Product Information:
Centrex 1000 contains 1000mg of the antiviral drug Valacyclovir as its active ingredient. Valacyclovir is actually a pro-drug which means it is a medication or compound that is metabolized in the body to become an active pharmaceutical drug. Upon intake of Valacyclovir, it is quickly converted into Acyclovir, a drug that has demonstrated antiviral activitiy against herpes viruses and varicella zoster virus. The drug actually stops or slows the growth of these viruses inside the body, thus helping the body fight off the viral infection.
Centrex 1000 is prescribed for the treatment of the viral infections such as cold sores which is caused by herpes labialis virus, genital herpes caused by herpes simplex virus, and herpes zoster or known as shingles. It is also used to treat cold sores in children at least 12 years old, and chicken pox caused by varicella zoster virus, in children aged 2 to 18 years.
This medication, however, does not cure and prevent the spread of these viral infections, but it helps reduce symptoms, reduce the severity and length of the outbreak. It helps hasten the healing of sores, reduces pain and itching, and prevents new sores from forming.
Manufacturer
Centrex 1000 is manufactured by Centurion Laboratories
Dosage
A physician will determine the dosage of Centrex per patient as it will depend on the patient’s type of infection, other health conditions, age, weight and the response to the treatment. A patient must consult a physician to get the precise dosage.
This medication is most effective if taken as soon as the first symptom of the viral infection appears. Use of this drug must be within 48 hours after the first symptom appears. For recurrent viral infections such in the case of genital herpes, this drug works best if taken within 24 hours after symptoms appear. Centrex tablets may be taken with or without food, swallowed whole with plenty of water. Drinking extra fluids is recommended to help prevent kidney problems.
Below are the recommended adult dosages for each viral infection:
Cold sores
- -2 grams (2000mg) every 12 hours for 1 day. Treatment should begin at the earliest appearance of symptom such as tingling, burning, or itching
Genital herpes
- -For an initial infection, 1 gram (1000mg) twice a day for 10 days. Treatment should begin within 48 hours of appearance of symptoms.
- -For recurrent infections, 500mg twice a day for 3 days.
- -For prevention of recurrent infections, 500mg once a day for those with 9 or less recurrences in a year, and 1000mg once a day for patients with normal immune function.
Herpes Zoster
- -1 gram (1000mg) 3 times a day for 7 days. Treatment should begin at the appearance of first symptom, within 48 hours of rash onset.
Below are the recommended doses for children:
Cold sores
- -for children aged 12 years and above, 2 grams (2000mg) every 12 hours for 1 day. Treatment should begin at the onset of cold sore symptom
Chicken pox
- -for children aged 2 to less than 18 years, 20mg per kilogram of child body weight, taken 3 times a day for 5 days. Dose must not exceed 1g (1000mg) 3 times a day. Treatment should begin at the earliest onset of symptom.
The duration of therapy with Valacyclovir (Centrex) must be completed even if symptoms start to improve before the viral infection clears. The prescribed dosage must not be changed without the advice of a physician. Avoid skipping doses as the drug works best with a constant blood level of the drug. If a dose is missed, take it as soon as remembered, but skip it if it’s almost time for the next dose. Never double the dose to make up for the missed dose.
Contraindications
Patients with known allergy to the active ingredient Valacyclovir or any of the tablet excipients, and with known allergy to Acyclovir, must not use this medication.
Side Effects
Each patient will respond differently to this medication. Some may experience side effects, but others may do not. Some of the common side effects Valacyclovir include but not limited to:
- -nausea
- -stomach pain
- -vomiting
- -dizziness
- -headache
- -feeling of tiredness
Contact a physician right away in case any of the following serious side effects occur:
- -mental changes such as confusion, agitation, aggression or hallucination
- -speech problems
- -seizure
- -shaky or unsteady movements
Valacyclovir rarely causes life-threatening effects affecting the red blood cells, kidneys and other body parts. Stop the medication and seek medical help right away in case the following side effects occur:
- -fever
- -pale skin
- -easy bruising or unusual bleeding
- -red or pink urine
- -feeling week or tired
- -bloody diarrhea
- -red spots on the skin not related to the viral infection
- -signs of kidney problem like painful or difficult urination, swelling of feet or ankles, little or no urination
- -irregular heartbeat
- -sudden vision changes
- -loss of consciousness
Incidence of a serious allergic reaction of Centrex is rare. It is characterized by a severe rash, itching and swelling of face, throat, and tongue, severe dizziness, and difficulty in breathing. Stop the medication and seek urgent medical attention if it occurs.
Warnings and Precautions
Valacyclovir can harm kidneys and red blood cells. Before taking Centrex, a physician must be informed of any of the following medical conditions:
- -kidney disease
- -HIV or other conditions that weaken the immune system
- -History of kidney or bone marrow transplant
Harmful effects to the kidneys may be increased if this medication is used with other medicines that harm the kidneys. Centrex can interact with the following medications:
- -Other antivirals
- -Chemotherapy
- -Antibiotics
- -Medications for bowel disorders
- -Medications preventing organ transplant rejection
- -Some pain and arthritis medications
- -Injectable osteoporosis medications
The above list is not complete, inform a physician of all medications being taken to prevent any drug interaction and adverse effects.
Caution is advised when driving, using of machineries and performing activities that require alertness for Centrex can cause dizziness.
Only with the consent of a physician should vaccinations be done while taking this medication. This medication may interact with vaccinations such as varicella virus vaccine and zoster vaccine.
This medication does not prevent the spread of herpes. Avoid physical contact or sexual intercourse or use latex condom to prevent the spread of the virus to other people.
Centrex should only be used by pregnant and breastfeeding women, if a physician determines that the benefits of the drug outweighs the risks.
Centrex and Alcohol
Centrex can cause dizziness therefore limiting alcohol consumption is advisable to prevent increasing the risk of side effects.
