acyclovir vs doxycycline hyclate
Side-by-side comparison of acyclovir and doxycycline hyclate Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Zovirax
Doryx MPC
Acyclovir is an antiviral medicine. It is used to treat infections caused by certain viruses.
Doxycycline hyclate is an antibiotic that fights bacteria in your body. It can treat many different types of infections.
Acyclovir is used to treat shingles, which is caused by herpes zoster. It also treats genital herpes, both the first time you have it and when it comes back. Acyclovir can also treat chickenpox.
This medicine can treat infections like Rocky Mountain spotted fever and typhus. It also treats respiratory infections, some STIs, and infections like plague and cholera. Your doctor will test to make sure doxycycline is the right medicine for your infection.
Acyclovir stops the virus from growing and spreading. It does this by interfering with the virus's ability to make copies of itself. This helps your body fight off the infection.
Doxycycline stops bacteria from growing by interfering with how they make proteins. This helps your body fight off the infection. It is a tetracycline antibiotic.
- • Malaise (feeling unwell)
- • Nausea
- • Diarrhea
- • Nausea
- • Vomiting
- • Diarrhea
- Tiredness 7,612
- Diarrhea 7,064
- Using the medicine for something it's not approved for 5,797
- Lung infection 5,474
- Feeling sick to your stomach 5,330
- The medicine is not working 4,953
- Feeling sick to your stomach 4,734
- Using the medicine for something it's not approved for 4,410
- Feeling very tired 4,376
- Skin irritation 3,920
Acyclovir can cause nervous system problems, especially in older adults or people with kidney problems. Tell your doctor if you have kidney problems before taking this medicine.
Doxycycline can cause permanent tooth discoloration if used during tooth development. Tell your doctor if you have kidney problems.
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if acyclovir will harm an unborn baby. Talk to your doctor about the risks and benefits of taking acyclovir while breastfeeding.
Doxycycline can harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if doxycycline passes into breast milk, so talk to your doctor if you are breastfeeding.
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How to Read This acyclovir vs doxycycline hyclate Comparison
acyclovir is classified in the Antiviral (Nucleoside Analog) drug class, while doxycycline hyclate sits within the Tetracycline Antibiotic (Antimalarial) class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, acyclovir has 31,277 submissions while doxycycline hyclate has 22,393. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between acyclovir and doxycycline hyclate — always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.