Table 1:

Medications used in the treatment of herpes zoster and postherpetic neuralgia

Drug	Dose and duration	Adverse events^*	Daily cost, $^†
Acute herpes zoster^‡
Acyclovir	800 mg five times daily for 7 d1	Common: nausea, vomiting, diarrhea Severe: acute kidney injury, cytopenia, Stevens–Johnson syndrome	6.34
Valacyclovir	1000 mg three times daily for 7 d1	Common: headache, diarrhea, nausea Severe: acute kidney injury, thrombotic thrombocytopenia purpura, cytopenia, hepatitis	5.09
Famciclovir	500 mg three times daily for 7 d1	Common: headache, nausea, confusion Severe: Stevens–Johnson syndrome, hepatitis, thrombocytopenia	5.07
Postherpetic neuralgia
Amitriptyline	12.5–200 mg/d7	Common: anticholinergic effects (dry mouth, urinary retention, confusion) Severe: cardiac arrhythmia, cytopenia	0.12–0.96
Nortriptyline	30–120 mg/d⁷^§	Common: anticholinergic effects (dry mouth, urinary retention, confusion) Severe: cardiac arrhythmia, cytopenia	0.15–0.60
Gabapentin	1800–3600 mg/d⁷^¶	Common: somnolence, fatigue, ataxia Severe: leukopenia, Stevens–Johnson syndrome	1.55–3.09
Pregabalin	300 mg/d⁷^**	Common: dizziness, somnolence, peripheral edema Severe: acute kidney injury, congestive heart failure	2.23
Divalproate	1000 mg/d7	Common: nausea, vomiting, gastrointestinal upset Severe: drug-induced lupus, cytopenia, pancreatitis, hepatitis	2.18
Capsaicin	0.075% cream⁷^††	Common: local burning, coughing	Market price

↵* The adverse events listed are not comprehensive but are a representative sample based on selections from monographs at www.e-therapeutics.ca
↵† Average daily cost in Canadian dollars (excluding dispensing fees) based on data from the Ontario Drug Formulary at www.health.gov.on.ca/english/providers/program/drugs/odbf_mn.html
↵‡ Antivirals (acyclovir, valacyclovir or famciclovir) should be started within 72 h of onset of rash.
↵§ Titrated to maximum tolerable dose.
↵¶ Titrated over a 4-week dose escalation period.
↵** Titrated over a 1-week dose escalation period.
↵†† Typically administered four times daily or by a 60-minute high-concentration patch.