Anti-Viral & Antiparasitic Medications — Acyclovir for Herpes and Vermox (Mebendazole) for Parasitic Worm Infections
Reviewed by Dr. Sarah Mitchell, RPh, Clinical Pharmacist — Updated January 2026
This category contains three medications that address two clinically distinct types of infection. Aciclovir Cream 5% and Acyclovir Tablets (Zoviclovir 200mg) are antiviral agents targeting the Herpes Simplex Virus (HSV) — one topically for cold sores, one orally for herpes outbreaks. Vermox Generic (Mebendazole 100mg) is an antiparasitic anthelminthic agent used to treat intestinal worm infections such as pinworms, roundworms, whipworms, and hookworms — it is not an antiviral. Understanding what each medication does and does not treat is essential for using these products correctly.
Products in This Category — What Each Treats
| Product | Active ingredient | Drug class | Treats | Does NOT treat |
|---|---|---|---|---|
| Aciclovir Cream 5% | Acyclovir 5% w/w | Antiviral (topical) | Cold sores (HSV-1) on lips and face; genital herpes lesions (HSV-2) topically | Does not prevent outbreaks. Does not reduce transmission. Not for internal use. Not for eyes. |
| Acyclovir Tablets (Zoviclovir 200mg) | Acyclovir 200mg | Antiviral (oral) | Genital herpes outbreaks (HSV-2); oral herpes (HSV-1); herpes zoster (shingles); varicella (chickenpox) | Does not cure herpes. Does not prevent viral transmission. Not for bacterial infections or colds. |
| Vermox Generic (Mebendazole 100mg) | Mebendazole 100mg | Antiparasitic (anthelminthic) | Pinworms, roundworms, whipworms, hookworms, threadworms — intestinal parasitic worm infections | Does NOT treat viral infections, bacterial infections, colds, or flu. Not for tapeworms outside the intestine. |
Important classification note from Dr. Sarah Mitchell, RPh: Vermox (mebendazole) is not an antiviral medication — it is an anthelminthic (antiparasitic) agent. It has no activity against viruses, bacteria, or fungi. It treats only intestinal parasitic worm infections. It appears in this category for administrative purposes but belongs pharmacologically to the antiparasitic drug class.
How Acyclovir Works — The Viral DNA Polymerase Mechanism
Acyclovir's mechanism is one of the most elegant in pharmacology — it exploits a unique enzyme found only in herpes-infected cells, making it highly selective and minimally toxic to healthy tissue:
Aciclovir Cream vs Acyclovir Tablets — Which to Use and When
Both products contain the same active molecule but are used for different clinical situations. Choosing the right form matters for efficacy:
From Dr. Sarah Mitchell, RPh: The most common clinical mistake with acyclovir is delayed initiation. Both the cream and oral tablets are significantly more effective when started during the prodromal phase — the tingling, itching, or burning sensation that precedes visible lesions — or at the very onset of a lesion. Waiting until lesions are fully developed substantially reduces the benefit of treatment. Have your medication ready before an outbreak occurs.
Vermox Generic (Mebendazole 100mg) — Antiparasitic Treatment for Intestinal Worm Infections
Classification clarification: Mebendazole (Vermox) is an anthelminthic (antiparasitic) agent — not an antiviral. It has no activity against viruses. It treats intestinal parasitic worm infections by a mechanism entirely unrelated to antiviral drugs. It is listed in this category for website organization purposes only.
Mebendazole works by binding to β-tubulin in intestinal parasite cells, blocking the formation of microtubules — the structural protein scaffolding the worm needs for cell division, glucose absorption, and survival. This mechanism is highly selective: human tubulin binds mebendazole far less efficiently than parasite tubulin, explaining the drug's safety profile at standard therapeutic doses. The worms are immobilized and die gradually over 1–3 days, then are expelled naturally in faeces.
Vermox Dosage — By Parasite Type (Health Canada / Vermox Product Monograph)
| Parasite | Dose | Schedule | Notes |
|---|---|---|---|
| Pinworm (Enterobiasis) | 100mg (1 tablet) | Single dose, repeat at 2 weeks and 4 weeks | 3 doses needed because first dose kills worms but not eggs. Treat all household members simultaneously. |
| Roundworm, Whipworm, Hookworm | 100mg twice daily | Morning and evening for 3 consecutive days | No special diet or fasting required. Tablets may be chewed, swallowed whole, or crushed into food. |
| Mixed infestation | 100mg twice daily | 3 days | If symptoms persist after 3 weeks, physician may prescribe second treatment course. |
Important for pinworm infections: All household members — including those without symptoms — should be treated simultaneously. Pinworms spread easily through contaminated surfaces, bedding, and hand-to-mouth contact. Without treating the whole household, reinfection typically occurs within weeks. Thorough handwashing, especially before meals and after using the toilet, is essential throughout treatment.
Frequently Asked Questions
Does acyclovir cure herpes? No. Acyclovir suppresses active HSV replication but cannot reach the latent virus reservoir — where HSV hides in sensory nerve ganglia between outbreaks. No currently available antiviral can cure herpes. Acyclovir reduces outbreak severity, duration, and frequency (with suppressive therapy), but the virus remains in the body permanently.
Is the acyclovir cream as effective as the tablets? For cold sores (herpes labialis), the cream is effective when applied at the very first sign of an outbreak. However, for genital herpes and frequent recurrences, oral acyclovir tablets — or preferably valacyclovir for its superior bioavailability (54% vs 15–20%) — are clinically more effective because they achieve systemic drug levels that topical cream cannot.
Does Vermox work against viruses or bacteria? No. Mebendazole (Vermox) is an antiparasitic medication that kills intestinal worms by disrupting their cellular tubulin. It has no antibacterial or antiviral activity whatsoever. It should not be used for colds, flu, herpes, or bacterial infections.
Do I need a prescription for these products in Canada? Acyclovir (both cream and tablets) is a prescription medication in Canada. Vermox (mebendazole) 100mg for pinworms is generally available without prescription in Canada at most pharmacies. For confirmation of current availability and status, confirm with your pharmacist.
Can I use acyclovir if I am pregnant? Topical acyclovir cream has minimal systemic absorption and is generally considered low-risk in pregnancy based on decades of use. Oral acyclovir is used in pregnancy when the benefit clearly outweighs risk — it is commonly prescribed for severe primary genital herpes in pregnant women. Always inform your doctor or pharmacist if you are pregnant before using any antiviral medication.
How long does delivery take to my province? Standard delivery to all Canadian provinces and territories takes 4–9 business days. All orders ship in neutral packaging with no external reference to the pharmacy name or medication type.
The content on this page is for educational purposes only and does not constitute medical or pharmacological advice. Acyclovir is a prescription medication in Canada. Consult a licensed Canadian healthcare provider before starting antiviral therapy for herpes, particularly for genital herpes, suppressive therapy, or use during pregnancy. Herpes simplex virus infections involve significant transmission risk — a healthcare provider can counsel you on barrier methods and safe sexual practices alongside pharmacological treatment.
