Health Q&A: garlic capsules mixed with medication and ANCA tests explained

Dr David Roche / 29 November 2012

Saga Magazine's Dr David Roche looks at the possible effects of garlic capsules when combined with prescription medication and explains ANCA blood tests to a reader

Question: Could garlic capsules (1000mg) have a negative effect on the prescribed medication I am currently taking following a heart attack? The list includes aspirin and thyroxine as well as a calcium channel blocker, a statin, beta blocker and an ace inhibitor.

Answer: The only potential cause for concern is the interaction of garlic and aspirin. Combining the two is known to increase the blood thinning properties of aspirin, potentially exacerbating side effects such as easy bruising and nose bleeds which some people experience on aspirin anyway. The recommendation is that you should avoid large intakes of garlic while on aspirin but your daily 1000mg capsule is unlikely to be significant. However, watch out for any troublesome bleeding and if it occurs, stop the garlic. I have checked various databases and not found any other relevant interactions, but it would be worth double-checking this with your pharmacist or GP as different members of the same drug group (statins for example) can interact with other drugs in different ways.

Question: My uncle recently had an ANCA blood test and his GP said it was to do with antibodies; the result was PR3 titre of 3.1. What does this mean?

Answer: ANCA (antineutrophil cytoplasmic antibody) tests are used to identify people who may be suffering from vasculitis or diseases that can cause it. Vasculitis is a process of inflammation in the walls of blood vessels and can occur at many different sites in the body. The consequences can be very serious, causing organs to fail if it is uncontrolled, but fortunately it is not that common. These diseases responsible are triggered by when the immune system turns on itself and produces antibodies (autoantibodies) which damage the body. ANCA is one of these autoantibodies and PR3 is a subdivision of it. The number of antibodies circulating is measured by a titre which is expressed as a ratio; 3:1 is a good result, indicating that not many antibodies are present, though they have been detected. A result of 64:1 for example, would indicate a high level of antibodies.

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