Dermatological adverse effects with the antimalarial drug mefloquine: a review of 74 published case reports

The Intersection Between Malaria Treatment and Chemoprophylaxis and Their Potential Adverse Dermatologic Manifestations: A Narrative Review

Malaria is a life-threatening parasitic disease caused by various forms of the protozoa Plasmodium and is transmitted by the female Anopheles mosquito. The parasitic infection is endemic in 90 countries, with approximately 500 million cases reported annually and an estimated annual mortality of 1.5-2.7 million individuals. Historically, the use of antimalarial drugs has been promising for the chemoprophylaxis and treatment of malaria, mitigating the annual mortality rate. Notably, these antimalarial drugs have been associated with various adverse effects, including gastrointestinal upset and headaches. However, the adverse cutaneous manifestations these antimalarial drugs may lead to are poorly documented and understood. We aim to describe the lesser-studied adverse cutaneous pathologies of malaria treatment to better educate physicians on the proper treatment of their patients. Our narrative review describes the skin manifestations associated with specific antimalarial treatments and their associated prognoses and treatments. The cutaneous pathologies discussed include aquagenic pruritus (AP), palmoplantar exfoliation, Steven-Johnson syndrome, toxic epidermal necrolysis, cutaneous vasculitis, psoriasis, ecchymosis, and tropical lichenoid dermatitis. Further studies and vigilant documentation of the cutaneous adverse events of antimalarial drugs need to be performed and emphasized to prevent potential life-threatening adverse outcomes.

Pharmacokinetic Profile of Oral Administration of Mefloquine to Clinically Normal Cats: A Preliminary In-Vivo Study of a Potential Treatment for Feline Infectious Peritonitis (FIP)

Simple Summary

In searching for antiviral agents against feline coronaviruses and feline caliciviruses, mefloquine, a human anti-malarial drug, has been demonstrated to reduce viral load of feline coronaviruses and feline calicivirus in infected cells. In this study, mefloquine was administered orally to seven clinically healthy cats twice weekly for four doses and mefloquine concentrations in blood were measured to investigate the pharmacokinetic profile—the movement of drug in the body. The maximum blood concentration of mefloquine was 2.71 ug/mL and was reached 15 h after a single oral dose was administered. Mefloquine side effects included vomiting following administration without food in some cats, and mild increases in symmetric dimethylarginine (SDMA), an early kidney biomarker. This study provides valuable information on mefloquine’s profile in cats as an introductory step towards investigating it as a potential treatment for feline coronavirus and feline calicivirus infection in cats.

Abstract

The pharmacokinetic profile of mefloquine was investigated as a preliminary study towards a potential treatment for feline coronavirus infections (such as feline infectious peritonitis) or feline calicivirus infections. Mefloquine was administered at 62.5 mg orally to seven clinically healthy cats twice weekly for four doses and mefloquine plasma concentrations over 336 h were measured using high pressure liquid chromatography (HPLC). The peak plasma concentration (Cmax) after a single oral dose of mefloquine was 2.71 ug/mL and time to reach Cmax (Tmax) was 15 h. The elimination half-life was 224 h. The plasma concentration reached a higher level at 4.06 ug/mL when mefloquine was administered with food. Adverse effects of dosing included vomiting following administration without food in some cats. Mild increases in serum symmetric dimethylarginine (SDMA), but not creatinine, concentrations were observed. Mefloquine may provide a safe effective treatment for feline coronavirus and feline calicivirus infections in cats.

In vitro hepatic metabolism of mefloquine using microsomes from cats, dogs and the common brush-tailed possum (Trichosurus vulpecula)

Feline infectious peritonitis (FIP) is a systemic, fatal, viral-induced, immune-mediated disease of cats caused by feline infectious peritonitis virus (FIPV). Mefloquine, a human anti-malarial agent, has been shown to inhibit FIPV in vitro. As a first step to evaluate its efficacy and safety profile as a potential FIP treatment for cats, mefloquine underwent incubation in feline, canine and common brush-tailed possum microsomes and phase I metabolism cofactors to determine its rate of phase I depletion. Tramadol was used as a phase I positive control as it undergoes this reaction in both dogs and cats. Using the substrate depletion method, the in vitro intrinsic clearance (mean ± S.D.) of mefloquine by pooled feline and common brush-tailed possum microsomes was 4.5 ± 0.35 and 18.25 ± 3.18 μL/min/mg protein, respectively. However, phase I intrinsic clearance was too slow to determine with canine microsomes. Liquid chromatography-mass spectrometry (LC-MS) identified carboxymefloquine in samples generated by feline microsomes as well as negative controls, suggesting some mefloquine instability. Mefloquine also underwent incubation with feline, canine and common brush-tailed possum microsomes and phase II glucuronidative metabolism cofactors. O-desmethyltramadol (ODMT or M1) was used as a positive control as it undergoes a phase II glucuronidation reaction in these species. The rates of phase II mefloquine depletion by microsomes by all three species were too slow to estimate. Therefore mefloquine likely undergoes phase I hepatic metabolism catalysed by feline and common brush-tailed possum microsomes but not phase II glucuronidative metabolism in all three species and mefloquine is not likely to have delayed elimination in cats with clinically normal, hepatic function.

Mefloquine, an anti-malaria agent, causes reactive oxygen species-dependent cell death in mast cells via a secretory granule-mediated pathway

Mast cells are known to have a detrimental impact on a variety of pathological conditions. There is therefore an urgent need of developing strategies that limit their harmful effects. The aim of this study was to accomplish this by developing a means of inducing mast cell apoptosis. The strategy was to identify novel compounds that induce mast cell apoptosis by permeabilization of their secretory lysosomes (granules). As a candidate, we assessed mefloquine, an anti-malarial drug that has been proposed to have lysosome-permeabilizing activity. Mefloquine was added to mast cells and administered in vivo, followed by assessment of the extent and mechanisms of mast cell death. Mefloquine was cytotoxic to murine and human mast cells. Mefloquine induced apoptotic cell death of wild-type mast cells whereas cells lacking the granule compounds serglycin proteoglycan or tryptase were shown to undergo necrotic cell death, the latter finding indicating a role of the mast cell granules in mefloquine-induced cell death. In support of this, mefloquine was shown to cause compromised granule integrity and to induce leakage of granule components into the cytosol. Mefloquine-induced cell death was refractory to caspase inhibitors but was completely abrogated by reactive oxygen species inhibition. These findings identify mefloquine as a novel anti-mast cell agent, which induces mast cell death through a granule-mediated pathway. Mefloquine may thus become useful in therapy aiming at limiting harmful effects of mast cells.

Inhibition of allogeneic inflammatory responses by the Ribonucleotide Reductase Inhibitors, Didox and Trimidox

Background

Graft-versus-host disease is the single most important obstacle facing successful allogeneic stem cell transplantation (SCT). Even with current immunosuppressive therapies, morbidity and mortality rates are high. Current therapies including cyclosporine A (CyA) and related compounds target IL-2 signaling. However, although these compounds offer great benefit, they are also associated with multiple toxicities. Therefore, new compounds with a greater efficacy and reduced toxicity are needed to enable us to overcome this hurdle.

Methods

The allogeneic mixed lymphocyte reaction (MLR) is a unique ex vivo method to study a drug's action on the initial events resulting in T-cell activation and proliferation, synonymous to the initial stages of tissue and organ destruction by T-cell responses in organ rejection and Graft-versus-host disease. Using this approach, we examined the effectiveness of two ribonucleotide reductase inhibitors (RRI), Didox and Trimidox, to inhibit T-cell activation and proliferation.

Results

The compounds caused a marked reduction in the proliferative responses of T-cells, which is also accompanied by decreased secretion of cytokines IL-6, IFN-γ, TNF-α, IL-2, IL-13, IL-10 and IL-4.

Conclusions

In conclusion, these data provide critical information to justify further investigation into the potential use of these compounds post allogeneic bone marrow transplantation to alleviate graft-versus-host disease thereby achieving better outcomes.

Mefloquine adverse effects with atypical facial lesions in an overweight patient

BACKGROUND

The recommended dosage of mefloquine to treat Plasmodium falciparum infection is 25 mg/kg, with no recommendation for dosage exceeding 1500 mg. We describe an original case of adverse reaction to mefloquine in an overweight patient.

METHOD

Case report.

RESULTS

A 32-year-old woman weighing 139 kg presented with uncomplicated P. falciparum infection after returning from Cameroon. She received 3250 mg of mefloquine (i.e. 23 mg/kg) administered in four doses. On day 2, she developed neuropsychiatric disorders and facial lesions. Nasal mucocutaneous vesicles and bullae, depressive mood, mild thrombocytopenia and hepatic cytolysis were evidenced. Parasitemia was negative. Recovery was complete on day 17. High mefloquine serum levels were measured (8.030 mg/L on day 3, 6.880 mg/L on day 8, and 3.370 mg/L on day 17).

CONCLUSIONS

The causal relationship between mefloquine and the occurrence of these adverse effects is probable. However, as no viral or bacteriological investigations were performed, the drug responsibility remains uncertain. Mefloquine-induced bullous and facial lesions reversible upon drug withdrawal have already been described. The associated neuropsychiatric symptoms were strongly suggestive of mefloquine adverse effects, as such events are more frequently observed in cases of overdosage. Our case emphasizes the difficulties of dosage adaptation in overweight patients.

Drugs for preventing malaria in travellers

BACKGROUND

Malaria infects 10,000 to 30,000 international travellers each year. It can be prevented through anti-mosquito measures and drug prophylaxis. However, antimalaria drugs have adverse effects which are sometimes serious.

OBJECTIVES

To compare the effects of currently used antimalaria drugs when given as prophylaxis to non-immune adult and child travellers who are travelling to regions with Plasmodium falciparum resistance to chloroquine. Specifically, to assess the efficacy, safety, and tolerability of atovaquone-proguanil, doxycycline, and mefloquine compared to each other, and also when compared to chloroquine-proguanil and to primaquine.

SEARCH STRATEGY

In August 2009 we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2008, Issue 4), MEDLINE, EMBASE, LILACS, BIOSIS, mRCT, and reference lists. We handsearched conference proceedings and one specialist journal, and contacted researchers and drug companies. We searched PubMed for drug-related deaths.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of any antimalaria drug regimen currently used by non-immune international travellers.

DATA COLLECTION AND ANALYSIS

We independently extracted data and assessed eligibility and risk of bias using a standardized data collection form. We resolved any disagreement through discussion. We combined dichotomous outcomes using risk ratio (RR) and continuous data using mean difference (MD), presenting both with 95% confidence intervals (CI).

MAIN RESULTS

Eight trials (4240 participants) met the inclusion criteria. Evidence on comparative efficacy from head-to-head comparisons was limited. Atovaquone-proguanil compared to doxycycline had similar adverse events reported. Compared to mefloquine, atovaquone-proguanil users had fewer reports of any adverse effect (RR 0.72, 95% CI 0.6 to 0.85), gastrointestinal adverse effects (RR 0.54, 95% CI 0.42 to 0.7), neuropsychiatric adverse events (RR 0.86, 95% CI 0.75 to 0.99), and neuropsychiatric adverse effects (RR 0.49, 95% CI 0.38 to 0.63), besides a better total mood disturbance score (MD -7.20, 95% CI -10.79 to -3.61). Similarly, doxycycline users had fewer reported neuropsychiatric events than mefloquine users (RR 0.84, 95% CI 0.73 to 0.96). We also examined these three regimens against chloroquine-proguanil; this latter regimen had more reports of any adverse effect (RR 0.84, 95% CI 0.73 to 0.96) and of gastrointestinal adverse effects (RR 0.71, 95% CI 0.6 to 0.85).

AUTHORS' CONCLUSIONS

Atovaquone-proguanil and doxycycline are the best tolerated regimens, and mefloquine is associated with adverse neuropsychiatric outcomes.

Toxic epidermal necrolysis (TEN) Lyell's syndrome

Toxic epidermal necrolysis, a unique rapidly developing mucocutaneous reaction pattern, characterized by sheets of erythema, necrosis and bullous detachment of the epidermis, closely resembling that of scalding of the skin and rapidly fatal, was described by Lyell, and is now recognized as toxic epidermal necrolysis (TEN) Lyell's syndrome. The condition is indistinguishable from staphylococcal scalded skin syndrome (SSSS), and generalized fixed drug eruption. Hence, there has always been controversy as regards terminology. It is well conceived that TEN is equivalent to Stevens-Johnson syndrome (SJS), at its greatest severity. TEN, therefore, is a great challenge and warrants instant attention based on a thorough knowledgeable background covering several related facets including the recent advances in pathogenesis and management strategies. The details contained in the following text should prove very useful in the comprehension of a largely intractable entity.

WITHDRAWN: Mefloquine for preventing malaria in non-immune adult travellers

BACKGROUND

Mefloquine is commonly prescribed to prevent malaria in travellers, and has replaced other drugs because Plasmodium falciparum is commonly resistant to them. However, mefloquine may be associated with neuropsychiatric harmful effects.

OBJECTIVES

To assess the effects of mefloquine in adult travellers compared to other regimens in relation to episodes of malaria, withdrawal from prophylaxis, and adverse events.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group specialized trials register (September 2002), The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2002), MEDLINE (1966 to September 2002), EMBASE (1980 to September 2002), LILACS (September 2002), Science Citation Index (1981 to September 2002), and bibliographies in retrieved papers and standard textbooks. We contacted researchers in the subject of malaria chemoprophylaxis, and pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing mefloquine with other standard prophylaxis or placebo in non-immune adult travellers, and in non-travelling volunteers. For adverse events, any published case reports were collected.

DATA COLLECTION AND ANALYSIS

We independently assessed trial quality and extracted data. Adverse events from observational studies were categorised by the study type. We also contacted study authors.

MAIN RESULTS

We included 10 trials involving 2750 non-immune adult participants. Five of these were field trials, and of these all were in mainly male soldiers. One trial comparing mefloquine with placebo showed mefloquine prevented malaria episodes in an area of drug resistance (Peto odds ratio 0.04, 95% confidence interval 0.02 to 0.08). Withdrawals in the mefloquine group were consistently higher in four placebo controlled trials (odds ratio 3.56, 95% confidence interval 1.67 to 7.60). In five trials comparing mefloquine with other chemoprophylaxis, no difference in tolerability was detected. We found 516 published case reports of mefloquine adverse effects. 63 per cent of these published reports involved tourists and business travellers. There were four fatalities attributed to mefloquine.

AUTHORS' CONCLUSIONS

Mefloquine prevents malaria, but has adverse effects that limit its acceptability . There is evidence from non-randomised studies that mefloquine has potentially harmful effects in tourists and business travellers, and its use needs to be carefully balanced against this. Trials of comparative effects of antimalarial prophylaxis should include episodes of malaria and withdrawal from prophylaxis as outcomes.

Methotrexate versus hydroxycarbamide (hydroxyurea) as a weekly dose to treat moderate-to-severe chronic plaque psoriasis: a comparative study

BACKGROUND

Literature is replete with reports on the therapeutic efficacy and toxicity of methotrexate or hydroxycarbamide for treating chronic plaque psoriasis but no comparative study on their efficacy/safety has been carried out. While methotrexate has long been used in weekly doses in the treatment of psoriasis, the efficacy of hydroxycarbamide as a weekly therapy remains universally unexplored.

METHODS

Two groups of 15 patients each having moderate-to-severe chronic plaque psoriasis were given weekly doses of methotrexate (15-20 mg/week) or hydroxycarbamide (3-4.5 g/week). The clinical response was assessed by the percentage reduction in the baseline PASI scores for the next 12 weeks.

RESULTS

At the end of 12 weeks, the mean percentage reduction in the PASI score was 77.28+/-18.80 in the methotrexate group and 48.47+/-26.53 in the hydroxycarbamide group. Ten (66.66%) patients in the methotrexate group achieved >75% reduction in the PASI score, while in the hydroxycarbamide group only two (13.33%) patients showed similar results, signifying that methotrexate leads to a faster clearance of the disease. The methotrexate-related side effects, however, were also higher.

CONCLUSIONS

Weekly doses of hydroxycarbamide can be used as an alternative to methotrexate in patients who either experience intolerable methotrexate side effects or have achieved its recommended cumulative dose.

JJ, Bosch RJ, Rosenkranz SL, Cramer YS, Ussery M, Flexner C. Effect of hydroxyurea and dideoxyinosine on intracellular 3'-deoxyadenosine-5'-triphosphate concentrations in HIV-infected patients

Hydroxyurea (HU) significantly enhances the antiretroviral effects of the adenosine analog reverse transcriptase inhibitor dideoxyinosine (ddI). This is believed to be due to a reduction in intracellular de-oxyadenosine triphosphate (dATP) concentrations resulting from HU-mediated inhibition of ribonucleotide reductase (RnR). The effect of combined HU-ddI treatment on intracellular dATP pools in vivo has not been examined. We measured intracellular dATP concentrations in peripheral blood mononuclear cells (PBMCs) from 69 HIV-infected patients receiving 1000 or 1500 mg HU daily for 14 days, 200 mg ddI twice daily for 14 days, or a combination of the two drugs. Median intracellular dATP concentrations decreased from base-line to day 14 by 46% in the ddI + 1000 mg HU arm and by 62% in the ddI + 1500 mg HU arm. When compared to the HU monotherapy arms, these changes proved statistically significant (p = 0.018; stratified Wilcoxon rank-sum test). These findings support reduced intracellular dATP as the mechanism of ddI-HU synergistic activity, and indicate that changes in intracellular nucleotides contribute to HU activity and toxicity in patients. Since a significant reduction in dATP was measurable only when ddI was combined with HU, the antiretroviral activity of ddI may be more complex than previously assumed.

Adverse cutaneous reactions to antimicrobials in patients with human immunodeficiency virus infection

Adverse reactions to medication are significant contributors to morbidity and mortality in patients with human immunodeficiency virus (HIV) infection. Cutaneous events not only constitute a significant portion of these reactions, they may also herald developing systemic reactions such as hemato-, nephro-, and hepatotoxicity. The identification of cutaneous adverse reactions and drug culprits and the proper management of reactions are of paramount importance for these patients. This review focuses specifically on adverse cutaneous reactions to antimicrobials that are commonly used in the management of patients with HIV infection.

The effect of various methods of psoriasis treatment on somatotrophin axis hormones in serum

OBJECTIVE

To investigate the effect of pharmacotherapy and phototherapy on the concentration of hormones of the somatotrophin axis [growth hormone (GH), insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3)] in the serum of patients with psoriasis in exacerbation and remission.

METHODS

GH and IGFBP-3 in serum were determined by immunoradiometric assay (IRMA), and IGF-I concentrations - by radioimmunological assay (RIA). The dermatological state was assessed by the psoriasis area and severity index (PASI).

RESULTS

There was no significant difference in the GH concentrations in patients both in exacerbation and remission, irrespective of therapy applied. However, in the group treated by phototherapy a significant increase in IGFBP-3 secretion was observed, whereas in the group treated with cyclosporin A - a significant increase in IGF-I secretion was observed in remission.

CONCLUSION

Different methods of treatment have different effects on the secretion of somatotrophin axis hormones, but generally the hormone concentrations do not return to the values observed in healthy people. The therapeutic actions of the drugs concerned are not fully known and require further investigations.

Optimal management of severe plaque form of psoriasis

Psoriasis is a chronic, inflammatory, hyperproliferative skin disease that affects 1-2% of the general population in the UK and US. Plaque psoriasis is the most common form, accounting for approximately 90% of cases. The disease is usually chronic and persistent, although up to 50% of patients may enter spontaneous remission for varying periods of time. There is no cure for psoriasis; therefore, the aim of treatment is to minimize the extent and severity of the disease to the point at which it no longer substantially disrupts the patient's quality of life. First-line therapy of psoriasis usually consists of topical agents, such as emollients, tar, dithranol, and vitamin D3 analogs. In cases of severe, extensive psoriasis, where topical therapy is either impractical or not sufficiently effective, systemic treatment may be warranted at the outset. In these circumstances, the therapeutic options include: (i) intensive inpatient or day center topical therapy; (ii) phototherapy; and/or (iii) systemic agents. There are now a number of systemic agents available for the treatment of severe psoriasis, but all have potential adverse effects. We review the current treatment options, which include the use of phototherapy and systemic agents, and provide recommendations on their use in clinical practice. Importantly, treatment should be tailored to each individual patient depending on concurrent medical problems (which might preclude certain agents), patient choice and acceptance of the risk of adverse effects.

Mefloquine toxicity presenting with polyneuropathy - a report of two cases in India

We report two cases of people from different states in India who developed polyneuropathy following intake of mefloquine for treatment of malaria. To the best of our knowledge this has not been reported before.

Antimalarial Drug Toxicity

Malaria, caused mostly by Plasmodium falciparum and P. vivax, remains one of the most important infectious diseases in the world. Antimalarial drug toxicity is one side of the risk-benefit equation and is viewed differently depending upon whether the clinical indication for drug administration is malaria treatment or prophylaxis. Drug toxicity must be acceptable to patients and cause less harm than the disease itself. Research that leads to drug registration tends to omit two important groups who are particularly vulnerable to malaria--very young children and pregnant women. Prescribing in pregnancy is a particular problem for clinicians because the risk-benefit ratio is often very unclear. The number of antimalarial drugs in use is very small. Despite its decreasing efficacy against P. falciparum, chloroquine continues to be used widely because of its low cost and good tolerability. It remains the drug of first choice for treating P. vivax malaria. Pruritus is a common adverse effect in African patients. As prophylaxis, chloroquine is usually combined with proguanil. This combination has good overall tolerability but mouth ulcers and gastrointestinal upset are more common than with other prophylactic regimens. Sulfadoxine/pyrimethamine is well tolerated as treatment and when used as intermittent preventive treatment in pregnant African women. Sulfadoxine/pyrimethamine is no longer used as prophylaxis because it may cause toxic epidermal necrolysis and Stevens Johnson syndrome. Mefloquine remains a valuable drug for prophylaxis and treatment. Tolerability is acceptable to most patients and travellers despite the impression given by the lay press. Dose-related serious neuropsychiatric toxicity can occur; mefloquine is contraindicated in individuals with a history of epilepsy or psychiatric disease. Quinine is the mainstay for treating severe malaria in many countries. Cardiovascular or CNS toxicity is rare, but hypoglycaemia may be problematic and blood glucose levels should be monitored. Halofantrine is unsuitable for widespread use because of its potential for cardiotoxicity. There is renewed interest in two old drugs, primaquine and amodiaquine. Primaquine is being developed as prophylaxis, and amodiaquine, which was withdrawn from prophylactic use because of neutropenia and hepatitis, is a potentially good partner drug for artesunate against falciparum malaria. Atovaquone/proguanil is a new antimalarial combination with good efficacy and tolerability as prophylaxis and treatment. The most important class of drugs that could have a major impact on malaria control is the artemisinin derivatives. They have remarkable efficacy and an excellent safety record. They have no identifiable dose-related adverse effects in humans and only very rarely produce allergic reactions. Combining an artemisinin derivative with another efficacious antimalarial drug is increasingly being viewed as the optimal therapeutic strategy for malaria.

Adverse effects of the antimalaria drug, mefloquine: due to primary liver damage with secondary thyroid involvement?

BACKGROUND

Mefloquine is a clinically important antimalaria drug, which is often not well tolerated. We critically reviewed 516 published case reports of mefloquine adverse effects, to clarify the phenomenology of the harms associated with mefloquine, and to make recommendations for safer prescribing.

PRESENTATION

We postulate that many of the adverse effects of mefloquine are a post-hepatic syndrome caused by primary liver damage. In some users we believe that symptomatic thyroid disturbance occurs, either independently or as a secondary consequence of the hepatocellular injury. The mefloquine syndrome presents in a variety of ways including headache, gastrointestinal disturbances, nervousness, fatigue, disorders of sleep, mood, memory and concentration, and occasionally frank psychosis. Previous liver or thyroid disease, and concurrent insults to the liver (such as from alcohol, dehydration, an oral contraceptive pill, recreational drugs, and other liver-damaging drugs) may be related to the development of severe or prolonged adverse reactions to mefloquine.

IMPLICATIONS

We believe that people with active liver or thyroid disease should not take mefloquine, whereas those with fully resolved neuropsychiatric illness may do so safely. Mefloquine users should avoid alcohol, recreational drugs, hormonal contraception and co-medications known to cause liver damage or thyroid damage. With these caveats, we believe that mefloquine may be safely prescribed in pregnancy, and also to occupational groups who carry out safety-critical tasks.

TESTING

Mefloquine's adverse effects need to be investigated through a multicentre cohort study, with small controlled studies testing specific elements of the hypothesis.

Drug-induced urticaria. Recognition and treatment

Urticaria is the second most common cutaneous manifestation of drug allergy. Drug-induced urticaria is seen in 0.16% of medical inpatients and accounts for 9% of chronic urticaria or angioedema seen in dermatology outpatient departments. Occurring within 24 hours of drug ingestion, it is most commonly caused by penicillins, sulfonamides and nonsteroidal anti-inflammatory drugs. Drug-induced urticaria is seen in association with anaphylaxis, angioedema, and serum sickness. Diagnosis requires a detailed history, knowledge of the most likely agents sometimes supplemented with in vitro and skin testing. For mild reactions, avoidance of the causative drug and treatment with antihistamines will suffice. For anaphylactic shock, treatment with epinephrine (adrenaline), corticosteroids and antihistamines is required. Patients should be educated to inform medical staff about previous drug reactions, and to avoid these and cross-reacting drugs if possible. Medical staff need to routinely enquire about allergy and avoid unnecessary prescriptions.

Cutaneous and systemic manifestations of drug-induced vasculitis

OBJECTIVE

To evaluate the literature for published cases of drug-induced vasculitis with cutaneous and/or systemic manifestations.

DATA SOURCES

The MEDLINE database was searched from 1965 to December 1999 for articles focusing on drugs and vasculitis, using various search terminologies (e.g., Churg-Strauss syndrome, Goodpasture's syndrome, Henoch-Schönlein purpura, various drugs suspected to induce vasculitis). Cases were included when they met the established criteria as described in the methodology.

DATA SYNTHESIS

Drugs found to be most frequently associated with vasculitis were propylthiouracil, hydralazine, colony-stimulating factors, allopurinol, cefaclor, minocycline, D-penicillamine, phenytoin, isotretinoin, and methotrexate. The interval between the first exposure and appearance of symptoms was reported to be extremely variable (hours to years). Vasculitis has occurred after drug dosage increases and after rechallenge with the suspected drug. In the majority of cases, vasculitis has resolved after discontinuing the drug. Patients with more severe, often life-threatening, manifestations have required treatment with corticosteroids, plasmapheresis, hemodialysis, or cyclophosphamide. Death was the result in 10% of all published cases, with a predominance in patients in whom multiple organ systems were involved.

CONCLUSIONS

Clinicians need to be suspect of drug-induced vasculitis to enable prompt diagnosis and treatment. This should improve patient outcomes based on the data referenced for this article.

Drug-induced vasculitis

DIV is a relatively common cause of inflammatory vasculitis. Drugs from almost every pharmacologic class have been implicated in causing vasculitis in sporadic cases. The level of certainty and quality of evidence for these associations between specific agents and vasculitis vary greatly. The clinical manifestations of DIV range from single organ involvement (most commonly, skin) to life-threatening multiorgan disease. The recently described subset of cases of DIV associated with positive tests for ANCA are an interesting subset of DIV. The diagnosis of DIV is usually one of exclusion. The treatment of DIV is dependent on the severity of disease activity but should always include withdrawal of the suspected drug. If no agent can be implicated, as many drugs as feasible should be discontinued. The necessity of prescribing glucocorticoids or immunosuppressive agents depends on the disease severity and other case-specific information. Increasing understanding of the pathophysiologic characteristics of all inflammatory vasculitides should lead to better diagnostic and therapeutic approaches to DIV.

Rediscovering hydroxyurea: its role in recalcitrant psoriasis

BACKGROUND

There is an acute paucity of second-line systemic agents for the treatment of extensive chronic plaque psoriasis (CPP). Recent studies using hydroxyurea in patients with HIV infection and sickle cell anemia have rekindled interest in this old drug and have provided more data regarding safety and dosage.

OBJECTIVE

We wanted to test the efficacy and tolerability of hydroxyurea in patients with extensive CPP who had to discontinue first-line oral agents for any reason.

METHODS

The study was a prospective nonrandomized series. Thirty-one patients, including 26 with prior history of systemic antipsoriatic therapy were given hydroxyurea 1-1.5 g per day for a median duration of 36 weeks. They were followed up for a mean period of 36.1 +/- 13.8 weeks.

RESULTS

Almost 75% of the patients showed an adequate response (35% reduction in Psoriasis Area and Severity Index at or before 8 weeks) with over half showing more than 70% reduction in PASI score. All adverse effects were mild and reversible and none of the patients required cessation of therapy.

CONCLUSION

Hydroxyurea is an effective, very safe but relatively slower acting alternative for patients with extensive CPP over the short-to-medium term.

Extracts from "Clinical Evidence". Malaria: prevention in travellers

DEFINITION

Malaria is caused by a protozoan infection of red blood cells with one of four species of the genus plasmodium: P falciparum, P vivax, P ovale, or P malariae. Clinically, malaria may present in different ways, but it is usually characterised by fever (which may be swinging), tachycardia, rigors, and sweating. Anaemia, hepatosplenomegaly, cerebral involvement, renal failure, and shock may occur. INCIDENCE/PREVALENCE: Each year there are 300-500 million clinical cases of malaria. About 40% of the world's population is at risk of acquiring the disease. Each year 25-30 million people from non-tropical countries visit areas in which malaria is endemic, of whom between 10,000 and 30,000 contract malaria. AETIOLOGY/RISK FACTORS: Malaria is mainly a rural disease, requiring standing water nearby. It is transmitted by bites from infected female anopheline mosquitoes, mainly at dusk and during the night. In cities, mosquito bites are usually from female culicene mosquitoes, which are not vectors of malaria. Malaria is resurgent in most tropical countries and the risk to travellers is increasing.

PROGNOSIS

Ninety per cent of travellers who contract malaria do not become ill until after they return home. "Imported malaria" is easily treated if diagnosed promptly, and it follows a serious course in only about 12% of people. The most severe form of the disease is cerebral malaria, with a case fatality rate in adult travellers of 2-6%, mainly because of delays in diagnosis.

AIMS

To reduce the risk of infection; to prevent illness and death.

OUTCOMES

Rates of malarial illness and death, and adverse effects of treatment. Proxy measures include number of mosquito bites and number of mosquitoes in indoor areas. We found limited evidence linking number of mosquito bites and risk of malaria.

METHODS

Clinical Evidence search and appraisal in November 1999. We reviewed all identified systematic reviews and randomised controlled trials (RCTs).

Chemotherapy for falciparum malaria: the armoury, the problems and the prospects

Peter Winstanley here describes the pharmacology and therapeutics of the main drugs used for falciparum malaria in the tropical setting, rather than in the developed world, as an overview for newcomers to the field. He then examines some of the current major problems and prospects for the future.

Mefloquine for preventing malaria in non-immune adult travellers

OBJECTIVES

Mefloquine has now largely replaced earlier malaria prophylaxis drugs which are no longer considered to be effective against all Plasmodium species, due to parasite resistance. However mefloquine may be associated with neuropsychological harmful effects. The objective of this review was to assess the effects of mefloquine in adult travellers.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register, Medline, Embase, Lilacs, Science Citation Index and reference lists of articles. We contacted researchers in the subject of malaria chemoprophylaxis, and drug companies.

SELECTION CRITERIA

Randomised trials comparing mefloquine with other standard prophylaxis or placebo in non-immune adult travellers.

DATA COLLECTION AND ANALYSIS

The two reviewers independently assessed trial quality and extracted data. Study authors were also contacted.

MAIN RESULTS

Ten trials involving 2750 non-immune adult travellers were included. One trial comparing mefloquine with placebo showed mefloquine prevented malaria episodes in an area of drug resistance (odds ratio 0.04, 95% confidence interval 0.02 to 0.08). Withdrawals in the mefloquine group were consistently higher in four placebo controlled trials (odds ratio 3. 56, 95% confidence interval 1.67 to 7.60). In five trials comparing mefloquine with other chemoprophylaxis, no difference in tolerability was detected.

REVIEWER'S CONCLUSIONS

Mefloquine prevents malaria, but there is not enough evidence to evaluate its tolerability and toxicity, particularly for general travellers.