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Active substance(s): DOXYCYCLINE HYCLATE

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Doxycycline 100mg Capsules


One capsule contains 100 mg doxycycline base
(as doxycycline hyclate)
For a full list of excipients, see Section 6.1


Hard gelatin capsules, containing spherical yellow to yellowish microgranules,
intended for oral administration.




Therapeutic indications
Doxycycline 100 mg has been found clinically effective in the treatment of a variety
of infections caused by susceptible strains of Gram-positive and Gram-negative
bacteria and certain other micro-organisms.
Respiratory tract infections: Pneumonia and other lower respiratory tract infections
due to susceptible strains of Streptococcus pneumoniae, Haemophilus influenzae,
Klebsiella pneumoniae and other organisms. Mycoplasma pneumoniae pneumonia.
Treatment of chronic bronchitis, sinusitis.
Urinary tract infections caused by susceptible strains of Klebsiella species,
Enterobacter species, Escherichia coli, Streptococcus faecalis and other organisms.
Sexually transmitted diseases: Infections due to Chlamydia trachomatis including
uncomplicated urethral, endocervical or rectal infections. Non-gonococcal urethritis

caused by Ureaplasma urealyticum (T-mycoplasma). Doxycycline 100 mg is also
indicated in chancroid, granuloma inguinale and lymphogranuloma venereum.
Doxycycline 100 mg is an alternative drug in the treatment of gonorrhoea and
Dermatological infections: Acne vulgaris, when antibiotic therapy is considered
necessary. Since Doxycycline 100 mg is a member of the tetracycline series of
antibiotics, it may be expected to be useful in the treatment of infections which
respond to other tetracyclines, such as:
Ophthalmic infections: Due to susceptible strains of gonococci, staphylococci and
Haemophilus influenzae. Doxycycline Capsules are indicated in the treatment of
Trachoma, although the infectious agent, as judged by immunofluorescence, is not
always eliminated. Inclusion conjunctivitis may be treated with oral Doxycycline 100
mg alone or in combination with topical agents.
Rickettsial infections: Rocky Mountain spotted fever, typhus group, Q fever, Coxiella
endocarditis and tick fevers.
Other infections: Psittacosis, brucellosis (in combination with streptomycin), cholera,
bubonic plague, louse and tick-borne relapsing fever, tularaemia glanders,
melioidosis, chloroquine-resistant falciparum malaria and acute intestinal amoebiasis
(as an adjunct to amoebicides).
Doxycycline 100 mg is an alternative drug in the treatment of leptospirosis, gas
gangrene and tetanus.
Doxycycline 100 mg is indicated for prophylaxis in the following conditions: Scrub
typhus, travellers' diarrhoea (enterotoxigenic Escherichia coli), leptospirosis and
malaria. Prophylaxis of malaria should be used in accordance to current guidelines, as
resistance is an ever changing problem.


Posology and method of administration
The usual dosage of doxycycline for the treatment of acute infections in adults is
200mg on the first day (administered as a single dose or divided into two equal doses
with a twelve-hour interval) followed by a maintenance dose of 100mg/day.
In the management of more severe infections (particularly chronic infections of the
urinary tract), 200 mg daily should be given throughout the treatment period.
Exceeding the recommended dosage may result in an increased incidence of side
effects. Therapy should be continued for at least 24 to 48 hours after symptoms and
fever have subsided.

When used in streptococcal infections, therapy should be continued for 10 days to
prevent the development of rheumatic fever or glomerulonephritis.
Dosage recommendations in specific infections:
Acne vulgaris: 50 mg daily with food or fluid for 6 to 12 weeks.
Sexually transmitted diseases: 100 mg twice daily for 7 days is recommended in the
following infections: uncomplicated gonococcal infections (except anorectal
infections in men); uncomplicated urethral, endocervical or rectal infection caused by
Chlamydia trachomatis; non-gonococcal urethritis caused by Ureaplasma
Acute epididymo-orchitis caused by Chlamydia trachomatis or Neisseria gonorrhoea
100mg twice daily for 10 days.
Primary and secondary syphilis: Non-pregnant penicillin-allergic patients who have
primary or secondary syphilis can be treated with the following regimen: doxycycline
200 mg orally twice daily for two weeks, as an alternative to penicillin therapy.
Louse and tick-borne relapsing fevers: A single dose of 100 or 200 mg according to
Treatment of chloroquine-resistant falciparum malaria: 200 mg daily for at least 7
days. Due to the potential severity of the infection, a rapid-acting schizonticide such
as quinine should always be given in conjunction with Doxycycline 100 mg; quinine
dosage recommendations vary in different areas.

Prophylaxis of malaria: 100 mg daily in adults and children over the age of 12 years.
Prophylaxis can begin 1-2 days before travel to malarial areas. It should be continued
daily during travel in the malarial areas and for 4 weeks after the traveller leaves the
malarial area. For current advice on geographical resistance patterns and appropriate
chemoprophylaxis, current guidelines or the Malaria Reference Laboratory should be
consulted, details of which can be found in the British National Formulary (BNF).
For the prevention of scrub typhus: 200 mg as a single dose.
For the prevention of travellers' diarrhoea in adults: 200 mg on the first day of travel
(administered as a single dose or as 100mg every 12 hours) followed by 100 mg daily
throughout the stay in the area. Data on the use of the drug prophylactically are not
available beyond 21 days.

For the prevention of leptospirosis: 200 mg once each week throughout the stay in the
area and 200mg at the completion of the trip. Data on the use of the drug
prophylactically are not available beyond 21 days.
Use for children:
Not recommended see under “contra-indications”.
Use in the elderly:
Doxycycline 100 mg may be prescribed in the elderly in the usual dosages with no
special precautions. No dosage adjustment is necessary in the presence of renal
Renal impairment: Studies to date have indicated that administration of Doxycycline
100 mg at the usual recommended doses does not lead to accumulation of the
antibiotic in patients with renal impairment see under “special warnings and
precautions for use”.
Method of administration
Capsules are for oral administration only.
Doxycycline 100 mg capsules should be administered with adequate amounts of fluid.
This hould be done in the sitting or standing position and well before retiring at night
to reduce the risk of oesophageal irritation and ulceration. If gastric irritation occurs,
it is recommended that Doxycycline 100 mg be given with food or milk. Studies
indicate that the absorption of Doxycycline 100 mg is not notably influenced by
simultaneous ingestion of food or milk.


Hypersensitivity to the active substance, any of the tetracyclines or to any of the
excipients listed in section 6.1.
This product also contains sucrose. Patients with rare hereditary problems of fructose
intolerance, glucose-galactose malabsorption or sucrase-isornaltase insufficiency
should not take this medicine.
The use of drugs of the tetracycline class during tooth development (pregnancy,
infancy and childhood to the age of 12 years) may cause permanent discolouration of
the teeth (yellow-grey-brown). This adverse reaction is more common during longterm use of the drugs but has been observed following repeated short-term courses.
Enamel hypoplasia has also been reported. Doxycycline is therefore contra-indicated
in these groups of patients.
Pregnancy: Doxycycline 100 mg is contra-indicated in pregnancy. It appears that the
risks associated with the use of tetracyclines during pregnancy are predominantly due

to effects on teeth and skeletal development. (see above about use during tooth
Nursing mothers: Tetracyclines are excreted into milk and are therefore contraindicated in nursing mothers. (see above about use during tooth development).
Paediatric population Contra-indicated in children under the age of 12 years. As with
other tetracyclines, doxycycline forms a stable calcium complex in any bone-forming
tissue. A decrease in the fibula growth rate has been observed in prematures given
oral tetracyclines in doses of 25mg/kg every 6 hours. This reaction was shown to be
reversible when the drug was discontinued. (See above about use during tooth


Special warnings and precautions for use
Use in patients with impaired hepatic function: Doxycycline should be
administered with caution to patients with hepatic impairment or those
receiving potentially hepatotoxic drugs. Abnormal hepatic function has
been reported rarely and has been caused by both the oral and parenteral
administration of tetracyclines, including doxycycline.
Use in patients with renal impairment: Excretion of doxycycline by the
kidney is about 40%/72 hours in individuals with normal renal function.
This percentage excretion may fall to a range as low as 1-5%/72 hours in
individuals with severe renal insufficiency (creatinine clearance below
10ml/min). Studies have shown no significant difference in the serum halflife of doxycycline in individuals with normal and severely impaired renal
Haemodialysis does not alter the serum half-life of doxycycline. The antianabolic action of the tetracyclines may cause an increase in blood urea.
Studies to date indicate that this anti-anabolic effect does not occur with
the use of Doxycycline 100 mg in patients with impaired renal function.
Photosensitivity: Photosensitivity manifested by an exaggerated sunburn
reaction has been observed in some individuals taking tetracyclines,
including doxycycline. Patients likely to be exposed to direct sunlight or
ultraviolet light should be advised that this reaction can occur with
tetracycline drugs and treatment should be discontinued at the first evidence
of skin erythema.
Microbiological overgrowth: The use of antibiotics may occasionally result
in the overgrowth of non-susceptible organisms including Candida. If a
resistant organism appears, the antibiotic should be discontinued and
appropriate therapy instituted.
Pseudomembranous colitis has been reported with nearly all
antibacterial agents, including doxycycline, and has ranged in severity
from mild to life threatening. It is important to consider this diagnosis in

patients who present with diarrhoea subsequent to the administration of
antibacterial agents
Oesophagitis: Instances of oesophagitis and oesophageal ulcerations have
been reported in patients receiving capsule and tablet forms of drugs in the
tetracycline class, including doxycycline. Most of these patients took
medications immediately before going to bed or with inadequate amounts of
Bulging fontanelles: in infants and benign intracranial hypertension in
juveniles and adults have been reported in individuals receiving full
therapeutic dosages. These conditions disappeared rapidly when the drug
was discontinued.
Porphyria: There have been rare reports of porphyria in patients
receiving tetracyclines.
Venereal disease: When treating venereal disease, where co-existent
syphilis is suspected, proper diagnostic procedures including dark-field
examinations should be utilised. In all such cases monthly serological tests
should be made for at least four months.
Beta-haemolytic streptococci infections: Infections due to group A
betahaemolytic streptococci should be treated for at least 10 days.
Myasthenia gravis: Due to a potential for weak neuromuscular blockade,
care should be taken in administering tetracyclines to patients with
myasthenia gravis.
Systemic lupus erythematosus: Tetracyclines can cause exacerbation of
Methoxyflurane: caution is advised in administering tetracyclines with
methoxyflurane. See section 4.5.
Some patients with spirochete infections may experience a JarischHerxheimer reaction shortly after doxycycline treatment is started. Patients
should be reassured that this is a usually self-limiting consequence of
antibiotic treatment of spirochete infections.
Patients with rare hereditary problems of fructose intolerance, glucosegalactose malabsorption or sucrase-isomaltase insufficiency should not
take this medicine.

Interaction with other medicinal products and other forms of interaction
There have been reports of prolonged prothrombin time in patients taking
warfarin and doxycycline.

Tetracyclines depress plasma prothrombin activity and reduced doses of
concomitant anticoagulants may be necessary.
Since bacteriostatic drugs may interfere with the bactericidal action of
penicillin, it is advisable to avoid giving doxycycline in conjunction with
Absorption of doxycycline may be impaired by concurrently administered
antacids containing aluminium, calcium, magnesium or other drugs
containing these cations; oral zinc, iron salts or bismuth preparations.
Dosages should be maximally separated.
Phenobarbital, carbamazepine, primidone and phenytoin may increase the
metabolism of doxycycline (reduced half-life). An increase in the daily
dosage of doxycycline should be considered.
Alcohol may decrease the half-life of doxycycline.
The concurrent use of tetracyclines and methoxyflurane has been reported to
result in fatal renal toxicity. See section 4.4.
Doxycycline may increase the plasma concentration of ciclosporin. Coadministration should only be undertaken with appropriate monitoring.
Drugs that induce hepatic enzymes such as rifampicin may accelerate the
decomposition of doxycycline, thereby decreasing its half-life. Subtherapeutic doxycycline concentrations may result. Monitoring concurrent
use is advised and an increase in doxycycline dose may be required.
Laboratory test interactions
False elevations of urinary catecholamine levels may occur due to
interference with the fluorescence test.

Fertility, Pregnancy and lactation
Studies in animals have not demonstrated a teratogenic effect. In humans, the use of
tetracyclines during a limited number of pregnancies has not revealed any specific
malformation to date.
The administration of tetracyclines during the second and the third trimesters results
in permanent discolouration of the deciduous teeth in the offspring. As a
consequence, doxycycline is contraindicated during the second and third trimesters of
pregnancy (see section 4.3).
Low levels of tetracyclines are secreted into the milk of lactating women.
Doxycycline can be used by breast-feeding mothers for short term use only. Long
term use of doxycycline may result in significant absorption by the suckling infant
and is therefore not recommended because of a theoretical risk of dental
discolouration and decreased bone growth of the suckling child.


Effects on ability to drive and use machines
Doxycycline has no or negligible influence on the ability to drive and use


Undesirable effects
The following adverse reactions have been observed in
patients receiving tetracyclines, including doxycycline.
Common: ≥ 1/100 to < 1/10, Uncommon: ≥ 1/1,000 to < 1/100
Rare: ≥ 1/10,000 to < 1/1,000, Very rare: < 1/10,000, Not known (frequency
cannot be estimated from the available data).
MEDRA System organ class
Infections and infestations:

Blood and lymphatic system

Immune system disorders:

Not known: Candidiasis,
staphylococcal enterocolitis, pseudo
membranous colitis (with Clostridium
difficile overgrowth) and inflammatory
lesions (with candidal overgrowth) in
the anogenital region.

Not known: Thrombocytopenia,
neutropenia, eosinophilia,
haemolytic anaemia, porphyria

Rare: Hypersensitivity reactions
including anaphylaxis
Not Known: There have also been
reports of: Anaphylactoid purpura,
hypotension, dyspnea, serum
sickness, peripheral oedema,
tachycardia, anaphylactic shock,
anaphylactoid reactions, exacerbation
of systemic lupus erythematosus,
Jarisch-Herxheimer reaction (see
section 4.4).

Endocrine disorders:

Not Known: Brown-black
microscopic discolouration of
thyroid tissue has been reported
with long-term use of tetracyclines.
Thyroid function is normal.

Nervous system disorders:
Not Known: Bulging fontanelle in
infants and benign intracranial
hypertension in juveniles and adults
have been reported in some individuals
receiving full therapeutic dosages of
tetracyclines. These are reversible on
stopping the drug. Symptoms include
blurring of vision, scotomata and
diplopia. Permanent visual loss has
been reported.

Cardiac disorders:

Rare: Pericarditis

Gastrointestinal disorders:

Not Known: Abdominal pain,
nausea, vomiting, diarrhoea, anorexia,
discolouration of teeth and enamel
hypoplasia (usually after long term
use), glossitis, dysphagia, oesophagitis
and oesophageal ulceration have been
reported most often in patients
administered the hyclate salt in capsule
form. Most of these patients took
medication just prior to going to
Stomatitis, dyspepsia.

Hepatobiliary disorders:

Rare: Hepatotoxicity,
transient increases in liver function
tests, hepatitis, jaundice,
hepatic failure and pancreatitis have
been reported rarely.

Skin and subcutaneous tissue

Rare: Exfoliative dermatitis,
angioneurotic oedema, StevensJohnson syndrome, urticaria.
Not known: Rashes including
maculopapular and erythematous
rashes, skin photosensitivity (see
section 4.4), photo-onycholysis,
erythema multiforme, toxic
epidermal necrolysis.

Musculoskeletal, connective tissue and
bone disorders:

Not known: Arthralgia, Myalgia.

Renal and urinary disorders:

Not known: Increased blood urea.

Ear and labyrinth disorders:

Not known: Tinnitus.

Reproductive system and breast

Not known: Vaginitis.

Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal
product is important. It allows continued monitoring of the benefit/risk
balance of the medicinal product. Healthcare professionals are asked to
report any suspected adverse reactions via the Yellow Card Scheme at:


Acute over dosage with antibiotics is rare. In the event of over dosage
discontinue medication. Gastric lavage plus appropriate supportive
treatment is indicated.
Dialysis does not alter serum doxycycline half-life and thus would not be of
benefit in treating cases of overdose.




Pharmacodynamic properties

Pharmacotherapeutic group: tetracyclines, ATC code: J01AA02

Doxycycline 100 mg is primarily bacteriostatic and is believed to exert its
antimicrobial effect by the inhibition of protein synthesis. Doxycycline 100 mg is
active against a wide range of Gram-positive and Gram-negative bacteria and certain
other micro-organisms.
Mechanism of action
The main mechanism of action of doxycycline is on protein synthesis. Doxycycline
passes directly through the lipid bilayer of the bacterial cell wall and an energy
dependent active transport system pumps the drug through the inner cytoplasmic
membrane. Once inside the cell doxycycline inhibits protein synthesis by binding to
30S ribosomes and prevents the addition of amino acids to the growing peptide chain.
Doxycycline will impair protein synthesis in mammalian cells at very high
concentrations but these cells lack the active transport system found in bacteria.

Pharmacokinetic properties
Doxycycline is almost completely absorbed and is not subject to presystemic
metabolism, the mean bioavailability being approximately 93%.
Tissue distribution is good and Doxycycline has a strong affinity for renal and lung
tissue. Plasma protein binding is in the range 82-93% and Doxycycline is transferred
into breast milk. The volume of distribution for doxycycline ranges from 0.9-1.8 lkg1 and the plasma half life ranges from 18-22 hours.
No significant metabolism occurs.
Doxycycline is cleared intact by renal and biliary mechanisms.


Preclinical safety data
Not applicable


List of excipients
Sucrose and maize starch microgranules,
Titanium dioxide (E171)
Indigo carmine (E132)
Yellow iron oxide (E172)
Black iron oxide (E172)


Not applicable


Shelf life
3 years


Special precautions for storage
None stated


Nature and contents of container
Doxycycline capsules are packed in blister packs made of one sheet of 200 micron
rigid, opaque white polyvinyl chloride and a second sheet of 20 micron aluminium.
Pack sizes are: 8, 10 and 50 capsules. Not all pack sizes may be marketed.


Special precautions for disposal
No special requirements.


Crescent Pharma Limited
3&4 Quidhampton Business Units
Polhampton Lane
RG25 3ED


PL 20416/0460





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