Aciclovir
In stock
200mg · 400mg · 800mg
from 37,89 £
In brief
Herpes viruses can remain dormant in the body between episodes of symptoms. Aciclovir helps control active infection by interfering with viral DNA production, but it does not remove that dormant reservoir.
Pharmacological mechanism of action
Aciclovir disrupts viral replication through targeted molecular interference. As a nucleoside analogue, its antiviral activity specifically inhibits infected cells while largely sparing healthy ones. Key characteristics include:
- Converts to active form by viral thymidine kinase enzymes
- Terminates DNA chain growth during viral replication
- Minimal metabolism with over 75% excreted unchanged through kidneys
- Limited oral bioavailability (15-30%) necessitates frequent dosing
Notable interactions include reduced elimination when combined with probenecid and increased renal toxicity risk alongside nephrotoxic medications. Moderate alcohol consumption appears compatible, though dehydration from excessive intake may elevate crystalluria risk. This targeted mechanism preserves host cells while disabling viral proliferation.
Approved aciclovir indications
Cold sores (herpes labialis)
Aciclovir cream applied five times daily reduces healing time for herpes simplex virus type 1 lesions. Oral treatment provides systemic management for severe outbreaks.
Genital herpes
Both initial episodes and recurrent herpes simplex virus type 2 infections respond to 400mg tablet regimens. Suppressive therapy minimises outbreak frequency.
Shingles treatment
High-dose 800 mg tablets combat varicella-zoster virus reactivation. Early initiation proves critical for reducing postherpetic neuralgia risks.
Chickenpox management
Paediatric protocols initiate within 24 hours of rash onset. Child-specific suspensions ensure accurate weight-based administration while reducing transmission.
UK guidelines occasionally extend to herpetic whitlow and eczema herpeticum as clinically appropriate. Always follow British National Formulary paediatric antiviral protocols for child treatments.
Off-label applications and special populations
Immunocompromised patients
Higher intravenous doses or extended courses prevent life-threatening herpesvirus dissemination in transplant and HIV populations under specialist supervision.
Pregnancy considerations
There is no documented human foetal harm, and genital herpes suppression often continues through the third trimester in line with Royal College of Obstetricians and Gynaecologists guidelines. Neonatal herpes management requires urgent inpatient care.
Geriatric therapy adjustment
Renal function declines typically necessitate 50% dosage reductions when creatinine clearance falls below 25ml/minute. Neuropsychiatric side effect monitoring becomes increasingly important.
Alternative antivirals comparison
For those managing herpes outbreaks, understanding how aciclovir compares to alternatives helps in treatment decisions. Valaciclovir (branded as Valtrex) is a popular NHS choice since it converts to aciclovir in the body but offers more convenient dosing. Famciclovir (Famvir) requires less frequent dosing than aciclovir.
| Medication | Dosing (herpes zoster) | Key advantage |
|---|---|---|
| Aciclovir | 800mg × 5 daily | Available as tablets, suspension and cream |
| Valaciclovir | 1000mg × 3 daily | Reduced dosing frequency |
| Famciclovir | 500mg × 3 daily | Convenient 3x/day dosing |
For topical lip sores, penciclovir cream (branded as Vectavir) is available from pharmacies and shows marginally faster healing times than aciclovir cream in trials. Most patients manage mild outbreaks with aciclovir cream given its pharmacy accessibility without prescription. Pharmacists often suggest valaciclovir for genital herpes suppression due to its simpler regimen supporting adherence over long-term use.
Guidelines for proper use
Correct administration significantly influences aciclovir effectiveness. Timings matter, particularly with oral courses requiring even distribution across waking hours - consider alarms for regimented 800mg 5x/day dosing. Cream application demands careful technique: clean hands, thin layers administered five times daily, avoiding cosmetic coverage until fully absorbed.
Do:
Take tablets with plenty of water to prevent crystalluria
Store tablets below 25°C away from moisture
Complete prescribed courses even after symptom improvement
Don't:
Store creams in refrigerators
Share creams between infected areas or individuals
Discontinue suppression therapy without consulting prescriber
Always read the patient information leaflet (PIL) for storage details. Bathrooms generally prove unsuitable storage environments due to humidity fluctuations. Unplanned "drug holidays" during long-term suppression increase recurrence risks. Pharmacists highlight that topical products maintain effectiveness when used at earliest tingling sensation before blister formation.
