Guidance

Chemoprophylaxis

Updated 17 June 2026

Recommendations for antimalarials should be appropriate for the destination and tailored to the individual, taking into account possible risks and benefits to the traveller. As part of a stringent individual risk assessment it is essential that a full clinical history is obtained, detailing current medication, significant health problems and any known drug allergies. For a suggested risk assessment template see Appendix 2.

Given the possibility of antimalarials purchased in the tropics being fake or sub-standard (47), travellers should obtain the medication required for their chemoprophylaxis from a reputable source in the UK before they travel. UKMEAG advises those purchasing antimalarial drugs over the internet to ensure that they are dealing with a bona fide supplier or website.

Principles

Causal prophylaxis

Causal prophylaxis is directed against the liver stage of the malaria parasite, which takes approximately 7 days to develop (see life cycle in Figure 1 in Awareness of risk). Successful drug activity at this stage prevents the parasite from progressing to infect red blood cells.

Causal prophylactics need to be continued for approximately 7 days after infection (48), so UKMEAG recommends that they are continued for 7 days after leaving a malarious area (see Table 2).

It is important not to confuse liver-stage schizonts with hypnozoites. All 5 species of human malaria parasites have liver-stage schizonts, but only P. vivax and P. ovale have the hypnozoite stage, against which causal prophylaxis is not effective.

Suppressive prophylaxis

Suppressive prophylaxis is directed against the red blood cell stages of the malaria parasites. To prevent infection, suppressive prophylactic drugs should be continued for 4 weeks after leaving a malarious area (49) (see drug regimens in Table 2).

Prophylaxis against hypnozoites

P. vivax and P. ovale have a dormant stage called the ‘hypnozoite’. The hypnozoite remains dormant for months and then ‘wakes up’ to develop into a liver schizont. The dormant hypnozoite explains why attacks of vivax or ovale malaria can occur long after the end of chemoprophylaxis. This is not due to drug failure, as none of the prophylactic drugs currently advised by UKMEAG acts against the hypnozoite stage of P. vivax or P. ovale.

Primaquine is active against hypnozoites (present only in P. vivax and P. ovale) and is used in the treatment of these forms of malaria. It also has causal prophylactic activity against the liver stage schizonts of all malaria parasites of humans (50).

Primaquine is occasionally used for terminal prophylaxis, also known as presumptive anti- relapse therapy (PART), to eradicate hypnozoites of P. vivax and P. ovale in people returned from travel with no symptoms.

However, the routine use of primaquine for prophylaxis or terminal prophylaxis is not recommended by UKMEAG.

Primaquine is not licensed in the UK and practitioners considering the use of primaquine as a prophylactic agent should consult an expert centre (see Information resources).

Primaquine is an oxidant drug and can lead to significant haemolysis in G6PD-deficient individuals.

The drugs

The summaries of product characteristics (SmPCs) for each antimalarial agent contain the full prescribing information. The British National Formulary (BNF) covers some of the major aspects of the full prescribing information. The SmPCs and BNF should be consulted for prescribing information when recommending malaria chemoprophylaxis.

The BNF and BNFC are available in one app.

This section on individual drugs is not as detailed as that provided for prescribers in the SmPCs and BNF. In the sections that follow, some of the UKMEAG’s recommendations may not follow the SmPCs. In that situation we recommend following the UKMEAG recommendations.

This section should be read in conjunction with the chapters:

• Awareness of risk, which provides information on drug resistance
• Chemoprophylaxis, which provides details of recommended dose regimens
• Special groups and Special categories, which provide additional information on the use of antimalarial agents in special groups, including those with medical conditions (for example, pregnant and breastfeeding women and individuals with renal impairment) and those in special categories (for example, children and the elderly)

Note: Anybody from the UK, including members of the public, can report any suspected side effects from malaria medicines via the Yellow Card Scheme on the Medicines and Healthcare products Regulatory Agency (MHRA) website. Attacks of malaria that occur in individuals prescribed malaria prophylaxis should also be reported via this system as well as to the Malaria Reference Laboratory (MRL) (see the section on Notification in Diagnosis).

Keep all medicines out of the sight and reach of children. The following drugs are not listed in order of preference.

Chloroquine

Mode of action

Chloroquine is concentrated in the malaria parasite lysosome and is thought to act by interfering with malaria pigment formation, causing generation of a ferriprotoporphyrin IX-chloroquine complex which is highly toxic to the parasite.

Efficacy

Chloroquine-resistant falciparum malaria is now reported from all WHO regions except Central America north of the Panama Canal and the Island of Hispaniola (Haiti and the Dominican Republic). Chloroquine remains effective against most P. vivax, P. ovale, P. knowlesi and virtually all P. malariae.

Formulations and method of administration

Tablets contain 155 milligrams (mg) chloroquine base (equivalent to 250mg of chloroquine phosphate, see BNF); syrup contains chloroquine base 50 milligrams per 5ml (equivalent to 80mg per 5mL of chloroquine phosphate, see BNF). To be taken orally with food. Antacids (aluminium, calcium and magnesium salts) and adsorbents (for example, kaolin) may reduce the absorption of chloroquine, so they should be taken at least 4 hours apart.

Prophylactic regimen

Adult dose 310mg (2 tablets) weekly, starting one week before entering a malarious area, continuing throughout the time in the area and for 4 weeks after leaving the area.

Contraindications

Practitioners should consult the BNF and SmPC before prescribing.

Allergy to chloroquine or to any other ingredients of the formulation (tablet or syrup). Concomitant use with amiodarone (see SmPC)

Cautions

Practitioners should consult the BNF and SmPC before prescribing. Chloroquine is safe in all trimesters of pregnancy. Its major disadvantage is the relatively poor protection it gives in many geographical areas due to the presence of drug-resistant P. falciparum.

Chloroquine should not be used in those with a history of epilepsy.

The risk of epilepsy is higher in first-degree relatives of those in whom this condition has been diagnosed so it should be considered as part of risk assessment. Epilepsy in a first-degree relative may not contraindicate the use of an antimalarial but may influence the choice of drug. Therefore, a family history of epilepsy should be sought as part of the risk assessment.

Chloroquine may exacerbate myasthenia gravis.

Severe hypoglycaemia has occurred in individuals both with pre-existing diabetes and without.

Chloroquine and chloroquine-related drugs can exacerbate psoriasis and should be avoided in those with generalised psoriasis or a history of such. Travellers with mild psoriasis can consider chloroquine if they are aware of the possible risks. The benefit of chemoprophylaxis with chloroquine may outweigh the risk of exacerbation of psoriasis, but each case should be considered on an individual basis.

In long-term use, ophthalmological examination every 6 to 12 months should be considered after 6 years’ prophylactic usage, though the risk of retinopathy developing on prophylactic dosage is considered to be very low (51). See also the Long-term traveller section in Special categories.

Interactions

Practitioners should consult the BNF and SmPC before prescribing.

Chloroquine should not be used in those taking Zyban® (bupropion hydrochloride SR) as the chances of seizure may be increased.

Chloroquine may suppress the antibody response to pre-exposure intradermal human diploid cell rabies vaccine (52). This interaction is not seen when rabies vaccine is given intramuscularly (the currently recommended licensed mode of vaccination in the UK).

Side effects

Frequently reported side effects are gastrointestinal disturbances and headache. Convulsions and severe skin reactions have been reported. Chloroquine may cause itching, especially in persons of African descent.

Hydroxychloroquine

Hydroxychloroquine is usually used for the treatment of rheumatic diseases, in doses greater than those needed for malaria prevention. Individuals already taking hydroxychloroquine and for whom chloroquine would be an appropriate malaria chemoprophylactic agent, can remain on hydroxychloroquine and do not need to transfer to chloroquine. If doubt exists, seek expert advice.

Proguanil

Proguanil has been discontinued in the UK.

Both Paludrine (proguanil hydrochloride) and Paludrine/Avloclor (proguanil hydrochloride, chloroquine phosphate) Anti-Malarial Travel Pack have been discontinued in the UK, so proguanil is no longer available in the UK.

Supplies of Avloclor (chloroquine phosphate) and atovaquone plus proguanil combination preparation are not affected.

Mefloquine

As with any antimalarial, stringent risk assessment is required before advising mefloquine use.

Mode of action

Mefloquine’s mode of action has not been determined but is thought to be unrelated to that of chloroquine and not to involve an anti-folate action. It acts as a suppressive prophylactic.

Efficacy

The protective efficacy of mefloquine is 90% or more (53, 54). At the present time, significant resistance of P. falciparum to mefloquine is a problem only in some areas of South-East Asia (55) but is reported sporadically from the Amazon basin.

Formulation and method of administration

250mg tablets. Taken orally, preferably after a meal and with plenty of liquid.

Prophylactic regimen

Adult dose 250mg weekly, starting 2 to 3 weeks before entering a malarious area to assess tolerability, continuing throughout the time in the area and for 4 weeks after leaving the area.

Contraindications

Practitioners should consult the BNF and SmPC before prescribing. Contraindications include:

• allergy to mefloquine or to any ingredient of the tablets
• allergy to quinine or quinidine
• a current or previous history of depression generalized anxiety disorder, psychosis, schizophrenia, suicide attempts, suicidal thoughts, self-endangering behaviour or any other psychiatric disorder, epilepsy or convulsions of any origin. The risk of epilepsy and serious mental health disorders is higher in first-degree relatives of those in whom these conditions have been diagnosed so they should be considered as part of risk assessment. A condition in a first-degree relative may not contraindicate the use of an antimalarial but may influence the choice of drug. Please read in conjunction with the section on Epilepsy in Special risk groups
• a history of Blackwater fever
• severe impairment of liver function
• use with halofantrine; also, halofantrine should not be given within 15 weeks after the last dose of mefloquine
• mefloquine should not be used in those taking Zyban® (bupropion hydrochloride SR) as the chances of seizure may be increased

Use of a checklist should ensure that proper screening is undertaken prior to mefloquine administration, and these contraindications are followed (56). The BNF, the manufacturer’s SmPC, patient information leaflet and risk materials should also be consulted.

Cautions

Practitioners should consult the BNF and SmPC before prescribing.

Pregnancy and breastfeeding (see medical conditions in the Special risk groups section), cardiac conduction disorders. Not recommended in infants under 5kg.

The SmPC points out that during clinical trials, mefloquine was not administered for longer than one year and states that periodic checks on liver function and eye assessments should be performed if mefloquine is used for a prolonged period. Any person taking mefloquine presenting with a visual disorder should be referred to their treating physician as this may require stopping chemoprophylaxis.

In those who have suffered traumatic brain injury, the decision whether to advise mefloquine chemoprophylaxis should be made on an individual basis after a detailed risk assessment.

Diving and mefloquine

If the individual tolerates mefloquine prophylaxis, there is no evidence that they cannot physically perform underwater diving. However, mefloquine does lower the seizure threshold and its side effects could potentially be confused with decompression or narcosis events. It should also be noted that some sub-aqua centres do not permit those taking mefloquine to dive. Mefloquine might therefore be better avoided for those undertaking diving holidays, but there is no contraindication to its use in occasional divers who have taken and tolerated the drug before, or those able to start taking it early to ensure that no adverse events occur.

Pilots

The UK Civil Aviation Authority advises that mefloquine should not be administered to pilots, although there is no evidence that mefloquine impairs function.

The military

The UKMEAG recognises that malaria risk is different in military and civilian travellers. The Ministry of Defence has prepared guidelines for malaria prevention specific to military personnel. Civilian practitioners asked to provide malaria prevention advice for members of the Armed Forces should liaise with the Defence Medical Services via Defence Medical Services Public Health Unit at SG-DMed-Med-DPHU-GpMailbox@mod.gov.uk

Interactions

Practitioners should consult the BNF and SmPC before prescribing.

Side effects

Attention has focused on neuropsychiatric problems and vestibular disorders with mefloquine prophylaxis. Those taking mefloquine are more likely to have abnormal dreams, insomnia, anxiety and depressed mood during travel than those who take atovaquone-proguanil or doxycycline (57).

Increased neuropsychiatric adverse events have been found, especially in women using mefloquine, when compared with those receiving doxycycline, or atovaquone plus proguanil, but not those taking chloroquine plus proguanil (53, 58, 59). No association between mefloquine prescriptions and hospitalisation has been demonstrated (60). Dizziness, balance disorder, tinnitus and vertigo may occur. In a small number of patients, it has been reported that dizziness, vertigo or loss of balance may continue for months after discontinuing the drug.

The list of psychiatric symptoms that should be regarded as prodromal for a more severe event is: insomnia; abnormal dreams and/or nightmares; acute anxiety; depression; restlessness; and confusion.

Overall, mefloquine remains an important prophylactic agent which is tolerated by most travellers who take it (53, 57, 61).

Doxycycline

Mode of action

Doxycycline is lipophilic and acts intracellularly, binding to ribosomal mRNA and inhibiting protein synthesis. It acts as a suppressive prophylactic.

Efficacy

Doxycycline is of comparable prophylactic efficacy to mefloquine (62).

Formulations and method of administration

Capsules (50 or 100mg) or dispersible 100mg tablets.

The capsules and solution of dispersible tablets should be swallowed with plenty of fluid in either the resting or standing position and the recipient should not lie down for at least one hour after ingestion to reduce the likelihood of oesophageal irritation and ulceration. If gastric irritation occurs, it is recommended that doxycycline is taken with food or milk.

Studies indicate that the absorption of doxycycline is not notably influenced by simultaneous ingestion of food or milk.

The absorption of doxycycline may be impaired by concurrently administered antacids containing aluminium, calcium, magnesium or by oral zinc, iron salts or bismuth preparations. Intake of these substances should be separated from dosing with doxycycline as far as possible.

Prophylactic regimen

Dose 100mg daily, starting 1 to 2 days before entering a malarious area, continuing throughout the time in the area and for 4 weeks after leaving the area.

Contraindications

Practitioners should consult the BNF and SmPC before prescribing.

Allergy to tetracyclines or to any ingredients of the capsules or dispersible tablets. Children under 12 years of age.

Use during pregnancy is contraindicated in the SmPC. The UK National Teratology Information Service states that doxycycline is best avoided for antimalarial prophylaxis during pregnancy. However, if required before 15 weeks’ gestation it should not be withheld if other options are unsuitable (63). The course of doxycycline, including the 4 weeks after travel, must be completed before 15 weeks’ gestation.

Use while breastfeeding is contraindicated in the SmPC (64). A Centers for Disease Control and Prevention (CDC) Expert Meeting on malaria chemoprophylaxis stated that doxycycline is excreted at low concentrations in breast milk and that the American Academy of Pediatrics (AAP) assessed tetracycline as compatible with breastfeeding (65).

UKMEAG’s view is that other options are preferable in those who are breastfeeding but doxycycline can be used if other options are unsuitable.

Cautions

Practitioners should consult the BNF and SmPC before prescribing.

Hepatic impairment. Patients taking potentially hepatotoxic drugs. Renal impairment. Myasthenia gravis. Systemic lupus erythematosus. Candida infections may occur.

The prescriber should warn against excessive sun exposure (and advise on the correct use of a broad-spectrum sunscreen).

Interactions

Practitioners should consult the BNF and SmPC before prescribing.

The metabolism of doxycycline is accelerated by carbamazepine and phenytoin. For individuals taking either of these medications, try to advise another antimalarial. If not possible or acceptable to the traveller, increase the dose of doxycycline to 100mg twice daily and counsel regarding measures to minimise the risk of adverse events. Tetracyclines possibly enhance the anticoagulant effect of coumarins (for example, warfarin), and doxycycline may increase the plasma concentration of ciclosporin.

Doxycycline is a non-enzyme-inducing antibiotic. The Faculty of Sexual and Reproductive Healthcare and the BNF advise that for combined oral contraceptives and for progestogen only oral contraceptives additional precautions are not required when using non-enzyme-inducing antibiotics. However, if the traveller suffers vomiting or diarrhoea, the usual additional contraceptive precautions should be observed.

Possibly reduces the efficacy of oral typhoid vaccine if given simultaneously. Preferably should not be started within 3 days after the last dose of vaccine.

Side effects

See the BNF and SmPC for full details.

Doxycycline hydrochloride preparations have a low pH and may produce oesophagitis and gastritis, especially if taken on an empty stomach and/or just before lying down.

Doxycycline may cause photosensitivity which is mostly mild and transient (57, 66).

Doxycycline is a broad-spectrum antibiotic and may predispose to vaginal candidiasis (57, 65).

Atovaquone plus proguanil combination preparation

Mode of action

Atovaquone works by inhibiting electron transport in the malaria parasite’s mitochondrial cytochrome b-c1 complex, causing collapse in the mitochondrial membrane potential. This action is potentiated by proguanil and is not dependent upon conversion to its metabolite cycloguanil. Indeed, the combination remains effective in cycloguanil-resistant parasites (67). Atovaquone/proguanil prevents development of pre-erythrocytic (liver) schizonts (but not hypnozoites). It acts as a causal prophylactic agent, so needs to be continued for only 7 days after leaving a malarious area (67). It also has activity against the erythrocytic stages of malaria parasites and is useful for treatment.

Efficacy

Prophylactic efficacy against P. falciparum is 90% or more (69 to 77). There is less published data on protection against P. vivax, but data available indicate that atovaquone-proguanil is effective in the prevention of primary attacks of vivax malaria (76, 78). However, like chloroquine, mefloquine and doxycycline, it will not protect against hypnozoite-induced episodes of P. vivax or P. ovale malaria.

Formulations and method of administration

Tablets containing proguanil 100mg and atovaquone 250mg. Paediatric tablets containing proguanil 25mg and atovaquone 62.5mg. To be taken orally with food or a milky drink.

Prophylactic regimen

Adult dose one tablet daily starting 1 to 2 days before entering a malarious area, continuing throughout the time in the area and for 7 days after leaving the area. Paediatric dose is given in Table 5.

UKMEAG does not support use of an abbreviated atovaquone-proguanil prophylaxis regimen in travellers after leaving malaria-endemic areas (79).

Maloff Protect, a brand of atovaquone plus proguanil combination preparation is available to purchase from UK pharmacies, after previously only being available on prescription. They are available for adults aged over 18 weighing more than 40kg.

Contraindications

Practitioners should consult the BNF and SmPC before prescribing.

Allergy to proguanil or atovaquone or to any of the other ingredients in the tablets.

Renal impairment (avoid for malaria prophylaxis if eGFR is less than 30 mL/minute/1.73m²).

Cautions

Practitioners should consult the BNF and SmPC before prescribing.

The use of other agents, rather than atovaquone plus proguanil (AP) combination preparation, is usually advised in pregnancy. However, the UK Malaria Expert Advisory Group (UKMEAG) advises that if there are no other appropriate options, it may be used in pregnancy. The co-prescription of folic acid (5mg daily) is advised alongside AP if conception is planned and in all trimesters of pregnancy. This is particularly relevant for use in the first trimester because of a theoretical increased risk of neural tube defects related to the antifolate action. The individual components have shown no adverse effects on parturition (childbirth) or pre- and post-natal development and animal studies show no evidence for teratogenicity.

Folic acid 5mg daily should be taken for the length of time that atovaquone/proguanil is taken in pregnancy and also by those taking atovaquone/proguanil who are seeking to become pregnant.

Women who have taken AP inadvertently just prior to or during the first trimester should be advised that this does not constitute grounds to terminate the pregnancy, as no evidence of harm has emerged in data so far available (80, 81).

The UKMEAG advises that atovaquone/proguanil can be used when breastfeeding if there is no suitable alternative antimalarial.

Diarrhoea or vomiting may reduce the absorption of atovaquone.

Interactions

Practitioners should also consult the BNF and SmPC before prescribing.

The proguanil component may enhance the anticoagulant effect of warfarin so monitoring is required. The antifolate effect of proguanil is increased when given with pyrimethamine.

Plasma concentrations of atovaquone are reduced by rifabutin and rifampicin, most non- nucleoside reverse transcriptase inhibitors, boosted protease inhibitors of HIV, tetracycline and metoclopramide (possible therapeutic failure of atovaquone, avoid concomitant use).

Atovaquone interacts with some antiretroviral drugs. For up-to-date information and an interaction checker see the HIV Drug Interactions website.

No interactions are reported.

Side effects

Practitioners should consult the BNF and SmPC before prescribing.

The most frequent side effects are headache and gastrointestinal upsets.

Dosage tables

These drugs are not listed in order of preference. The preferred prophylaxis is determined by a full risk assessment for each individual traveller.

Table 2. Prophylactic regimens against malaria in adults in areas of chloroquine-resistant P. falciparum

Regimen	Dose for chemoprophylaxis	Usual amount for tablet (mg)
Mefloquine - for adults weighing 45kg or more. (For adults weighing less than 45kg, consult Table 3)	One tablet weekly	250
Doxycycline	One tablet or capsule daily	100
Atovaquone plus proguanil combination preparation - for adults weighing 40kg or more. (For adults weighing less than 40kg, consult Table 5, below)	One tablet daily	250 (atovaquone) plus 100 (proguanil)

Table 3. Doses of prophylactic antimalarials for children

Note: Weight is a better guide than age for children, so weight should be used for the purpose of children’s dosage calculation including children who are over or under weight.

Weight in kilograms	Chloroquine base 155mg	Mefloquine 250mg	Doxycycline 100mg
Under 6.0	0.125 dose ¼ tablet	[note 1]	Not recommended
6.0 to 9.9	0.25 dose ½ tablet	0.25 dose ¼ tablet	Not recommended
10.0 to 15.9	0.375 dose ¾ tablet	0.25 dose [note 2] ¼ tablet	Not recommended
16.0 to 24.9	0.5 dose 1 tablet	0.5 dose ½ tablet	Not recommended
25.0 to 44.9	0.75 dose 1½ tablets	0.75 dose ¾ tablet	The BNFC advises 100mg once daily from 12 years (body weight 25kg and above); 1 tablet
45 and over	Adult dose 2 tablets	Adult dose 1 tablet	Adult dose 1 tablet

Note 1: The SmPC for mefloquine indicates that it can be used for those weighing more than 5kgs. Therefore, mefloquine (0.25 dose, ¼ tablet) may be advised for children weighing 5 to 9.9kg.

Note 2: For mefloquine at this weight, 0.375 dose would be preferable, but cannot be safely provided by breaking the adult tablet.

Further important notes

Doxycycline is unsuitable for children under 12 years irrespective of their weight. Caution: In other countries tablet strength may vary. Atovaquone/proguanil paediatric dosage is given in Table 5.

Table 4. Table of doses by spoon or syringe [note 3][note 4][note 5] measures for chloroquine syrup (50 mg/5 ml)

Weight in kilograms	Number of 5ml measures (there is often a half size measure at the other end of the spoon)	Proportion of adult dose
Under 4.5	0.5 (2.5ml)	0.08
4.5 to 7.9	1.0 (5.0ml)	0.16
8.0 to 10.9	1.5 (2.5ml plus 5ml)	0.24
11.0 to 14.9	2.0 (2 x 5ml)	0.32
15.0 to 16.5	2.5 (2.5ml plus 2 x 5ml)	0.40

Note 3: chemists may dispense dosing syringes for child doses.

Note 4: these dose-steps are not the same as for chloroquine tablets, which differ from the syrup in chloroquine content. Chloroquine syrup contains 50mg chloroquine base in 5ml.

Note 5: if chloroquine syrup is required for a child weighing more than 16.5kg please follow the dosage regimen stated in the BNFC.

Table 5. Table of paediatric doses of atovaquone/proguanil

Weight in kg	Proportion of adult dose	Number of paediatric tablets
5 to 7.9	0.125	½ paediatric
8 to 9.9	0.188	¾ paediatric
10 to 19.9	0.25	1 paediatric
20 to 29.9	0.50	2 paediatric
30 to 39.9	0.75	3 paediatric
40 and over	1.00	4 paediatric (this dose is better given as 1 adult tablet)

See the section on Children in Special risk groups for advice on how to administer antimalarials to children.

NaTHNaC has produced a useful summary table of children’s dosage.

Emergency standby treatment

Emergency standby treatment should be recommended for those taking chemoprophylaxis and visiting remote areas where they are unlikely to be within 24 hours of medical attention.

It is intended for those travellers who believe that they may have malaria and is not a replacement for chemoprophylaxis.

It is particularly important that the individual traveller is sufficiently well briefed to be able to use standby emergency treatment appropriately, as studies have shown that a significant proportion of travellers did not follow the pre-travel recommendations on administration of Emergency Standby Treatment, especially regarding the response to fever (82, 83). Therefore, written instructions for its use are required (84).

Standby emergency treatment should be started if it is impossible to consult a doctor and/or reach a diagnosis within 24 hours of the onset of fever.

Medical attention should be sought as soon as possible for full assessment and to exclude other serious causes of fever. This is particularly important as many illnesses other than malaria may present with fever.

The traveller should complete the standby treatment course and recommence their antimalarial chemoprophylaxis one week after taking the first treatment dose. If quinine is used for standby treatment, mefloquine prophylaxis should be resumed at least 12 hours after the last treatment dose. Antipyretics should be used to treat fever. A second full treatment dose of the antimalarial should be taken if vomiting occurs within 30 minutes of taking it (half-dose if vomiting occurs after 30 to 60 minutes) (85).

The agent used for emergency standby treatment should be different from the drugs used for chemoprophylaxis, both to minimise drug toxicity and due to concerns over drug resistance (86).

Individuals for whom emergency standby treatment is advised must be provided with written instructions for its use. In particular, they must be informed about symptoms suggesting possible malaria, including fever of 38°C and above, indications for starting the standby treatment, how to take it, expected side effects and the possibility of drug failure (86). The UK Malaria Expert Advisory Group (UKMEAG) recommended regimens for emergency standby treatment are given in Table 7 of Country recommendations.

Dihydroartemisinin-piperaquine has only recently been licensed in the EU and there are limited data on its use in travellers, so it cannot currently be recommended for this indication.

Sulfadoxine/pyrimethamine (SP) is not recommended due to reports of widespread resistance to this agent among P. falciparum strains. Halofantrine is no longer recommended due to concerns over its association with sometimes fatal cardiac arrhythmias (86).

Antimalarials purchased in the tropics may be fake (47) and travellers should obtain the medication required for their emergency standby treatment from a reputable source in the UK before they travel. UKMEAG also advises those purchasing antimalarial drugs over the internet to ensure that they are dealing with a bona fide supplier or website.

Table 7. Emergency standby treatment for adults

Situation for use	Standby treatment regimen	Usual amount per tablet	Adult dose
Chloroquine or multi-drug resistant falciparum malaria	Regimen 1: Artemether plus lumefantrine combination preparation	20mg artemether plus 120mg lumefantrine	4 tablets initially, followed by 5 further doses of 4 tablets each given at 8, 24, 36, 48 and 60 hours. Total 24 tablets over a period of 60 hours. Tablets should be taken with food to enhance drug absorption
Chloroquine or multi-drug resistant falciparum malaria	Regimen 2: Atovaquone plus proguanil combination preparation	250mg atovaquone plus 100mg proguanil	4 tablets as a single dose on each of 3 consecutive days
Chloroquine or multi-drug resistant alciparum malaria	Quinine plus doxycycline	300mg quinine 100mg doxycycline	Quinine 2 tablets 3 times a day for 3 days, accompanied by one tablet of doxycycline twice daily for 7 days
First, second or third trimester of pregnancy [note 6]	Regimen 1 (see above) is preferred. Regimen 3 is an alternative: Quinine plus clindamycin	300mg quinine 150mg clindamycin	Quinine 2 tablets 3 times a day for 5 to 7 days Clindamycin 3 tablets (450mg) 3 times a day for 5 days

Note 6: Pregnant travellers should avoid malarious areas. If that is not possible, artemether plus lumefantrine combination preparation can be used in all trimesters (World Health Organization (WHO) Guidelines for Malaria, 14 March 2023).

See Appendix 3 for an emergency standby medication traveller information leaflet which can be copied and pasted for use.

References

Numbers refer to the complete list of references found in the References section.

47. Dondorp A, Newton P, Mayxay M, Van Damme W, Smithuis F, Yeung S and others. ‘Fake antimalarials in Southeast Asia are a major impediment to malaria control: multinational cross‐sectional survey on the prevalence of fake antimalarials’ Tropical Medicine and International Health 2004: volume 9, issue 12, pages 1,241 to 1,246

48. Chulay JD. ‘Challenges in the development of antimalarial drugs with causal prophylactic activity’ Transactions of the Royal Society of Tropical Medicine and Hygiene 1998: volume 92, issue 6, pages 577 to 579

49. Franco-Paredes C, Santos-Preciado JI. ‘Problem pathogens: prevention of malaria in travellers’ The Lancet Infectious Diseases 2006: volume 6, issue 3, pages 139 to 149

50. Hill DR, Baird JK, Parise ME, Lewis LS, Ryan ET, Magill AJ. ‘Primaquine: report from CDC expert meeting on malaria chemoprophylaxis I’ The American Journal of Tropical Medicine and Hygiene 2006: volume 75, issue 3, pages 402 to 415

51. Hill D. ‘Issues for long-term and expatriate travellers.’ In: Cook GC, editor. ‘Travel- associated disease: papers based on a conference organised by the Royal College of Physicians of London’ Royal College of Physicians 1995: page 101

52. Pappaioanou M, Fishbein DB, Dreesen DW, Schwartz IK, Campbell GH, Sumner JW and others. ‘Antibody response to pre-exposure human diploid-cell rabies vaccine given concurrently with chloroquine’ New England Journal of Medicine 1986: volume 314, issue 5, pages 280 to 284

53. Schlagenhauf P, Adamcova M, Regep L, Schaerer MT, Rhein H-G. ‘The position of mefloquine as a 21st century malaria chemoprophylaxis’ Malaria Journal 2010: volume 9, issue 9, page 357

54. Moore DA, Grant AD, Armstrong M, Stümpfle R, Behrens RH. ‘Risk factors for malaria in UK travellers’ Transactions of the Royal Society of Tropical Medicine and Hygiene 2004: volume 98, issue 1, pages 55 to 63

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