Introduction
Shingles is caused by so-called herpes zoster viruses. These are caused by the Varicella Zoster Virus. This virus triggers chickenpox when first infected.
Afterwards the viruses remain in the body. Usually they rest there and do not cause any symptoms. However, they can be reactivated decades after the initial infection.
This can happen due to an immune deficiency, cancer, HIV infection or for no reason. The reactivation of these viruses manifests itself as shingles. The drug treatment of shingles has basically three different goals.
The acute pain should be relieved. In addition, the aim is to limit the spread of the skin changes. In addition, the aim is to prevent complications, such as post-zosteric neuralgia. To achieve these goals, various drugs are available. You can find out how infectious shingles is in our article How infectious is shingles?
What prescription drugs are available?
Prescription drugs for the treatment of shingles are virustatics and glucocorticoids and some stronger painkillers. Since shingles is caused by viruses, antiviral drugs are used. These are not only intended to improve the symptoms locally on the skin, but also to fight the viruses systemically in the body.
Prescription drugs are Aciclovir, Zostex (Brivudin), Famciclovir and Valaciclovir. Orally taken prescription glucocorticoids, such as cortisone, are sometimes also part of a treatment for shingles. They may have anti-inflammatory effects.
However, their use should be kept to a minimum due to the side effects of cortisone. If post-zosteric neuralgia develops, it is possible that its treatment may require prescription medication. In the context of this complication, patients may suffer from neuropathic pain for weeks after rashes have healed.
The pain treatment is usually divided into 4 stages. For advanced, more severe pain (stages 3 and 4), prescription painkillers from the group of opioids are sometimes used. Examples of active substances here are morphine or buprenorphine.
Prescription co-analgesics can also be given in all stages of pain treatment. These are drugs that are actually used for other diseases but have an additional pain-relieving effect. For example, amitriptilin, a tricyclic antidepressant, is used as a co-analgesic.
The antidepressant effect is not important in the case of shingles. Accordingly, the drug is prescribed in a much lower dose than it would be in the case of depression. Amitriptiline inhibits, among other things, the sodium channels.
Since these sodium channels are increasingly built into the brain during the development of neuropathic pain, inhibition of the channels has an analgesic effect. Aciclovir is a so-called nucleoside analogue. Nucleoside analogues mimic a component of DNA.
If this nucleoside analogue is inserted instead of a “real” component of the DNA, the DNA construction is interrupted. Aciclovir is specific for the viral DNA construction, therefore the active ingredient does not normally destroy human cells, but only the construction of the viral DNA. As a result, fewer side effects can occur.
As a rule, Aciclovir is well tolerated. The dose is between 200 – 800 mg per tablet. The dosage depends on the severity of shingles.
As a rule, 4 – 5 tablets per day are prescribed. In individual cases side effects may occur. According to the manufacturer, 1 – 10 out of 100 treated persons complain of rashes, itching, headaches, nausea or dizziness.
At present, no interactions with other drugs and the active ingredient Aciclovir are known. Since there are no sufficient studies in pregnancy, one should – as with any medication taken during pregnancy – weigh up the benefit-harm ratio with the treating gynaecologist. During the breastfeeding period, the active substance seems to be relatively harmless.
Taking it should always be discussed together with the doctor. In patients with limited kidney function, the dosage must be adjusted. The active ingredient Valaciclovir is a further development of the active ingredient Aciclovir.
It is a so-called prodrug. This means that the active substance is only activated in the body. Since Valaciclovir is only activated in the body, it has a better so-called bioavailability.This means that the active ingredient is more widely distributed in the body and can have a stronger effect.
However, due to the increased effect, side effects may theoretically occur more frequently. But since the active ingredient is better absorbed, the side effects should be less frequent overall. More than 1 in 10 patients experience nausea and headaches when treated with Valaciclovir.
Occasionally confusion, vomiting and abdominal pain may occur. Valaciclovir is contraindicated in children, pregnant women, persons over 65 years of age, persons with cardiovascular diseases and persons with kidney or lung dysfunction. If other medications are taken that put pressure on the kidneys or liver, the dose may need to be adjusted.
Usually the medication is taken for 7 days. The dosage depends on the severity of shingles. Usually it is 1000 mg 3 times a day. The commercial drugs containing Valaciclovir are for example Valtrex®, Viropel®, Valdacir® and Valaciclomed®.
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