It should be continued daily during travel in the malarial areas and for 4 weeks after the traveller leaves the malarial area. Enamel hypoplasia has also been reported. Studies have shown no significant difference in the serum half-life of doxycycline in individuals with normal and severely impaired renal function.Haemodialysis does not alter the serum half-life of doxycycline. Researchers are unsure how much doxycycline will pass to the infant through breast milk.Doctors may prescribe short courses of doxycycline to a nursing parent. Bulging fontanelles in infants and benign intracranial hypertension in juveniles and adults have been reported in individuals receiving full therapeutic dosages of tetracyclines. This medicine may cause teeth discoloration in the children. Avoid administration of vaccine during treatment with doxycycline.Ergotamine and methysergide; There is an increased risk of ergotism when doxycycline is co-administered with ergotamine and methysergide.Methotrexate; Doxycycline increases the risk of methotrexate toxicity; prescribe with caution to patients on methotrexate.Kaolin and sucralfate may reduce the absorption of doxycycline.Quinapril contains magnesium carbonate and may interfere with the absorption of doxycyclineA few cases of pregnancy or breakthrough bleeding have been attributed to the concurrent use of tetracycline antibiotics with oral contraceptives.False elevations of urinary catecholamine levels may occur due to interference with the fluorescence test.Visual disturbances such as blurring of vision may occur during treatment with doxycycline and in such cases; patients must refrain from driving or operating machinery.The following adverse reactions have been observed in patients receiving tetracyclines, including doxycycline.Hypersensitivity reactions, including anaphylactic shock, anaphylaxis, anaphylactoid reaction, anaphylactoid purpura, hypotension, pericarditis, angioneurotic oedema, exacerbation of systemic lupus erythematosus, dyspnoea, serum sickness, peripheral oedema, tachycardia and urticaria.As with all antibiotics, overgrowth of non-susceptible organisms may cause candidiasis, glossitis, staphylococcal enterocolitis, pseudomembranous colitis (with Haemolytic anaemia, thrombocytopenia, neutropenia, porphyria, and eosinophilia have been reported with tetracyclines.Jarisch-Herxheimer reaction (Frequency Not known) (see Section 4.4)When given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discolouration of thyroid tissue. Bulging fontanelles in infants and benign intracranial hypertension in juveniles and adults have been reported in individuals receiving full therapeutic dosages of tetracyclines. Studies to date indicate that this anti-anabolic effect does not occur with the use of Doxycycline in patients with impaired renal function.The use of antibiotics may occasionally result in overgrowth of non-susceptible organisms including Candida.

Concomitant use should be avoided.Antibacterials inactivate oral typhoid vaccines. Abnormal hepatic function has been reported rarely and has been caused by both the oral and parenteral administration of tetracyclines, including doxycycline.Excretion of doxycycline by the kidney is about 40%/72 hours in individuals with normal renal function. Use doxycycline in paediatric patients aged younger than 8 years only when the potential benefits are expected to outweigh the risks in severe or life- threatening conditions (e.g. Concomitant use should be avoided.Antibacterials inactivate oral typhoid vaccines. Doxycycline may not be appropriate for everyone, especially during pregnancy. Studies to date indicate that this does not occur with the use of doxycycline in patients with impaired renal function.Haemodialysis does not alter the serum half-life of 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.Doxycycline should be administered with caution to patients with hepatic impairment or those receiving potentially hepatotoxic drugs. Studies have shown no significant difference in the serum half-life of doxycycline in individuals with normal and severely impaired renal function.Haemodialysis does not alter the serum half-life of doxycycline.