Unidox Solutab®: composition and pharmaceutical form
Unidox Solutab® comes as tablets for the preparation of an oral suspension. One tablet contains 100 mg of doxycycline in the form of the monohydrate.
The tablet is stirred into at least 50 ml of water until the suspension is uniform and is drunk immediately after preparation, sitting or standing and well before going to bed — this reduces the risk of inflammation and ulceration of the oesophagus. It is recommended to take the suspension with food. The score line on the tablet is not intended for dividing the dose.
How Unidox Solutab® works
Doxycycline binds to the 30S subunit of the bacterial ribosome and thereby suppresses protein synthesis. The multiplication of the bacteria stops, which means the action of the medicine is bacteriostatic and not bactericidal.
The spectrum of action is broad: doxycycline is active against many Gram-positive and Gram-negative bacteria, including intracellular microorganisms. That is precisely why the medicine is used in infections caused by agents on which many other antibiotics have no effect.
Indications
Doxycycline is prescribed to adults and children in mild community-acquired pneumonia, including infections caused by atypical agents — Chlamydophila pneumoniae, Mycoplasma pneumoniae and Chlamydophila psittaci — and also in an exacerbation of chronic bronchitis.
Other indications are sexually transmitted infections of the genitourinary system: those caused by Chlamydia trachomatis, including uncomplicated infections of the urethra, the cervix and the rectum, non-gonococcal urethritis caused by Ureaplasma urealyticum, chancroid, granuloma inguinale and lymphogranuloma venereum; as an alternative agent, doxycycline is used in gonorrhoea and syphilis. Besides that, it is used in acne vulgaris when an antibiotic is needed, in cholera and as an adjunct in amoebic infection, in borreliosis, conjunctivitis caused by Chlamydia trachomatis, Q fever, rickettsioses, relapsing fever, plague, tularaemia, brucellosis, anthrax, ornithosis, leptospirosis and pasteurellosis, and also in malaria caused by chloroquine-resistant Plasmodium falciparum and for its prevention. In infections caused by Salmonella spp. tetracyclines are not used.
Method of use and dosage
The regimen for doxycycline differs from that of other tetracyclines, and exceeding the recommended dose increases the frequency of undesirable reactions. Adults and adolescents from 12 to 18 years with acute infections are given 200 mg on the first day, as a single dose or in two doses, and thereafter 100 mg a day; in more severe infections 200 mg a day is taken for the whole course. Treatment usually lasts 5–10 days and continues for at least another 24–48 hours after the symptoms and the fever have gone, and in infections caused by β-haemolytic streptococci for no less than 10 days, to prevent acute arthritis or glomerulonephritis.
| Indication | Scheme |
|---|---|
| Uncomplicated infections of the urethra, cervix and rectum caused by Chlamydia trachomatis, non-gonococcal urethritis | 100 mg twice a day, 7 days |
| Acute epididymitis and orchitis caused by Chlamydia trachomatis or Neisseria gonorrhoeae | 100 mg twice a day, 10 days |
| Primary and secondary syphilis | 200 mg twice a day, 2 weeks |
| Lymphogranuloma venereum | 200 mg a day, 21 days |
| Borreliosis | 200 mg a day, 14–21 days in the early stages, up to a month in the late ones |
| Prevention of anthrax after contact | 100 mg twice a day, 60 days |
Children
Children under 8 are not prescribed doxycycline because of the risk of permanent staining of the teeth. In children from 8 to 12 use is possible only when other medicines are unavailable, are likely to be ineffective or are contraindicated: at a body weight of up to 45 kg the starting dose is 4.4 mg per kg as a single dose or in two doses, then 2.2 mg per kg, and in severe infections up to 4.4 mg per kg for the whole course; at a weight above 45 kg the doses are the same as in adults. This pharmaceutical form does not allow a dose smaller than 100 mg to be measured out — in that case another doxycycline medicine is used.
Contraindications
The medicine is not prescribed in the following cases:
- hypersensitivity to doxycycline or to any excipient;
- hypersensitivity to other tetracyclines;
- the second and third trimesters of pregnancy;
- children under 8 — because of the risk of irreversible staining of the teeth;
- hereditary galactose intolerance, lactase deficiency or glucose-galactose malabsorption syndrome.
Special warnings and precautions
Inflammation and ulceration of the oesophagus have been described in people taking tetracyclines as tablets and capsules, so the medicine is washed down with plenty of water and taken sitting or standing. Skin reactions call for separate attention: bullous erythema multiforme (Stevens-Johnson syndrome), toxic epidermal necrolysis (Lyell's syndrome) and drug reaction with eosinophilia and systemic symptoms (DRESS) have been reported — with a severe skin reaction the medicine is withdrawn and appropriate treatment is given. Photodermatosis in the form of an excessive sunburn is possible: those who may find themselves in direct sunlight or under ultraviolet rays are advised to stop taking it at the first signs of reddening of the skin.
- with persistent diarrhoea and fever, pseudomembranous or staphylococcal colitis must be ruled out; agents that inhibit peristalsis are not given in that case;
- antibiotics promote the development of superinfection by insensitive microorganisms, including Candida; if it appears, the medicine is withdrawn;
- benign intracranial hypertension with irritation of the meninges and papilloedema has been described in adults: headache, blurred or double vision, nausea, vomiting, pulsating tinnitus, dizziness, pain behind the eye and photopsia — these phenomena are transient and usually disappear within days or weeks of the end of treatment;
- in patients with infections caused by spirochaetes a Jarisch-Herxheimer reaction may develop soon after treatment starts; as a rule it resolves on its own;
- tetracyclines can prolong the prothrombin time, so in clotting disorders the medicine is used with caution;
- caution is needed in impaired liver function and with the concomitant use of potentially hepatotoxic agents: there are no pharmacokinetic data in such patients;
- during prolonged treatment the blood counts and liver and kidney function are checked periodically and the medicine is stopped if they deviate from normal;
- prolonged use of tetracyclines can lead to a deficiency of B-group vitamins because the bacteria that produce them are suppressed, and also to microscopic brown-black changes in the colour of the thyroid gland without any disturbance of its function.
There is cross-resistance between doxycycline and other tetracyclines. The antianabolic properties of tetracyclines are capable of raising the blood urea level, but studies in patients with renal failure have shown that this does not apply to doxycycline.
Drug interactions
The absorption of doxycycline is impaired by metal ions that form inactive chelates with it: antacids containing aluminium, calcium or magnesium, iron preparations and bismuth salts. Activated charcoal and ion-exchange resins such as colestyramine also reduce absorption — they are taken 2–3 hours after doxycycline. Quinapril reduces absorption because of the high magnesium content of the tablet, and agents that raise the pH of the stomach contents worsen the uptake of tetracyclines, which dissolve better in an acid medium.
Doxycycline prolongs the prothrombin time and enhances the action of anticoagulants — their dose may have to be adjusted. Bacteriostatic medicines can weaken the bactericidal action of β-lactams, so concomitant use with penicillins is avoided. Enzyme inducers — rifampicin, barbiturates, carbamazepine, primidone, phenytoin, and also prolonged alcohol abuse — speed up the metabolism of doxycycline and shorten its half-life, which may make an increase in the daily dose necessary. The combination of tetracyclines with methoxyflurane can lead to fatal kidney damage. Doxycycline raises the concentration of ciclosporin, so they are combined only under strict medical supervision, and it enhances the glucose-lowering action of the sulfonylureas — blood glucose is monitored and the dose reduced if necessary. Taking it shortly before, during or after treatment with retinoids, for example acitretin or isotretinoin, carries the risk of a transient rise in intracranial pressure.
Pregnancy and breastfeeding
In the second and third trimesters of pregnancy doxycycline is contraindicated: its use causes permanent staining of the child's milk teeth and may slow bone growth. As a precaution it is recommended to avoid the medicine in the first trimester as well, although the data from a large number of such uses do not so far indicate an increased risk of congenital malformations. Tetracyclines cross the placenta; animal studies revealed an unfavourable effect on reproduction but not on the foetus.
Doxycycline should not be used while breastfeeding. Tetracyclines pass into breast milk, and their influence on the staining of the teeth and the slowing of bone growth in the child cannot be ruled out. The decision on whether to stop breastfeeding or the treatment is taken with the benefit of feeding for the child and of the therapy for the mother in mind. In rats, oral doxycycline had an unfavourable effect on fertility; there are no data on its effect on fertility in humans.
Adverse effects
The most frequent are reactions of the digestive system and fungal infections of the mucous membranes.
- common — nausea, inflammation of the vagina and other candidal infections, itching in the anal area, black tongue, stomatitis, inflammation in the genitourinary area;
- uncommon — headache, vomiting, diarrhoea, inflammation of the tongue;
- rare — abdominal pain, reduced appetite, tinnitus, pericarditis, flushes, haemolytic anaemia, thrombocytopenia, neutropenia, eosinophilia;
- rare — drug reaction with eosinophilia and systemic symptoms (DRESS), brown-black changes in the colour of the thyroid gland;
- very rare — hypersensitivity reactions, including anaphylactic shock, anaphylactoid reactions, angioedema, urticaria, breathlessness, a fall in blood pressure, serum sickness, peripheral oedema, tachycardia and an exacerbation of systemic lupus erythematosus;
- very rare — bulging fontanelle in infants, irritation of the meninges with papilloedema;
- frequency not known — prolongation of the prothrombin time, porphyria, Jarisch-Herxheimer reaction;
- severe skin reactions — Stevens-Johnson syndrome and toxic epidermal necrolysis, and also photodermatosis.
Overdose
Overdose shows itself as liver damage: vomiting, bouts of fever, jaundice, haematomas, tarry stools, azotaemia, raised aminotransferase activity and prolongation of the prothrombin time. In addition, an excessive dose can cause irritation and ulceration of the oesophagus with retrosternal pain, difficulty swallowing and oesophagitis — this is linked to the tablet sticking to the wall of the oesophagus, which can be avoided by washing the dose down with about 200 ml of water (in children about 125 ml).
Inducing vomiting is not recommended, so as not to injure the oesophagus. To reduce absorption, activated charcoal and laxatives are usually enough. Haemodialysis has no effect on the elimination of doxycycline. Treatment is symptomatic, with monitoring of the water and electrolyte balance.
How to get a prescription for Unidox Solutab® online
Antibiotics are dispensed on prescription, and prescribing doxycycline makes sense only in a confirmed bacterial infection: in viral illnesses it is useless and only increases the resistance of microorganisms.
During the online consultation the doctor will assess the symptoms, the allergy history and the medicines being taken, will choose the dose and the length of the course and, if there are indications, will issue an electronic prescription — the medicine can be collected from a pharmacy using its code.
