Acyclovir acts by blocking the synthesis of the DNA of the viruses by preventing the cell replication without interfering with the replication of human DNA.


What is Acyclovir?


Treatment with acyclovir is indicated in cases of:


  • Treatment of infections from Herpes simplex (HSV) type 1 (non-genital) and type 2 (genital), including the HSV encephalitis;
  • For the suppression of recurrent herpes simplex infections in immunocompetent patients;
  • For the prophylaxis of herpes simplex infections in immunocompromised patients;
  • For the treatment of chickenpox and Herpes zoster (causative agent of chickenpox, which causes reactivation of the so-called "shingles")


How should Acyclovir be taken?


Relative to the pathology to be treated, Acyclovir may be administered through oral intake (tablets or oral suspension), by intravenous or by topical use (ointment to be applied to the labial herpes, for example).


Side effects associated with Acyclovir


Among the “common” side effects associated with Acyclovir there are various gastrointestinal disorders such as:


  • Nausea
  • Vomiting
  • Diarrhea
  • Abdominal pains


Moreover, potential systemic disorders may include:


  • Fatigue
  • Fever
  • Muscle aches


Diseases of the skin and subcutaneous tissue such as:


  • Itching and rashes
  • Psychiatric disorders
  • Nervous system disorders such as headaches and dizziness


Among the "uncommon" side effects associated with Acyclovir are included certain skin disorders such as hives as well as rapid and diffuse hair loss.

On the other hand, the rare side effects associated with the use of Acyclovir may include:


  • Anaphylaxis
  • Disturbance to the immune system
  • Dyspnea (respiratory, thoracic and mediastinal)
  • Angioedema;
  • Reversible increases in bilirubin and liver related enzymes within the hepatobiliary disorders


The "very rare" side effects include hepatobiliary disorders such as:


  • Hepatitis
  • Jaundice


Furthermore, the use of Acyclovir may be associated with renal and urinary disorders such as:


  • Acute kidney failure
  • Kidney pain


Side effects related to disorders of the lymphatic system may include:


  • Anemia
  • Leukopenia
  • Thrombocytopenia


Finally, side effects associated with psychiatric disorders and diseases of the nervous system may include:


  • Agitation
  • Confusion
  • Tremor
  • Ataxia
  • Dysarthria
  • Hallucinations
  • Psychotic symptoms
  • Convulsions
  • Drowsiness
  • Encephalopathy
  • Coma


Contraindications and warnings associated with the use of Acyclovir


Acyclovir can cause pain in the kidneys, especially when the drug is administered rapidly or at high doses, or when the patient is poorly hydrated or already suffering from impaired renal function prior to administration of acyclovir. Therefore, it is good practice to check the parameters of kidney functionality and avoid administering intravenous acyclovir with rapid infusions.

Although acyclovir has highlighted not embryo fetotoxic, its administration in pregnancy requires a careful assessment of risks and benefits for the mother as well as the unborn child.

Lastly, the administration of acyclovir during breastfeeding requires caution: part of the acyclovir is excreted in breast milk, where it reaches a concentration of 0.6 to 4.1 times the corresponding maternal plasma levels.