Drug reference

Doxycycline

Tetracycline · Antibiotic

Also known as Doxycycline hyclate, Doxycycline monohydrate

START

100 mg PO BID × D1 then 100 mg once daily

TYPICAL MAX

200 mg/day

STOP IF

Pregnancy · children <8y · esophagitis history

WATCH

Photosensitivity · pill esophagitis · candidal overgrowth

CDSCO approvedSchedule HJan AushadhiATC J01AA02

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 1h · GI absorption
PEAK: 2h · Cmax
t½: 18h · plasma t½
DURATION: 1d · once-daily dosing window

EXCRETION

Biliary + fecal · minimal renal/CYP

route + CYP

INTERACTIONS

12 major

incl. contraindicated

PREGNANCY

Category D — fetal tooth/bone deposition

FDA category + note

Top interactionssee all 12 →

IsotretinoinContraindicatedDatabaseDDInter
CarbamazepineSevereTextbook-citedKDT 7e · p949
DesogestrelSevereTextbook-citedKDT 7e · p949
EthinylestradiolSevereTextbook-citedKDT 7e · p949

Available in India

215 branded formulations and 191 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Jan Aushadhi — generic available at GoI pharmacies

Mechanism

Doxycycline is a bacteriostatic antibiotic that inhibits bacterial protein synthesis by reversibly binding to the 30S ribosomal subunit. This action prevents the attachment of aminoacyl-tRNA to the mRNA-ribosome complex, thereby inhibiting peptide chain elongation. Its broad-spectrum activity targets various gram-positive and gram-negative bacteria, as well as atypical organisms like Rickettsia, Chlamydia, and Mycoplasma.

Indications

Bacterial infections (e.g., respiratory tract, urinary tract, skin and soft tissue, rickettsial infections, chlamydia, mycoplasma)Acne vulgaris (moderate to severe)RosaceaMalaria prophylaxis and treatmentLyme diseaseAnthrax (prophylaxis and treatment)CholeraBrucellosisFilariasis (as an adjunct to eliminate Wolbachia endosymbionts)Syphilis (alternative treatment)Legionnaires' diseasePeriodontitis (adjunct to scaling and root planing) (off-label)Small intestinal bacterial overgrowth (SIBO)short-term chemoprophylaxis in areas with chloroquine- and mefloquine-resistant malariacombined with quinine/quinidine for p. falciparum and p. vivax from chloroquine-resistant areasfilarial infection (Wuchereria bancrofti, Onchocerca volvulus)reducing severe eyelid inflammationblepharitis (due to anti–matrix metalloproteinase activity)Malaria (prophylaxis for travellers to endemic areas)Plague (prophylaxis for contacts during an epidemic)Prevention of acute exacerbations in chronic obstructive lung disease (doubtful value)Prevention of acute exacerbations in chronic bronchitis (doubtful value)Leptospirosis (curative, second choice to penicillin)Leptospirosis prophylaxis (in subjects at risk during an epidemic)nonpenicillinase producing gonorrhoea (alternative)early syphilis (alternative)late syphilis (alternative)chlamydia trachomatislymphogranuloma venereumgranuloma inguinale/donovanosischancroid (alternative)prophylaxis (alternative regimen for CQ-resistant P. falciparum for short-term visitors)uncomplicated vivax malaria (in occasional chloroquine resistance, with quinine)uncomplicated CQ-resistant falciparum malaria (as an alternative regimen with quinine)Treatment of CQ-resistant falciparum as well as vivax malaria (only in combination with quinine)Treatment of mefloquine/chloroquine/S/P-resistant falciparum malaria (in combination with artesunate)Prophylaxis for short-term travellers to CQ-resistant P. falciparum areascommunity-acquired methicillin-resistant S. aureus (CA-MRSA) strainsNongonococcal Urethritis (NGU)Chlamydia trachomatis infectionEpididymitis (caused by N. gonorrhoeae or C. trachomatis)Pelvic Inflammatory Disease (PID)Lymphogranuloma Venereum (LGV) proctitisProctitis (empirical treatment)HIV-1 acquisition prevention (Doxycycline PEP in MSM and transgender women)Oral therapy for skin and soft tissue infections sensitive to methicillinOral therapy for skin and soft tissue infections resistant to methicillinAdjunctive antibiotic for patients with moderate or severe dehydration due to cholera (in areas with confirmed susceptibility)Moderate or severe Vibrio parahaemolyticus–associated gastrointestinal illnessVibrio vulnificus primary sepsis (combined with a third-generation cephalosporin)Brucellosis (acute nonfocal)Brucella endocarditisAntimicrobial prophylaxis for Brucella exposure (monotherapy or combined with rifampin for 3 weeks)Primary syphilis (for penicillin-allergic patients, nonpregnant, CSF normal or not examined)Secondary syphilis (for penicillin-allergic patients, nonpregnant, CSF normal or not examined)Early latent syphilis (for penicillin-allergic patients, nonpregnant, CSF normal or not examined)Late latent syphilis (for penicillin-allergic patients, nonpregnant, HIV-uninfected, CSF normal)Post-exposure prophylaxis (PEP) within 72h of exposure for prevention of syphilis in MSMNeurosyphilis (possible alternative, limited data)Mild leptospirosisModerate/severe leptospirosisChemoprophylaxis of leptospirosisLymphatic filariasis (targeting Wolbachia, with macrofilaricidal activity and improvement in filarial lymphedema)Onchocerciasis (macrofilaristatic, rendering female adult worms sterile)Mansonella perstans infection

Dosing

Adult: Most susceptible infections: 100 mg orally every 12 hours on day 1, then 100 mg orally once daily. Severe infections (e.g., anthrax): 100 mg orally every 12 hours. Acne/Rosacea (anti-inflammatory dose): 20 mg orally twice daily or 40 mg once daily (modified-release formulation).…
Pediatric: For children >8 years and >45 kg: adult dose. For children >8 years and <45 kg: 2.2 mg/kg orally every 12 hours on day 1, then 2.2 mg/kg orally once daily (max 100 mg/dose).
Renal adjustment: No dose adjustment generally required in renal impairment as it is primarily eliminated via feces.
Hepatic adjustment: Use with caution in patients with severe hepatic impairment; monitor liver function. Consider lower doses if severe.
Geriatric: No specific dose adjustment needed. Use with caution due to potential for multiple comorbidities and polypharmacy; monitor for adverse effects.
Max dose: Generally 200 mg/day for most indications, though up to 400 mg/day for severe life-threatening infections (e.g., anthrax, cholera).

Pharmacokinetics

Onset

Rapid absorption

Peak effect

1.5-4 hours

Duration

18-24 hours

Half-life

12-22 hours

Bioavailability

90-100% after oral administration

Protein binding

80-95%

Metabolism

Partially metabolized in the liver to inactive metabolites; significant enterohepatic recirculation.

Excretion

Primarily via feces (biliary excretion and direct gut secretion of unchanged drug); a smaller proportion is excreted via urine.

Contraindications

Hypersensitivity to doxycycline or other tetracyclines
Children under 8 years of age (due to risk of permanent tooth discoloration and bone growth inhibition)
Pregnancy (especially during the second and third trimesters)
Severe hepatic impairment (use with caution)
Patients with impaired esophageal transit (risk of esophageal ulceration)
Concurrent use with isotretinoin (increased risk of pseudotumor cerebri)
Young children (not routinely recommended)
children less than 8 years of age
pregnant women
known hypersensitivity to tetracyclines
Below 6 years (deposits in developing teeth and bone, discolors and weakens them)
Pregnancy (acute yellow atrophy of liver, pancreatitis and kidney damage in mother; teeth and bone deformities in offspring)
Young children
pregnant women (for prophylaxis)
children < 8 years (for prophylaxis)
Children

Side effects

Common

NauseaVomitingDiarrheaAbdominal discomfortPhotosensitivity (sunburn-like reaction)Esophageal irritation/ulceration (especially if taken without adequate fluid or lying down)Candidiasis (oral/vaginal)HeadacheGI disturbancesAbdominal paindizzinessphotosensitivityesophagitisodynophagiaLocal irritancySuperinfection risk (especially diarrhoea)Pseudomembranous enterocolitisJarisch-Herxheimer-like reaction (approx 15% of patients during the first 24h of therapy)

Serious

Pseudotumor cerebri (idiopathic intracranial hypertension)
Severe cutaneous adverse reactions (e.g., SJS, TEN, DRESS)
Clostridioides difficile-associated diarrhea (CDAD)
Hepatotoxicity
Blood dyscrasias (rare)
Anaphylaxis
hepatotoxicity (rarely)
pancreatitis (rarely)
benign intracranial hypertension (rarely)
Liver and kidney damage
Antianabolic effect
Fetal bone-growth abnormalities (avoid in pregnancy and children <8 years old)

Pregnancy & lactation

Pregnancy

Category D — fetal tooth/bone deposition

Lactation

Doxycycline is excreted into breast milk. Although the amount is generally small and infant systemic absorption is limited due to chelation with calcium in milk, it is generally recommended to avoid during prolonged use or high doses due to theoretical risk of dental staining or inhibition of bone growth. Short-term use (e.g., 7-10 days) may be considered with careful infant monitoring.