Meds and you

27 September 2013

Valaciclovir

Valaciclovir is an antiviral drug. Antiviral drugs are used to prevent or cure a disease caused by a virus by inhibiting viral growth.

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Valaciclovir is the active ingredient of Zelitrex (Nappi Code: 852228-007 & 817783-008).

General information
Valaciclovir is an antiviral drug. Antiviral drugs are used to prevent or cure a disease caused by a virus by inhibiting viral growth, or by interfering with the ability of the virus to multiply.

In South Africa valaciclovir is registered for the treatment of infections caused by the herpes virus, such as shingles, genital herpes, chickenpox and fever blisters.

Valaciclovir is not a cure for viral infections, but simply slows the virus down while allowing your immune system time to catch up. Treatment with this drug should start as soon as symptoms appear and before the appearance of any lesions.

Treatment with valaciclovir should only be stopped once the prescribed course has been completed, or if your doctor instructs you to do so.

How does valaciclovir work?
Valaciclovir prevents the relevant herpes virus form multiplying by inhibiting enzymes needed for viral DNA replication in cells.

Fast facts

Drug schedule: schedule 4
Available as: valaciclovir is available as tablets.
What does it do? Valaciclovir is an anti-viral drug.
Overdose risk: low
Dependence risk: low
Is Valaciclovir available as a generic? no
Is Valaciclovir available on prescription only? yes

User information

Onset of effect: within 24 hours
Duration of action: up to 12 hours
Dietary advice: valaciclovir can be taken with or without food. It is advised to take each dose with at least 250 ml of water and to drink at least 2 litres of water per day while being treated with this medication.
Stopping this medicine: valaciclovir should only be stopped once the prescribed course has been completed.
Prolonged use: valaciclovir is rarely used for prolonged periods of time. Drug resistance is possible with prolonged use.

Special precautions
Consult your doctor before using this drug if:

 

  • you are allergic to valaciclovir
  • you have a liver or kidney disease
  • if you have reduced immunity
  • if you are taking any other medication

Pregnancy: avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.
Breastfeeding: avoid. It is unknown how this medication may affect your baby. Consult your doctor before use.
Porphyria: this medication is safe to use.
Infants and children: note that a dosage adjustment may be needed.
The elderly: note that a dosage adjustment may be needed.
Driving and hazardous work: caution is advised as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how this medication affects you.
Alcohol: avoid concomitant use of alcohol with this medication.

Possible side effects

 

Side Effect
Frequency
Consult your doctor
 
Common
Rare
Only if severe
In all cases
headache
X
 
X
 
rash
 
X
 
X
abdominal pain
 
X
X
 
diarrhoea
 
X
X
 
drowsiness
 
X
X
 
confusion
 
X
 
X
hallucinations
 
X
 
X
nausea and vomiting
 
X
X
 
tremors
 
X
 
X

Interactions

 

probenecid increased risk of valaciclovir toxicity
cimetidine increased risk of valaciclovir toxicity
pethidine increased risk of valaciclovir toxicity
anticonvulsant drugs possible increased frequency of seizures
theophylline increased risk of theophylline toxicity
zidovudine possibility of extreme lethargy
aminoglycoside antibiotics increased risk of kidney damage

Disease interactions
Contact your doctor before taking acyclovir if you have kidney disease.

Overdose action
A small overdose is no cause for concern. In case of intentional large overdose seek emergency medical attention.

Recommended dosage
Adults: 0.5 - 3 g daily in divided doses depending on infection

 

This material is not intended to substitute medical advice, but is for informational purposes only. Please consult a physician for specific treatment and recommendations.
 
 

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