Introduction

Name

• Doxycycline.
• Doxycycline hyclate.
• Doxycycline monohydrate.
• Doxycycline calcium.

Class of drug

• Lipid-soluble tetracycline antibiotic.

Description

Chemical name

• (4S,4aR,5S,5aR,6R,12aR)-4-(dimethylamino)-1,5,10,11,12a-pentahydroxy-6-methyl-3,12-dioxo-4a,5,5a,6-tetrahydro-4H-tetracene-2-carboxamide.

Molecular formula

• C₂₂H₂₄N₂O₈.

Molecular weight

• 444.44.

Physical properties

• Available in hyclate, calcium and monohydrate salts.
• Hyclate:
  • Used in the injectable dosage form and in oral tablets and capsules.
  • Also known as doxycycline HCl.
  • Yellow, crystalline powder.
  • Soluble in water and slightly soluble in alcohol.
• Monohydrate:
  • Used in the oral powder for reconstitution.
  • Yellow, crystalline powder.
  • Very slightly soluble in water and sparingly soluble in alcohol.
• Calcium salt: found in the oral syrup.

Storage requirements

• Tablets and capsules should be stored in tight, light resistant containers, at room temperature.
• The hyclate injection, when reconstituted to up to 1 mg/mL may be stored refrigerated for 72 h.
• Frozen reconstituted solutions (10 mg/mL in sterile water) are stable for at least 2 months if kept at -20°C/-4°F.
• If stored at room temperature, solutions up to 1 mg/mL are stable for 12-48 h.

Uses

Indications

• Drug of choice in rickettsia Arthritis: rickettsia, Borrelia Arthritis: borrelial, leptospirosis Leptospirosis
• Drug of choice in avian chlamydiosis.
• Recommended when tetracyclines are indicated in animals with renal impairment.
• Preferred by some to oxytetracycline for use in birds.

Administration

Precautions

Interactions

with other drugs

Antacids, aluminum, calcium, magnesium and iron salts

• Absorption of doxycycline reduced Aluminum antacid Magnesium sulfate.

Phenobarbitone, phenytoin and primidone

• Increase the metabolism of doxycycline thus decreasing the plasma levels Phenobarbital Phenytoin Primidone.

Sucralfate

• Absorption of doxycycline reduced.

Proton pump inhibitors

• Absorption of doxycycline reduced.

Adverse Reactions

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.

Other sources of information

• BSAVA Small Animal Formulary. Ramsey I (2017) 9th edn. BSAVA, UK