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Chloroquine phosphate oral solid dosage


Tablets containing chloroquine phosphate (250 mg of chloroquine phosphate is equivalent to 155 mg chloroquine base).

Drugs List

  • AVLOCLOR 250mg tablets
  • chloroquine phosphate 250mg tablets
  • Therapeutic Indications


    Amoebic hepatitis
    Lupus erythematosus
    Malaria - prophylaxis
    Malaria - treatment
    Rheumatoid arthritis

    Treatment of malaria

    Prophylaxis and suppression of malaria

    Treatment of amoebic hepatitis and abscess

    Treatment of discoid and systemic lupus erythematosus

    Treatment of rheumatoid arthritis

    For up to date advice on geographical resistance patterns and appropriate prophylaxis, current guidelines should be consulted.
    Guidelines for Malaria Prevention from Public Health England specifically developed for travellers from the United Kingdom may be obtained from:


    Chloroquine is no longer recommended for the treatment of falciparum malaria due to widespread resistance, nor is it recommended if the infective species is unknown of if the infection is mixed.

    If further attention is required to destroy parasites in the liver, to prevent relapse when treating P. vivax and P. ovale infections, follow with a course of primaquine.


    Treatment of malaria (P. falciparum, P. malariae, P. vivax and P. ovale infections)
    620mg (four tablets) taken as a single dose, followed by 310mg (two tablets) six hours later, and then 310mg (two tablets) daily for the following two days.

    Prophylaxis and suppression of malaria
    310mg (two tablets) once a week, taken on the same day of the week.
    Commence treatment one week prior to exposure to risk and continue for four weeks after leaving the malarious area.

    Treatment of amoebic hepatitis
    620mg (four tablets) daily for two days, followed by 155mg (one tablet) twice daily for the following two or three weeks.

    Treatment of lupus erythematosus
    155mg (one tablet) twice daily for one or two weeks, followed by a maintenance dose of one tablet per day.

    Treatment of rheumatoid arthritis
    155mg (one tablet) daily.


    Treatment of malaria (P. falciparum, P. malariae, P. vivax and P. ovale infections)
    10mg chloroquine base/kg as a single dose, followed by 5mg chloroquine base/kg six hours later, then 5mg chloroquine base/kg daily for two days.

    Children aged 9 to 14 years:
    Three tablets as a single dose, followed by one and a half tablets six hours later and then one and a half tablets daily for a further two days.
    Children aged 5 to 9 years:
    Two tablets as a single dose, followed by one tablet six hours later and then one tablet daily for a further two days.
    Children aged 1 to 5 years:
    One tablet as a single dose, followed by half a tablet six hours later and then half a tablet daily for a further two days.

    The following alternative dosing schedule may be suitable for the treatment of malaria caused by P. vivax, P. ovale or P. malariae
    10mg/kg (maximum 620mg) of chloroquine base as a single dose, followed by 5mg/kg (maximum 310mg) of chloroquine base 6 to 8 hours later and then 5mg/kg (maximum 310mg) of chloroquine base once daily for two days.

    Prophylaxis and suppression of malaria
    5mg chloroquine base/kg once per week on the same day each week.
    Commence treatment one week prior to exposure to risk and continue for four weeks after leaving the malarious area. The dose must not exceed the adult dosage regardless of body weight.
    Children aged 9 to 15 years: One and a half tablets.
    Children aged 5 to 9 years: One tablet.
    Children aged 1 to 5 years: Half a tablet.

    The following alternative dosing schedule may be suitable for the prophylaxis of malaria, started one week before entering endemic area and continuing for four weeks after leaving:
    Children aged over 13 years (bodyweight over 45kg): 310mg chloroquine base once weekly.
    Children aged 8 to 13 years (bodyweight 25kg to 45kg): 232.5mg chloroquine base once weekly.
    Children aged 4 to 8 years (bodyweight 16.5kg to 25kg): 155mg chloroquine base once weekly.
    Children aged 3 to 4 years (bodyweight 15kg to 16.5kg): 125mg chloroquine base once weekly.
    Children aged 1 to 3 years (bodyweight 11kg to 15kg): 100mg chloroquine base once weekly.
    Children aged 6 months to 1 year (bodyweight 8kg to 11kg): 75mg chloroquine base once weekly.
    Children aged 6 weeks to 6 months (bodyweight 4.5kg to 8kg): 50mg chloroquine base once weekly.
    Children aged up to 6 weeks (bodyweight under 4.5kg): 25mg chloroquine base once weekly.
    The oral liquid preparation may more be suitable for young children. The separate monograph for the oral liquid preparation should be consulted for further information.

    Patients with Renal Impairment

    The Renal Drug Handbook makes the following dose suggestions:
    Glomerular filtration rate (GFR) between 10 and 50ml/minute: Dose as in normal renal function
    Glomerular filtration rate (GFR) less than 10ml/minute: Half the normal dose


    Long QT syndrome
    Torsade de pointes

    Precautions and Warnings

    Children under 1 year
    Family history of long QT syndrome
    Diabetes mellitus
    Electrolyte imbalance
    Epileptic disorder
    G6PD deficiency
    Hepatic cirrhosis
    Hepatic impairment
    History of seizures
    History of torsade de pointes
    Myasthenia gravis
    Renal impairment

    Correct electrolyte disorders before treatment
    Monitor for haemolysis in G6PD deficiency
    Reduce dose in patients with a glomerular filtration rate below 10ml/min
    Advice available from specialist unit for the use of this drug
    Advise visual disturbances may affect ability to drive or operate machinery
    Consider prevalence of resistance when prescribing
    Drugs for malaria prophylaxis are not prescribable on the NHS
    Perform ECG before and during treatment
    Perform ophthalmological examination before therapy and 3-6 monthly
    Monitor cardiac function during prolonged treatment
    Monitor serum electrolytes
    Monitor the elderly for optimum dosing
    Perform blood counts on prolonged use of this treatment
    Advise patient to report any symptoms of interstitial lung disease
    Advise patient to report new visual problems and symptoms
    May exacerbate psoriasis
    May induce severe hypoglycaemia
    Predisposition QT prolongation: Counsel patient on symptoms of arrhythmias
    Advise of importance of avoiding mosquito bites
    Advise patients of the warning signs of hypoglycaemia
    Advise patients on the importance of taking treatment regularly
    Consult Dr. if illness occurs within 1 year of return from malarious area

    Although chloroquine may have a temporary effect on visual accommodation during short term treatment, irreversible retinal damage may occur with prolonged treatment and after treatment has been discontinued. Ophthalmological examinations should always be carried out before and regularly during prolonged treatment. Retinal damage is particularly likely to occur if:
    - Continuous high doses have been given for longer than one year.
    - The total dosage has exceeded 1.6 g/kg bodyweight (cumulative dose approximately 100 g).
    - Patients receive chloroquine continuously at weekly intervals for more than three years.

    Chloroquine may precipitate severe constitutional symptoms and an increase in the amount of porphyrins excreted in the urine.
    Patients with a high alcohol intake are particularly at risk. The drug database for acute porphyria (NAPOS) class this drug as being possibly porphyrinogenic. It suggests chloroquine should only be used when no safer alternative is available.

    Pregnancy and Lactation


    Use chloroquine with caution during pregnancy.

    The manufacturer does not recommend using chloroquine during pregnancy. Available reports indicate that when used in high doses or on a long term basis, chloroquine therapy has been linked to foetal abnormalities such as vision loss, ototoxicity and cochlear-vestibular dysfunction.

    Non-treatment of malaria can produce severe complications for mother and foetus including: maternal death, anaemia, abortion, stillbirth, prematurity, low birth weight, foetal distress. The choice of drug for malaria prophylaxis and treatment during pregnancy depends upon the local pattern of drug resistance, severity of malaria and the degree of pre-existing malaria immunity.


    Use chloroquine with caution during breastfeeding.

    The manufacturer advises caution if chloroquine is used during breastfeeding. Breastfeeding is not recommended in patients taking chloroquine long-term or at high doses e.g. for rheumatoid disease or lupus erythematosus. Available data indicates that chloroquine is expressed in human breast milk but at levels too low to harm the infant. The levels excreted are insufficient to provide the infant with protection against malaria. If appropriate, chemoprophylaxis should be administered to the infant.


    For oral administration to be taken after food.

    When chloroquine sulfate is used for malaria prophylaxis warn travellers about the importance of avoiding mosquito bites, the importance of taking prophylaxis regularly, and the importance of an immediate visit to a doctor if they fall ill within 1 year and especially within 3 months of return.

    Antacids may impair absorption, therefore antacids should be taken at least 2 hours before or 2 hours after administration with chloroquine.

    Patients should be advised to discontinue the medication and seek immediate medical advice if they notice any deterioration in their vision which persists for more than 48 hours.

    Advise patients to report symptoms of interstitial lung disease.

    Ability to drive and operate machinery may be affected by side effects, in particular visual disturbances.

    Side Effects

    Abdominal pain
    Abnormal liver function tests
    Acute generalised exanthematous pustulosis
    Aggravation of porphyria
    Anaphylactic reaction
    Aplastic anaemia
    Blurred vision
    Bone marrow depression
    Corneal opacities
    Disturbances in accommodation
    Drug rash with eosinophilia and systemic symptoms (DRESS)
    ECG changes
    Erythema multiforme
    Exacerbation of myasthenia gravis
    Exacerbation of psoriasis
    Exfoliative dermatitis
    Gastro-intestinal disturbances
    Hair loss
    Hepatic damage
    Hypersensitivity reactions
    Interstitial lung disease
    Lichen-planus type reaction
    Liver function disturbances
    Macular degeneration of colour vision
    Maculopapular rash
    Nerve deafness
    Optic atrophy scotomas
    Personality change
    Pigmentation of mucous membranes
    Pigmentation of nails
    Pigmented deposits in the eye
    Prolongation of QT interval
    Psychotic reactions
    Retinal damage (irreversible)
    Skin pigmentation changes
    Stevens-Johnson syndrome
    Toxic epidermal necrolysis
    Vasculitis (allergic)
    Visual field defects


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: April 2020

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Summary of Product Characteristics: Avloclor tablets. Alliance Pharmaceuticals Limited. Revised October 2016.

    The Renal Drug Handbook. Fifth Edition (2019) ed. Ashley, C. and Dunleavy, A. Radcliffe Publishing Ltd, London.

    NICE - Evidence Services
    Available at:
    Last accessed: 08 April 2020

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Chloroquine Last revised: 31 October 2018
    Last accessed: 08 April 2020

    The Norwegian Porphyria Centre (NAPOS).
    Available at:
    Last revised: 22 September 2018
    Last accessed: 08 April 2020

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