Treatment

Currently, there are four prescription agents approved in the United States for treatment: acyclovir, famciclovir, penciclovir, and valacyclovir.  There is one agent, docosanol, available without a prescription.18,19

The mechanism of action of acyclovir, famciclovir, valacyclovir and penciclovir is inhibition of viral DNA synthesis. Short-term therapy is usually well tolerated. Treatment should begin within 72 hours of symptom development for maximal clinical  benefit. Treatment has been shown to decrease the duration of fever by two days (one vs. three days), lesions by six days (four vs. ten days), odynophagia by three days (four vs. seven days), and viral shedding by four days (one vs. five days).18  Table 2 shows the adult dosage, and Table 3 summarizes pediatric dosage.

Table 2- Adult Dosage15

Medication

Primary Infection

Recurrence

Acyclovir

400 mg TID or 200 mg five times daily for seven to ten days

 

400 mg TID for five days

Famciclovir

250 mg TID or 500 mg BID for seven to ten days

 

750 mg BID for one day or one dose of 1500 mg

Valacyclovir

1000 mg BID for seven to ten days

 

2g BID for one day

Penciclovir

Apply at the first sign of symptoms every two hours while awake for four days

Apply at the first sign of symptoms every two hours while awake for four days

 

Recurrence: Some patients may only feel prodromal symptoms, slight rash, and disappearance of symptoms without treatment.  Single dosing of valacyclovir or famciclovir offers more convenience at a lower overall cost.

Table 3- Pediatric Dosage20

Medication

Primary Infection

Recurrence

Acyclovir

75 mg/kg/day divided into five doses (max 1g/day) for seven days

 

400 mg five times a day for five days

Valacyclovir (≥12 y.o.)

1000 mg BID for seven days or 2g BID for one day

2g BID for one day

Penciclovir

(≥12 y.o.)

Apply at the first sign of symptoms every two hours while awake for four days

Apply at the first sign of symptoms every two hours while awake for four days

 

Table 4 summarizes additional drug information, including contraindications, adverse effects, and patient information.21-26

Table 4- Drug Information

Drug

Contraindications/Cautions

Common adverse effects

Patient education

Valtrex (Valacyclovir)

Allergy or hypersensitivity to acyclovir, valacyclovir, or any part of the formulation

 

●      Nausea

●      Headache

●      Hepatotoxicity

●      Vomiting

●      Abdominal Pain

●      Can be taken with or without food

●      Drink extra water while taking this medication

●      Do not stop taking if your symptoms resolve before finishing the prescription

Famvir (Famciclovir)

Allergy or hypersensitivity to famciclovir, penciclovir, or any part of the formulation

 

●      Headache

●      Nausea

●      Fatigue

●      Vomiting

●      Diarrhea

●      Pruritus

●      Rash

●      Administer without regard to food

●      Do not stop taking if your symptoms resolve before finishing the prescription

●      The product contains lactose and may cause issues in intolerant individuals.

 

Acyclovir

Hypersensitivity to acyclovir, valacyclovir, or any part of the formulation

●      Malaise,

●      Headache

●      Nausea

●      Vomiting,

●      Diarrhea

●      Neurotoxicity (in renal failure)

●      Acute Kidney Injury

●      Administer without regard to food

●      Drink extra water while taking this medication

Penciclovir

Hypersensitivity to penciclovir or any part of the formulation

●      Skin irritation

●      Headache

●      Allergic reaction at the application site

●      Only apply to Herpes Simplex Labialis on the lips and face

●      Clean and dry the intended area before use

●      Apply an amount necessary to cover the lesions or area of symptoms

●      Wash hands with soap and water after application and avoid application near the eyes.

 

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