Lymecycline: acne treatment, side effects and cautions

Lymecycline is an antibiotic from the tetracycline family. The NHS lists acne as its main use and describes it as working by eliminating the bacteria involved in acne and infections. Because acne is a long-running problem, it is prescribed for a long course rather than the few days typical of an infection.

It is also licensed for chest infections, sinusitis, sexually transmitted infections and infections in and around the mouth. For those, the dose and length are set by the prescriber and differ from the acne pattern.

The NHS describes one capsule once a day, usually in the morning. Each capsule contains 408 mg of lymecycline, equal to 300 mg of tetracycline. Swallow it whole with water. You can take it with or after food if it upsets your stomach.

Expect patience. Some improvement can appear within a week, but it can take several weeks before the skin clears. Acne treatment generally needs at least 8 weeks; if you see no improvement after 2 months, speak to your doctor about alternatives rather than carrying on indefinitely.

• Missed dose: take it when you remember unless the next is close; do not double up.

• Overdose: one extra dose is generally harmless; call NHS 111 if you have taken more than one extra, and 999 if you feel seriously unwell, taking the packaging with you.

• For infections, follow the dose and length given on your label.

The NHS says most adults and children over 12 can take lymecycline. Tell the prescriber about earlier allergic reactions to it or to other medicines, kidney problems, liver problems, lupus and myasthenia gravis.

Pregnancy is a clear exception. The NHS says it is not recommended because it can affect teeth and bone development in the baby, and a different antibiotic can be prescribed. Tell the prescriber if you are pregnant or trying to conceive.

The NHS lists nausea, stomach pain, diarrhoea and headaches as common and usually mild. Taking the capsule with or after food and avoiding rich or spicy meals helps nausea. Paracetamol or ibuprofen are suitable for headaches.

Diarrhoea lasting more than 24 hours may reduce the contraceptive pill.

• Call NHS 111 or your doctor for dark urine, or yellowing of the skin or whites of the eyes, which can be a sign of liver trouble.

• Seek advice for extreme sensitivity to sunlight.

• Call 999 for anaphylaxis: swollen lips, mouth or throat, difficulty breathing, rash, confusion or collapse.

• Antibiotics can cause thrush, with redness or itching in the mouth or vaginal symptoms, so tell a pharmacist or doctor if you notice them.

Minerals reduce absorption, so the NHS asks you to mention antacids and products containing aluminium, bismuth, calcium, iron, kaolin, magnesium or zinc. It also names lithium, other antibiotics, quinapril, warfarin, diuretics such as furosemide, and the epilepsy medicines phenytoin and carbamazepine.

Retinoid-type acne medicines and vitamin A supplements, including isotretinoin, are on the list, which matters for acne because people often use several treatments at once. Tell the prescriber about everything you use.

The NHS says lymecycline may be acceptable while nursing a healthy infant for short-term use, under 3 weeks, though other medicines might be preferable. Watch for poor feeding, diarrhoea, vomiting, rash, oral thrush or irritability. There is no evidence it reduces fertility, but discuss it with your prescriber before conception.

Alcohol is allowed, and it does not stop any type of contraception working. Suspected side effects can be reported through the Yellow Card scheme.