Cendox
Cendox (Doxycycline Hyclate 100 mg, Centurion Lab) — tetracycline antibiotic for cholera adjunct, traveller’s diarrhoea, second-line H. pylori eradication, Q fever and brucellosis. WHO Essential Medicine. Worldwide shipping from MedsBase.
✓ Medically reviewed by Morgan Ellis — Pharmacy Researcher · 8 years experience · Last reviewed: May 2026
⚡ Quick Answer — What is Cendox?
Cendox is doxycycline hyclate 100 mg capsule — a tetracycline antibiotic active against a wide range of Gram-positive, Gram-negative, atypical, intracellular, and zoonotic organisms. In a gastro-health context, doxycycline is used for cholera adjunct therapy, traveller’s diarrhoea (especially when invasive E. coli or Vibrio is suspected), Helicobacter pylori second-line eradication, Whipple’s disease, and Q fever. Standard adult dose: 100 mg twice daily for 1–14 days depending on indication. Manufactured by Centurion Lab under WHO-GMP standards.
Why order from MedsBase
📦 Every order is covered by our Reshipment Assurance Policy — if your parcel does not arrive within 20 business days, we reship it.
Why order from MedsBase
Cendox is supplied from a WHO-GMP certified manufacturer. Every order ships discreetly worldwide and is covered by our Reshipment Assurance Policy — if it does not arrive within 20 business days, we reship at no cost. Doxycycline is on the WHO Essential Medicines List for several indications including cholera, brucellosis, leptospirosis, and Q fever — antibiotics with this safety and spectrum profile are increasingly precious as bacterial resistance widens.
Mechanism
Doxycycline binds reversibly to the 30S bacterial ribosomal subunit, blocking aminoacyl-tRNA from attaching to the A-site and halting protein synthesis. It is bacteriostatic at usual doses. Unlike older tetracyclines, it has high oral bioavailability (~95 percent) that is only modestly reduced by food, a long half-life (~18 hours) allowing twice-daily dosing, and biliary plus intestinal excretion that minimises renal-dose adjustment.
Gastrointestinal indications
- Cholera (Vibrio cholerae): adjunct to oral rehydration, single 300 mg dose or 100 mg twice daily for 3 days
- Traveller’s diarrhoea (suspected ETEC or Vibrio): 100 mg twice daily for 3 days
- H. pylori second-line eradication (after metronidazole/clarithromycin failure): doxycycline 100 mg BD + bismuth + PPI + metronidazole for 14 days
- Whipple’s disease maintenance: 100 mg twice daily long-term (after IV ceftriaxone induction; specialist)
- Q fever (Coxiella burnetii): 100 mg twice daily for 14–21 days (chronic Q fever needs 18 months + hydroxychloroquine)
- Brucellosis: 100 mg twice daily + rifampicin 600–900 mg daily for 6 weeks
Other common uses (cross-category)
- Acne vulgaris (low-dose 50–100 mg/day for 3 months)
- Chlamydia, urethritis, PID (100 mg twice daily for 7–14 days)
- Lyme disease (100 mg twice daily for 14–21 days)
- Malaria prophylaxis (100 mg daily, started 1–2 days before travel)
- Atypical pneumonia (100 mg twice daily for 7–14 days)
- Rosacea, periorificial dermatitis, hidradenitis (sub-antimicrobial 40 mg/day MR)
Dose
Adults: 100 mg twice daily on day 1 (or 200 mg single first dose), then 100 mg twice daily — or 100 mg once daily for less serious infections. Maximum 200 mg/day. Children > 8 years: 4 mg/kg/day in 1–2 divided doses, max 200 mg/day. Hepatic impairment: dose reduce. CrCl: no reduction needed. Take with a full glass of water and remain upright 30 minutes; can be taken with food (modest reduction in absorption).
Side effects
- GI: nausea, vomiting, diarrhoea, oesophagitis (mostly preventable with upright posture and water)
- Skin: photosensitivity (very common), rash; rare Stevens-Johnson syndrome and DRESS
- Dental: permanent staining if used in children < 8 or pregnancy after 18 weeks
- Hepatotoxicity (rare; LFTs in long courses)
- Benign intracranial hypertension (rare)
- Vaginal candidiasis, oral thrush
- C. difficile-associated diarrhoea (rare)
Drug interactions
- Antacids, iron, zinc, calcium, dairy products, sucralfate, bismuth, PEG laxatives: chelate doxycycline and reduce absorption — separate by 2 hours before or 6 hours after.
- Warfarin: doxycycline displaces warfarin from albumin and can raise INR — check INR a few days into the course.
- Combined OC pill: a small theoretical effect through bowel-flora alteration; for short courses (< 14 days) extra contraception is no longer routinely advised by most modern guidelines.
- Carbamazepine, phenytoin, barbiturates: induce doxycycline metabolism — reduce levels.
- Methotrexate: doxycycline may raise methotrexate levels.
Frequently Asked Questions
Why is it in a gastro category?
Doxycycline is the standard adjunct to oral rehydration in cholera, has a role in suspected invasive traveller’s diarrhoea, and is part of bismuth quadruple therapy for second-line H. pylori eradication. The gut category lists it because of these GI uses.
Can I take it with milk or yoghurt?
Avoid taking it with milk, yoghurt, or calcium-fortified drinks — dairy chelates doxycycline and reduces absorption by 30–50 percent. Separate by 2 hours.
Why must I stay upright after the dose?
Doxycycline can cause severe oesophagitis (chemical burn of the oesophagus) if a tablet lodges there. Take with at least 250 mL water and remain upright (sitting or standing) for 30 minutes.
How careful should I be with sun?
Very. Doxycycline is one of the most photosensitising oral drugs in common use. Sunburn can develop within an hour of moderate sun exposure. Use SPF 50+ daily and reapply, wear long sleeves and a hat, and avoid solariums.
Will it stain my teeth?
Only if you are pregnant after 18 weeks or under 8 years old. After permanent teeth have erupted (around age 8) the staining risk is gone.
Is it safe in pregnancy?
No after 18 weeks gestation. Avoid in early pregnancy too unless the indication is severe (e.g. life-threatening Q fever, anthrax) and no alternative exists.
Can I drink alcohol?
Light alcohol is acceptable. Heavy alcohol increases hepatotoxicity risk and reduces immune response to infection.
What if I miss a dose?
Take it as soon as you remember unless close to the next dose. Do not double up. Maintaining the dose interval matters more than catching up.
Will it interact with my contraceptive?
For courses under 14 days, modern guidelines no longer routinely recommend extra contraception. Use condoms if you are concerned or if breakthrough bleeding occurs.
Storage
Below 25°C in a dry place. Avoid freezing. Keep capsules in the original blister.
Cendox doxycycline is an effective single agent for chlamydia, Q fever, and Lyme; if you’re using it specifically as doxy-PEP within a broader HIV-prevention regimen, our PrEP Starter Pack (Tenvir-EM + doxycycline 100 mg) bundles Tenvir-EM with the doxycycline in matched supply tiers.
Other Gastro Health Medications
- Ciplox — Ciprofloxacin (alternative for invasive enteric infection)
- Synclar — Clarithromycin (H. pylori first-line)
- Rcifax — Rifaximin (gut-selective)
- Rifagut — Rifaximin
- Divaine — Minocycline (related tetracycline)
- Browse all Gastro Health Medications
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Ranked by recent MedsBase order volume — what other customers in this category are picking.
| Strength | 100 mg |
|---|---|
| Quantity | 30 Capsule/s, 60 Capsule/s, 90 Capsule/s |
| Pharma Form | Capsule/s |
| Manufacturer | Centurion Lab |
| Treatment | Gastro Health |
| Generic Brand | Doxycycline Hyclate |
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