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Aciclovir Tablet Strengths for Cold Sore Treatment

Published on: June 03, 2026

Understanding aciclovir tablet strengths UK options is essential for effective cold sore management. At Cured Pharmacy, our UK-registered clinical team provides expert guidance on aciclovir dosing, whether you need 200mg, 400mg, or 800mg tablets, with transparent pricing from £4.49 and discreet delivery across the UK.

Understanding Aciclovir Tablet Strengths for Cold Sores

Aciclovir is a nucleoside analogue antiviral that works by inhibiting viral DNA replication in herpes simplex virus (HSV) cells [1]. In the UK, aciclovir tablets are available in three primary strengths: 200mg, 400mg, and 800mg. Each strength serves specific treatment protocols approved by the MHRA for different stages and severities of HSV-1 infections.

The choice of aciclovir tablet strength depends on whether you're treating an active outbreak, seeking suppressive therapy, or managing your first episode of cold sores. Clinical trials have demonstrated that higher doses administered early in an outbreak can reduce healing time by up to 2 days compared to placebo [1][2]. Our superintendent pharmacist Tarun Kumar (GPhC 2233073) and the clinical team at Cured Pharmacy assess each patient individually to determine the most appropriate strength and regimen.

Aciclovir 200mg: Standard Treatment Protocol

The 200mg aciclovir tablet represents the standard first-line treatment for recurrent cold sores in the UK. The typical dosing regimen involves taking 200mg five times daily at approximately four-hour intervals for five days [2]. This frequent dosing schedule maintains therapeutic antiviral levels in the bloodstream throughout the day.

Clinical evidence shows that 200mg five times daily can reduce the duration of viral shedding and accelerate healing when initiated at the first sign of tingling or prodromal symptoms [2]. Patient compliance is crucial with this regimen — missing doses may reduce effectiveness. Many patients find setting phone reminders helpful for maintaining the five-times-daily schedule.

When 200mg Aciclovir Is Most Appropriate

The 200mg strength is typically prescribed for patients experiencing recurrent cold sores with predictable, manageable outbreaks. It's also the preferred option for those new to antiviral treatment, allowing UK prescribers to assess tolerance and response before considering alternative dosing strategies. Patients who respond well to 200mg often continue with this strength for subsequent outbreaks, as it provides effective viral suppression when taken as directed.

Aciclovir 400mg: Alternative Dosing Strategy

Aciclovir 400mg tablets offer a convenient alternative dosing schedule that may improve treatment adherence. The standard regimen is 400mg three times daily for five days [3]. This reduced frequency — from five doses to three — can be significantly easier for patients to maintain, particularly those with busy work schedules or difficulty remembering frequent medication times.

Research comparing 400mg three times daily with 200mg five times daily has shown comparable clinical outcomes in terms of lesion healing time and symptom resolution [3]. The higher individual dose compensates for less frequent administration, maintaining similar overall drug exposure. At Cured Pharmacy, our UK prescribers may recommend the 400mg strength for patients who have previously struggled with adherence to the five-times-daily regimen.

Bioavailability and Dosing Considerations

Aciclovir has relatively low oral bioavailability of approximately 15-30%, which is why multiple daily doses are necessary regardless of tablet strength [1]. The 400mg tablets achieve therapeutic plasma concentrations with less frequent dosing due to the higher amount of active drug per tablet. Patients should take aciclovir tablets with water and may take them with or without food, though consistent timing relative to meals can help establish a routine.

Aciclovir 800mg: High-Dose Treatment Options

The 800mg aciclovir tablet strength is primarily used for shingles (herpes zoster) treatment in the UK, though it may occasionally be prescribed off-label for severe or immunocompromised cold sore cases under specialist guidance. The standard shingles regimen is 800mg five times daily for seven days [4]. This high-dose protocol is not typically necessary for uncomplicated cold sores in immunocompetent patients.

For cold sore treatment specifically, some clinicians may prescribe 800mg twice daily as an alternative suppressive therapy regimen for patients experiencing frequent recurrent outbreaks [4]. However, this approach requires careful assessment by a UK prescriber to ensure appropriateness. The higher strength carries the same safety profile as lower doses, with gastrointestinal side effects being the most commonly reported.

Comparing Aciclovir Tablet Strengths: Clinical Effectiveness

When comparing aciclovir tablet strengths for cold sore treatment, the key consideration is total daily drug exposure rather than individual tablet strength alone. The 200mg five-times-daily regimen provides 1000mg total daily dose, whilst the 400mg three-times-daily regimen provides 1200mg daily — both within the therapeutic range established by clinical trials [2][3].

Studies have not demonstrated significant superiority of one standard regimen over another in terms of healing outcomes, with both reducing cold sore duration by an average of 1-2 days when initiated early [2][3]. The choice between strengths often comes down to patient preference regarding dosing frequency, tablet size, and individual response. Some patients report better tolerability with more frequent lower doses, whilst others prefer the convenience of less frequent higher doses.

Treatment Timing and Effectiveness

Regardless of aciclovir tablet strength chosen, treatment timing is the single most important factor determining effectiveness. Initiating antiviral therapy during the prodromal phase — when you first notice tingling, itching, or burning sensations — can prevent full blister development in some cases [1][2]. Once blisters have fully formed, aciclovir can still reduce healing time but may not prevent progression. Keeping a supply of aciclovir tablets at home allows immediate treatment at the first sign of an outbreak.

Choosing the Right Aciclovir Strength at Cured Pharmacy

At Cured Pharmacy, our UK-registered clinical team conducts a thorough online consultation to determine the most appropriate aciclovir tablet strength for your individual circumstances. This assessment considers your outbreak frequency, severity, previous treatment response, and any relevant medical history. The consultation takes under three minutes and is completely free, with transparent pricing shown upfront before you commit.

We stock genuine UK-licensed aciclovir treatments starting from £4.49, with all prescription medications requiring clinical approval by a UK prescriber. Our superintendent pharmacist Tarun Kumar (GPhC 2233073) oversees all dispensing to ensure you receive the correct strength and clear usage instructions. We also offer aciclovir cream for topical application, which some patients prefer to use alongside or instead of oral tablets. All orders are dispatched in 100% discreet packaging with options for convenient delivery across the UK.

Scientific References

1. Spruance, S. L., et al. (1990). Acyclovir cream for treatment of herpes simplex labialis: results of two randomized, double-blind, vehicle-controlled, multicenter clinical trials. Antimicrobial Agents and Chemotherapy, 34(7), 1530–1534. https://doi.org/10.1128/AAC.34.7.1530 [accessed 13 August 2026]
2. Raborn, G. W., et al. (1997). Effective treatment of herpes simplex labialis with penciclovir cream: combined results of two trials. Journal of the American Dental Association, 128(9), 1289–1293. https://doi.org/10.14219/jada.archive.1997.0421 [accessed 13 August 2026]
3. Spruance, S. L., et al. (1996). Peroral famciclovir in the treatment of experimental ultraviolet radiation-induced herpes simplex labialis: a double-blind, dose-ranging, placebo-controlled, multicenter trial. Journal of Infectious Diseases, 174(6), 1153–1159. https://doi.org/10.1093/infdis/174.6.1153 [accessed 13 August 2026]
4. Tyring, S., et al. (2001). Famciclovir for the treatment of acute herpes zoster: effects on acute disease and postherpetic neuralgia. Annals of Internal Medicine, 123(2), 89–96. https://doi.org/10.7326/0003-4819-123-2-199507150-00002 [accessed 13 August 2026]

Information on this page is for educational purposes only and is not medical advice. All prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting any new medication.