Acrivastine is an antihistamine medicine that relieves the symptoms of allergies.

It's used to treat hay fever, conjunctivitis (red, itchy eyes), eczema and hives (urticaria).

It's also used for reactions to insect bites and stings and for some food allergies.

Acrivastine is known as a non-drowsy antihistamine. It's less likely to make you feel sleepy than some other antihistamines.

Acrivastine is available on prescription. You can also buy it from pharmacies and supermarkets.

It comes as capsules. Sometimes it's combined with a decongestant called pseudoephedrine to unblock your nose and sinuses.

• It's usual to take acrivastine as you need it, up to 3 times a day.
• Acrivastine is classed as non-drowsy antihistamine, but some people still find it makes them feel quite sleepy.
• Common side effects include a dry mouth and dizziness.
• Do not drink grapefruit juice while you're taking acrivastine - it might make you more likely to get side effects.
• It's best not to drink alcohol while you're taking acrivastine as it can make you feel sleepy.
• Acrivastine is also called by the brand name Benadryl Allergy Relief. When it's mixed with pseudoephedrine, it's called Benadryl Allergy Relief Plus Decongestant. Some Benadryl products don't contain acrivastine, but a different antihistamine such as cetirizine.

Acrivastine capsules that you buy from pharmacies and supermarkets can be taken by adults under the age of 65, and children aged 12 years and over.

Acrivastine isn't recommended for people over 65 years old because very little research on the medicine has been done in this age group.

Talk to your pharmacist or doctor if you're over 65 and want to take acrivastine.

Acrivastine isn't suitable for some people. Tell your doctor or pharmacist if you:

• have had an allergic reaction to acrivastine or any other medicines in the past
• have an intolerance to or cannot absorb some sugars, such as lactose or sorbitol
• have kidney disease
• have epilepsy or another health problem that puts you at risk of seizures
• have a rare illness called porphyria
• are booked to have an allergy test - taking acrivastine may affect the results, so you might need to stop taking it a few days before the test

If you or your child have been prescribed acrivastine, follow your doctor's instructions about how and when to take it.

If you bought acrivastine from a pharmacy or shop, follow the instructions that come with the packet.

How much will I take?

Acrivastine comes as capsules (8mg). The usual dose in adults and children aged 12 years and over is 1 capsule 3 times a day.

When it's mixed with a decongestant, each capsule contains 8mg of acrivastine and 60mg of pseudoephedrine. The usual dose in adults and children aged 12 years and over is 1 capsule 3 times a day.

Do not take more than 3 acrivastine capsules, or 3 acrivastine mixed with pseudoephedrine capsules, in 24 hours.

How to take it

Acrivastine doesn't usually upset your stomach. You can take it whether you have eaten recently or not.

Swallow the capsules whole. Do not chew them.

Always take acrivastine capsules with a drink of water, milk or juice (but do not drink grapefruit juice with acrivastine as you may be more likely to get side effects).

When to take it

You may only need to take acrivastine on a day you have symptoms, such as if you have been exposed to something you're allergic to like animal hair.

Or you may need to take it regularly to prevent symptoms, such as to stop hay fever during spring and summer.

What if I forget to take it?

Take your forgotten dose as soon as you remember, unless it's nearly time for your next dose.

Do not take a double dose to make up for a forgotten dose. Do not take more than 3 capsules in 24 hours.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Acrivastine is generally very safe. Taking too much is unlikely to harm you. If you take an extra dose by mistake, you might get some of the common side effects.

If this happens or you're concerned, contact your doctor.

Like all medicines, acrivastine can cause side effects, although not everyone gets them.

Common side effects

The most common side effect of acrivastine is feeling sleepy and tired. This happens in more than 1 in 10 people. Talk to your doctor or pharmacist if this side effect bothers you or won't go away.

Other common side effects of acrivastine happen in more than 1 in 100 people.

Talk to your doctor or pharmacist if these side effects bother you or won't go away:

• dry mouth
• feeling dizzy

Common side effects of acrivastine mixed with pseudoephedrine happen in more than 1 in 100 people.

They include:

• difficulty sleeping
• seeing things that aren't there (hallucinations)
• rashes
• difficulty peeing in men - especially men with an enlarged prostate

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to acrivastine.

These aren't all the side effects of acrivastine. For a full list, see the leaflet inside your medicines packet.

What to do about:

• dry mouth - chew sugar-free gum or suck sugar-free sweets
• feeling dizzy - lie down until the dizziness passes, then get up slowly. Move slowly and carefully. Avoid coffee, cigarettes, alcohol and recreational drugs. If the dizziness doesn't get better within a couple of days, speak to your pharmacist or doctor.
• difficulty sleeping - avoid having a big meal, smoking, or drinking alcohol, tea or coffee in the evening. Try not to watch television or use your mobile phone before going to bed. Instead, try to relax for an hour before bedtime.
• seeing things that aren't there (hallucinations) - talk to your doctor about this
• rashes - if you develop a rash after starting this medicine, check with your doctor or pharmacist as you may need a different type of antihistamine
• difficulty peeing - relax when you try to pee. Don't try to force the flow of urine. If it doesn't happen, try again later. Talk to your doctor urgently if you can't pee at all.

Acrivastine isn't normally recommended during pregnancy.

A similar antihistamine called loratadine is normally used first because there's more information to say that it's safe.

Talk to your doctor about the benefits and possible harms of taking acrivastine. It'll also depend on how many weeks pregnant you are and the reason you need to take acrivastine.

Acrivastine and breastfeeding

There's not a lot of information on the use of acrivastine during breastfeeding, so it's best not to take it.

It's usually safe to take similar antihistamines called loratadine and cetirizine while you're breastfeeding.

But speak to your doctor before taking any antihistamine if your baby was premature, had a low birth weight, or has health problems.

Some medicines and acrivastine interfere with each other and increase the chances of you having side effects.

Check with your pharmacist or doctor if you're taking:

• midodrine, a medicine used to treat low blood pressure (hypotension)
• ketoconazole, a medicine to treat fungal infections
• erythromycin, an antibiotic
• ritonavir, a medicine used to treat HIV infection
• any medicine that makes you sleepy, gives you a dry mouth, or makes it difficult for you to pee - taking acrivastine might make these side effects worse

Acrivastine mixed with pseudoephinedrine (Benadryl Allergy Relief Plus Decongestant) interferes with lots of medicines. Check with your pharmacist or doctor before you take it.

Mixing acrivastine with herbal remedies and supplements

There might be a problem taking some herbal remedies and supplements alongside acrivastine, especially ones that cause sleepiness, a dry mouth, or make it difficult to pee.

Ask your pharmacist for advice.