Tetracycline and Doxycycline Hyclate Interaction
Drug interaction information between Tetracycline and Doxycycline Hyclate.
Tetracycline and Doxycycline Hyclate have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Tetracycline and Doxycycline Hyclate. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
These drugs are very similar and work in the same way, so taking them together can lead to too much medicine in your system and more side effects.
What To Do
Check with your doctor or pharmacist before using these two medications at the same time.
FDA Label Information
Drug Interactions Because tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage. Since bacteriostatic drugs may interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracyclines in conjunction with penicillin. Absorption of tetracyclines is impaired by antacids containing aluminum, calcium, or magnesium, and iron-containing preparations.
Tetracycline Also Interacts With
- Theophylline major
- Doxycycline moderate
- Minocycline moderate
- Zinc Sulfate minor
- Atovaquone/Proguanil minor
Doxycycline Hyclate Also Interacts With
- Doxycycline minor
- Carbamazepine minor
- Bismuth Subsalicylate minor
- Phenytoin minor
Frequently Asked Questions
Can I take Tetracycline and Doxycycline Hyclate together?
This is a moderate interaction. Check with your doctor or pharmacist before using these two medications at the same time.
How serious is the interaction between Tetracycline and Doxycycline Hyclate?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Tetracycline and Doxycycline Hyclate interact?
These drugs are very similar and work in the same way, so taking them together can lead to too much medicine in your system and more side effects.
Understanding the Tetracycline and Doxycycline Hyclate Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Tetracycline belongs to the Tetracycline Antibiotic class and Doxycycline Hyclate belongs to the Tetracycline Antibiotic (Antimalarial) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: These drugs are very similar and work in the same way, so taking them together can lead to too much medicine in your system and more side effects. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Tetracycline has 12 total documented interactions on file in this dataset, and Doxycycline Hyclate has 5. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Check with your doctor or pharmacist before using these two medications at the same time. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Tetracycline or Doxycycline Hyclate based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.