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Microscope in the lab


Minocycline (also known as minocin) is an antibiotic therapy used to treat acne or bacterial infections. It’s being developed for people with relapsing MS and those with a first MS-like incident.

Current phase of trial:
phase 2/3

Find out more about minocycline

How does it work?

Minocycline is commonly used to treat bacterial infections including acne, respiratory and urinary tract infections.

It works by preventing the growth and spread of bacteria. Researchers have found that minocycline can be anti-inflammatory, which may help to reduce myelin damage in MS.

How is it taken?

Minocycline is taken as a tablet.

Latest research

The MinoCIS Trial - clinically isolated syndrome (CIS)

Results from this phase 2 trial were published in June 2017. Researchers found that taking 100 mg minocycline reduced the risk of conversion to MS within six months from 61% to 33.4% compared with placebo. However, the difference in risk of developing MS was not significant after two years. The treatment was reported to be safe and well tolerated.

Larger studies are needed to assess the long-term benefits of minocycline.

> Read more about this research

Earlier research

Phase 2 trials

A phase 2 trial tested minocycline as an add-on therapy to the licensed treatment Copaxone in 40 people with relapsing MS. Minocycline reduced new lesion development by 60%.

A second phase 2 trial that involved 305 people with relapsing MS was terminated in 2011. Researchers found that adding minocycline to beta interferon treatment had no benefits. It's worth noting that the study had a high dropout rate, which made it difficult to fully analyse the results.

What are the side effects of minocycline?


Common side effects in people treated with minocycline include diarrhoea, dizziness or lightheadedness, dental discolouration, sun sensitivity and fungal infections.

How does it compare with current treatments?

Minocycline has not yet been directly compared with other MS treatments.

When is it likely to be available?

Minocycline is currently licensed for other conditions but is not licensed for MS. Results from the phase 2 studies discussed above could encourage larger phase 3 trials. This process is likely to take several years – we will keep you updated on the progress of minocycline.