Poorly absorbed after PO administration. Food decreases peak plasma concentration. Protein binding: 95%. Metabolized in the liver. Recovered primarily in feces and, to a lesser extent, in urine. Unknown if removed by hemodialysis. Half-life: 6 hr.
PO: Poorly absorbed from the GI tract. Primarily eliminated in feces. Parenteral: Widely distributed. Protein binding: 55%. Primarily excreted unchanged in urine. Not removed by hemodialysis. Half-life: 4–11 hr (increased in impaired renal function).
Staphylococcal Enterocolitis, Antibiotic-Associated Pseudomembranous Colitis Caused by Clostridium difficile
• Administer IV slowly over 1 hr; administration that is too rapid can lead to a fall in B/P (monitor) and a red rash on the face, neck, and chest caused by local histamine release. No specific treatment is required for this reaction; evaluate recovery progress.
An erectile dysfunction agent that inhibits phosphodiesterase type 5, the enzyme responsible for degrading cyclic guanosine monophosphate in the corpus cavernosum of the penis, resulting in smooth muscle relaxation and increased blood flow.
Rapidly absorbed after PO administration. Extensive tissue distribution. Protein binding: 95%. Metabolized in the liver. Excreted primarily in feces; a lesser amount eliminated in urine. Drug has no effect on penile blood flow without sexual stimulation. Half-life: 4–5 hr.