Doxycycline
Brand names Cyclodox, Demix, Doxylar, Nordox, Ramysis, Vibramycin.
Used in the following combined preparations None
Doxycycline belongs to the tetracycline group of antibiotics. Longer acting than some other drugs in this group, it is used mainly in the treatment of urinary and respiratory tract infections, and infections of the skin, eye, prostate, and gastrointestinal tract. It is often used in the treatment of acne, and may be recommended for prevention of malaria in some parts of the world .
Doxycycline is less likely to cause diarrhoea as a side effect than other tetracyclines, and absorption of the drug is not significantly impaired by food. It can therefore be taken with meals to reduce side effects such as nausea or indigestion. It is also safe (unlike other tetracyclines) for people with impaired kidney function. Like other tetracyclines, doxycycline can cause staining of developing teeth and may affect bone development; it is therefore usually avoided in young children or pregnant women.
Information for Users
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets, capsules.
Frequency and timing of doses
1-2 x daily with water in a sitting or standing position.
Dosage range
100-200mg daily.
Onset of effect
4-12 hours’, several weeks (acne).
Duration of action
Up to 24 hours; several weeks (acne).
Diet advice
None.
Storage
Keep in closed container in a cool, dry place out of the reach of children.
Missed dose
Take as soon as you remember. If your next dose is due within 6 hours, take a single dose now and skip the next.
Stopping the drug
Take the full course. Even if you feel better, the original infection may still be present and symptoms may recur if treatment is stopped too soon.
Exceeding the dose
An occasional unintentional extra dose is unlikely to be a cause for concern. But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.
Possible Adverse Effects
Adverse effects from doxycycline are rare, although some people may experience nausea, vomiting, or diarrhoea. Other rare adverse effects include rash, itching, and increased sensitivity of the skin to sunlight, which may cause a rash to develop.
Interactions
Oral anticoagulant drugs Doxycycline may increase the anticoagulant action of these drugs.
Penicillin antibiotics Doxycycline interferes with the antibacterial action of these drugs.
Antacids and iron preparations may impair absorption of this drug. Do not take within 2-3 hours of doxycycline.
Barbiturates, carbamazepine, and phenytoin All of these drugs reduce the effectiveness of doxycycline. The doxycycline dosage may need to be increased accordingly.
Oral contraceptives A slight risk exists of doxycycline reducing the effectiveness of oral contraceptives. Discuss with your doctor.
Quick Reference
Drug group Tetracycline antibiotic
Overdose danger rating Low
Dependence rating Low
Prescription needed Yes
Available as generic Yes
Special Precautions
Be sure to tell your doctor if:
You have a long-term liver problem.
You have previously suffered an allergic reaction to a tetracycline antibiotic.
You are taking other medications.
Pregnancy
Not usually prescribed. May discolour the teeth of the developing baby. Discuss with your doctor.
Breast-feeding
The drug passes into the breast milk and may lead to discolouration of the baby’s teeth and have other adverse effects. Discuss with your doctor.
Infants and children
Not recommended under 12 years. Reduced dose necessary for older children.
Over 60
No special problems. Dispersible tablets should be used because they are less likely to cause oesophageal irritation or ulceration.
Driving and hazardous work
No known problems.
Alcohol
No known problems, but avoid excessive amounts.
Prolonged Use
Not usually prescribed long term, except for acne.
