Ivermectin (Stromectol) for typical and crusted scabies This Medicine Update is for people who are taking, or thinking about taking, ivermectin to treat typical or crusted scabies. Summary Ivermectin (Stromectol) is a medicine that can help to cure scabies infections. It may be prescribed when other treatments have not worked, or cannot be used. It is in tablet form. Taking two doses of ivermectin can cure typical scabies in most people. Ivermectin is also recommended as part of the treatment for a more severe form of scabies called crusted scabies. Ivermectin treatment for typical and crusted scabies may fail if doses are not taken as instructed. The scabies mite can become resistant to ivermectin if the medicine is not taken as instructed. Do not share your ivermectin dose with other people, even if they might have scabies too. Itching can continue after taking ivermectin this does not mean the treatment has failed. Common side effects of ivermectin include tiredness stomach cramps, rash, dizziness, headache or joint pain (see section 5: What are the side effects of ivermectin?) Online version at nps.org.au/publications/consumer/medicine-update/ 2014/ivermectin-stromectol-for-scabies Date published: August 2014 Independent, not-for-profit and evidence based, NPS MedicineWise enables better decisions about medicines and medical tests. We receive funding from the Australian Government Department of Health.
Contents section What is ivermectin (Stromectol)?...1 What is scabies?... 2 How does ivermectin treat scabies?... 3 How effective is ivermectin?... 4 What are the side effects of ivermectin?... 5 Who shouldn t take ivermectin?... 6 What other medicines are available for the treatment of scabies?... 7 How to take ivermectin... 8 What else should I know about ivermectin?... 9 Other ways to help manage scabies...10 Can I get ivermectin through the PBS?...11 For more information...back page Asking the right questions about new medicines What is Medicine Update? Medicine Update provides independent information about new medicines and new listings on the PBS. It tells you about the possible benefits and risks of new medicines, who can and can t use them, and some of the other treatment options available. How to use Medicine Update Medicine Update is a tool to help you understand your treatment choices and to discuss them with your health professional. Medicine Update doesn t describe all possible side effects, precautions, or interactions with other medicines so you should always read the consumer medicine information (CMI). Who is it for? Medicine Update is for anyone who is starting this medicine, or thinking of starting it, and their carers. Where does Medicine Update come from? Medicine Update is written by NPS MedicineWise in consultation with consumers and health professionals. NPS MedicineWise is an independent, non-profit, government funded organisation. 2014 National Prescribing Service Limited (NPS MedicineWise). Reasonable care is taken to provide accurate information at the time of creation. This information is not intended as a substitute for medical advice and should not be exclusively relied on to manage or diagnose a medical condition. NPS MedicineWise disclaims all liability (including for negligence) for any loss, damage or injury resulting from reliance on or use of this information. 2
1. What is ivermectin? Ivermectin (pronounced eye-ver-mek-tin) is the active ingredient in a prescription medicine with the brand name Stromectol. 1 Ivermectin is a scabicide a product that is used to treat a skin infection caused by tiny mites, called scabies. 1 Ivermectin can be prescribed to treat scabies when other medicines have not been successful, or when the other available medicines cannot be used. 1 It is also part of the treatment for a more severe form of scabies called crusted scabies (or Norwegian scabies). 1 Ivermectin is also used to treat parasitic worm infections, including river blindness (onchocerciasis) and strongyloidiasis. 1 The active ingredient is the chemical in the medicine that makes the medicine work. The brand name (the name the medicine is sold under) is given to the medicine by the manufacturer. Some medicines are available under several different brand names. 3
2. What is scabies? Scabies is a highly contagious skin infection caused by a very small parasite a mite called Sarcoptes scabiei that burrows into the top layers of skin to lay eggs. 2 Scabies is contagious Scabies mites need about 20 minutes of skin-to-skin contact (including sexual contact) to transfer from one person to another. 2 In general, mites do not survive away from human skin. However, in unusual circumstances mites can survive for 24 36 hours away from the human body. 3 The risk of catching scabies after coming into contact with clothing, bed linen or furnishings that have been in contact with an infected person is very low (see section 10: Other ways to help manage scabies). 2 4 You cannot catch Sarcoptes scabiei from animals. Symptoms include itch and rash The most common and obvious symptom of a scabies infection is an itchy rash, which tends to be worse at night. 2,5,6 The rash is not always easy to see. It can take up to four weeks for symptoms like rash or itch to occur after first being infected with scabies. 2,5,7 This delay is more common in someone who has never had scabies before. 7 For people who may have had previous scabies infections, symptoms tend to show up more quickly after one or two days. 5,7 People with scabies but no symptoms can still pass the infection on to others. 6 Scabies most often affect areas of the body where the skin is thinnest, such as in the webbing between fingers and other body parts that have skin creases and folds, such as wrists, armpits, buttocks, breasts and genitalia. 3 In babies, young children and the elderly, the palms, soles, face and the scalp can also be affected. 5 Other signs of a scabies infection 2 include: small sores where the mites have burrowed into the skin small, clear, fluid-filled spots. Typical and crusted Typical scabies is the name given to the more common type of scabies infection. A person with typical scabies will have between 5 and 50 mites. 2 Sometimes scabies infection is very severe, with thousands of mites being present, causing the skin to scale badly and form crusts. 2 This condition called crusted scabies tends to occur in people whose immune system is not working well, such as transplant patients on immunosuppressive therapy, people who misuse alcohol, or people with weak or low immunity, (eg, leprosy, HIV). 3 Crusted scabies is extremely infectious, and can be life-threatening. Complications of scabies If scabies remains untreated, further problems can develop. For example, as the itching is often worse at night time, a person with scabies can find themselves feeling constantly tired because of poor sleep. Also, constant scratching increases the chances that sores can become infected with bacteria that go on to cause bacterial infections of the skin like impetigo 5 and acute rheumatic fever, as well as kidney problems. 8 When this occurs, antibiotics to treat these secondary infections may be needed. 4
3. How does ivermectin treat scabies? Ivermectin is thought to affect the nervous system of certain parasites. The effect of ivermectin is muscle paralysis and eventually death of the parasite. 8 10 Ivermectin has no effect on the nervous system of humans. 8 4. How effective is ivermectin? Ivermectin can kill live scabies mites, but has no effect on unhatched mite eggs. 9 People with typical scabies need two doses of ivermectin. The second dose is taken about one week after the first dose to treat any newly hatched mites. 9 A clinical trial is a research study conducted with patients. It compares one treatment with one or more other treatments, to assess its effectiveness and safety. Most people that take their two doses as directed will be cured of scabies. Crusted scabies is a more severe infection and is harder to treat. Ivermectin is an important part of treatment for this condition, and is used in combination with topical antiscabies medicines. Other medicines are also applied to the skin to help soften the scaling and crusts. 11 With crusted scabies, the number of ivermectin doses that need to be taken will depend on the severity of the infection. 11 Topical medicines are first choice in typical scabies In Australia, typical scabies is first treated with anti-scabies creams or lotions that go on the skin (topical). 11 These are applied on two occasions, one week apart. The most commonly used topical medicine is permethrin 5% cream. If permethrin hasn t worked, or the person is allergic to permethrin, another medicine call benzyl benzoate 25% lotion can be used. However, it can be more irritating than permethrin. 11 These topical medicines can be purchased from a pharmacy without a prescription. When applied correctly, these lotions have very high cure rates and are considered to have good safety in children and adults. 2,11 In clinical trials, permethrin has been shown to be more successful than ivermectin in curing typical scabies infection. 5,9 When a single application of the cream is compared with a single dose of ivermectin, permethrin has a better cure rate. 5,9 This is probably because the cream can kill unhatched as well as live mites, unlike ivermectin. 5
5. What are the side effects of ivermectin? Ivermectin, like all medicines, has possible side effects, although not everybody will experience them. As well as possible risks, medicines also have benefits. When you are recommended a medicine, it s good to ask your health professional questions that can help you understand and weigh-up what those risks and benefits might be. Ivermectin has been used for many years to treat parasitic infections and most people who have taken it have had no side effects, or only mild side effects that are most likely caused by the death of the parasite. 8 If you notice any of the side effects listed below and feel worried about them, or notice other signs or symptoms that are making you unwell, let your health professional know as soon as possible. Possible side effects for ivermectin that affect around 1 in every 100 people who take the medicine include: 1 itch after treatment dizziness headache joint pain loss of appetite rash stomach discomfort tiredness. Some of the side effects reported by people taking ivermectin for the treatment of scabies are likely to have been caused by the immune system reacting to the dead mites, rather than a true reaction to the medicine. 1 For example, it is common for the skin to feel itchy for up to 14 days after taking a dose of ivermectin or one of the topical preparations. 1 This is not a sign that the medicine has failed. Make sure you take the full number of doses, on the correct days, as prescribed by your doctor or nurse. The consumer medicine information (CMI) is another source of information about side effects for prescription (and some non-prescription) medicines. The CMI for ivermectin (Stromectol) contains a complete list of side effects, many that have only been reported in very low numbers. You can download the CMI for your medicine at nps.org.au/medicines, or ask your health professional for it. If you take ivermectin and have any of the following side effects, immediately have someone call 000 for an ambulance or go to the Emergency Department at your nearest hospital: any symptoms or signs of severe allergy such as swelling of the face, mouth, tongue or throat, sudden onset of breathing difficulty, wheezing or feeling faint, itchiness or skin rash. Learn how to make wise choices about taking medicines at nps.org.au/be-medicinewise Read more about side effects at nps.org.au/side-effects People with questions about their medicines or seeking general information about side effects can call NPS Medicines Line on 1300 633 424. To report possible side effects call the Adverse Medicine Events (AME) Line on 1300 134 237. Both these services are available Monday to Friday, 9am to 5pm AEST for the cost of a local call (calls from mobiles may cost more). 6
6. Who shouldn t take ivermectin for scabies? There are a number of groups where the efficacy (does it work), effectiveness (how well does it work) and safety of ivermectin for scabies is unknown, or has very little information available: children weighing less than 15 kilos 1,8 women who are pregnant or breastfeeding. 1,8 For these people, the topical medicines permethrin or benzyl benzoate are used. 2,11 In addition, if someone has an allergic reaction to ivermectin they should not continue with any further doses. 1 It is important that all your health professionals know your full medical history and are aware of all the medicines you take including those you buy without a prescription from a pharmacy, supermarket or the internet, and any complementary medicines (including natural or herbal medicines, vitamins and minerals). As well as the active ingredient(s), medicines contain other ingredients known as excipients or inactive ingredients. Excipients are ingredients such as fillers, binders or coatings. For most people, inactive ingredients won t matter. However, if you have particular allergies or intolerances, or avoid certain substances for cultural or medical reasons you may need to know what excipients are in your medicine. You can find a list of excipients under inactive ingredients in the consumer medicine information (CMI). 7
7. What other medicines are available for the treatment of scabies? Ivermectin is the only oral medicine currently available for treating scabies. All other scabicides are creams or lotions that need to be applied to the skin (ie, topical medicines). Topical treatments are used first In Australia, permethrin 5% cream is the most commonly recommended treatment for typical scabies. 2,9,11 It can be bought from the pharmacy and is considered safe to use in most age groups. 11 If permethrin is unsuitable or has not worked, benzyl benzoate 25% is another topical lotion that can be used. This lotion needs to be diluted before it can be applied to children younger than 12 years. 11 Ivermectin is used when topical treatments fail or cannot be used If these topical treatments do not cure the scabies, or cannot be used (eg, skin is inflamed, raw or weeping) then oral ivermectin may be prescribed. 1 Ivermectin is part of the treatment plan for crusted scabies. 1 A topical medicine such as permethrin will be used at the same time. Treatment for crusted scabies will also usually include a medicine that can be applied to the skin to help soften the scaling and crusts on separate days to when the topical scabicide is applied. Other medicines may be used during the treatment of scabies to help reduce the rash and itch such as moisturisers, topical corticosteroids, crotamiton cream or antihistamines. 12 If a secondary bacterial infection occurs (see Complications of scabies), then antibiotics might also be prescribed. 8
8. How to take ivermectin Ivermectin is a medicine that comes in tablet form. Tablets should be taken with food 8, and swallowed whole with a full glass of water. The number of tablets that make up a dose will be different for each person because a dose is based on how much you weigh. 13 Dose Make sure you follow the instructions given to you by your doctor or nurse. Take the tablets exactly as instructed. Do not swallow more tablets than you have been prescribed. Taking an extra dose will not provide any extra benefit and can put you at risk of side effects. If you take fewer tablets than instructed, the medicine may not work, and your scabies infection will not get better. Do not stop taking your medicine Sometimes people find their itch becomes worse after they take a dose of ivermectin. 1 This does not mean the medicine has failed. Continue to take your other doses as instructed. As the mites die they can make you feel more itchy than usual. Speak with your doctor or nurse if the itch is uncomfortable, as there are treatments that can help. If you take too much If you think you may have taken an overdose of ivermectin, or any other medicine, you should contact a health professional or call the Poisons Information Centre (13 11 26) for advice. You can also go the nearest hospital Emergency Department. Do not wait for signs of a problem, get help immediately. 9
9. What else should I know about ivermectin? Do not share your medicine with other people To give yourself the best chance of recovery from scabies, you should not share your medicine with anyone else even if they have the same condition as you. Ivermectin should be taken exactly as instructed by the doctor or nurse who prescribed the medicine. There is a growing concern that scabies mites could become less susceptible to the effects of ivermectin (this is called resistance) if the medicine is taken at the wrong dose or is taken by a person who does not have diagnosed scabies. Store ivermectin away from heat and moisture Keep your ivermectin tablets in the aluminium blister pack until you are going to take them. Tablets that are left out of the box, or outside of the blister pack, can be damaged and may not work as well. Keep ivermectin tablets in a dry and cool place. Do not place them near a sink, on a windowsill or in a car. Heat and dampness can destroy some medicines. Keep medicines out of reach and sight of children Children are curious and love to copy adults. Make sure you keep all your medicines, including ivermectin, safely out of reach and out of sight of children. Store medicines at least 1.5 metres (five feet) above floor level, preferably in a cupboard secured with a child-proof latch. If you keep medicines in a prominent place as a reminder of when to take them, try using a note instead, or if you have a smart phone try setting an alarm using the free NPS MedicineList+ smartphone app. Find out more at nps.org.au/medicinelist-plus Leftover and old medicines If you have a medicine that you did not finish, or that is out of date, hand it back to your pharmacist, nurse or doctor. Medicines that are past their use-by date may not work properly, and could cause an unwanted side effect if you, or someone else, take them. In the past, people often flushed unwanted medicines down the sink or toilet, or put them in the rubbish to be taken to the tip. Getting rid of medicines in these ways can damage the environment, and there is also the risk a child or animal could end up with accidental poisoning. 10
10. Other ways to help manage scabies In addition to topical or oral anti-scabies medicines, there are other practical actions that a health professional may recommend to help treat a scabies infection and prevent future infections from occurring. Co-ordinate treatment Because scabies is so contagious, people who have been in contact with an infected person may need to be treated with topical medicines even if they show no symptoms. If treatment of contacts is recommended by your health professional, try to treat everyone at the same time, as this gives the best chance of breaking the cycle and preventing a new infection. 2,14 People with diagnosed scabies need to repeat their treatment (topical or oral) one week after the first treatment, or as advised by their healthcare professional. 2,14 Treat clothing and bedding In some cases of scabies, there may be a need to wash clothes and bed sheeting. Alternatives are to place items in the sun for a number of days, 14 or to store bedding, shoes and clothing in a tightly sealed bag for at least three days. 2,9 Your health professional will tell you if this is necessary. Depending on the level of infection, it may also be necessary to vacuum carpets, rugs and any furniture that is covered in material that an infected person has been sitting on. 11
11. Can I get ivermectin through the PBS? In Australia, many of the medicines prescribed by a doctor or nurse practitioner are covered on the Pharmaceutical Benefits Scheme (PBS). 15 This means the amount you pay at the pharmacy for a particular medicine may be less than the full price, because the medicine has been subsidised by the Australian Government. The amount paid is known as the co-payment. People who are an Australian citizen and have a current Medicare card are able to receive PBS-listed medicines at the subsidised price. Medicines are listed on the PBS for the treatment of specific conditions. If you are prescribed a medicine for a condition that is not listed on the PBS you will need to pay the full price at the pharmacy. The cost may vary between pharmacies. Ivermectin (Stromectol) is listed on the (PBS) for the treatment of typical scabies, when other treatments have been tried first but have not worked, or when a person cannot use the other anti-scabies medicines available. Ivermectin is also listed on the PBS for use in the treatment of crusted scabies. It can be prescribed by a doctor or nurse practitioner. Cost to the individual You may be eligible to buy ivermectin through the PBS if one of the following applies to your situation: you have an allergy to the active ingredients in other scabies medicines you have a skin condition that prevents the use of topical scabies medicines topical scabies medicines have been tried and have not worked you have been diagnosed with crusted scabies. For a PBS-listed medicine, the maximum amount you would need to pay (ie, the co-payment) is: $36.90 for people without a concession card $6.00 for concession card holders. Cost to the Government The full cost to the Australian Government of a single treatment of ivermectin is: $54.54 for two (2) packs containing 4 tablets each. Each prescription is for a single treatment. 12
For more information Read the consumer medicine information (CMI) leaflet for ivermectin (Stromectol) to find out more about: who should not use it how to take the it most of the possible side effects the ingredients. You can get the CMI leaflet for ivermectin from: your health professional NPS MedicineWise (at nps.org.au/medicines) Merck Sharp & Dohme (Australia), the makers of ivermectin (Stromectol) on 1800 818 553 Monday Friday, 9am 4:30pm or via their website (at msd-australia.com.au) Information over the phone To get information about ivermectin (or any other prescription medicine) call the NPS Medicines Line on 1300 MEDICINE (1300 633 424) from anywhere in Australia for the cost of a local call (excluding mobiles). The service is available Monday Friday, 9am 5pm AEST (except NSW public holidays). To report a side effect with ivermectin Call the Adverse Medicine Events (AME) Line on 1300 134 237 (Monday Friday, 9am 5pm EST). The AME Line lets you report and discuss side effects that might be related to your medicine. Medicine-related side effects are then reported to the Therapeutic Goods Administration (TGA) for assessment and contribute to national medicine safety efforts. Your personal information will remain confidential and your privacy maintained. More about using medicines wisely Learn how to make wise choices about taking medicines at nps.org.au/be-medicinewise Read more about side effects at nps.org.au/side-effects References References available online at nps.org.au/publications/consumer/medicine-update/2014/ivermectin-stromectol-for-scabies Date published: August 2014 Independent, not-for-profit and evidence based, NPS MedicineWise enables better decisions about medicines and medical tests. We receive funding from the Australian Government Department of Health. 2014 National Prescribing Service Limited. This work is copyright. You may download, display print and reproduce this work in unaltered form only (retaining this notice) for non-commercial use either personally or within your organisation. Apart from any such use or otherwise as permitted under the Copyright Act 1968, all rights are reserved. Queries concerning reproduction and rights should be sent to copyright@nps.org.au. ABN 61 082 034 393 l Level 7/418A Elizabeth Street Surry Hills NSW 2010 l PO Box 1147 Strawberry Hills NSW 2012 Phone: 02 8217 8700 l Fax: 02 9211 7578 l email: info@nps.org.au l web: www.nps.org.au