How to reduce the risk of hypersensitivity reactions due to allopurinol?

In 2020, ACR's gout treatment guidelines and the newly released "Gout Grass-roots Rational Medication Guidelines" recommended allopurinol as a first-line uric acid-lowering drug, but allopurinol can cause fatal hypersensitivity reactions.

As a first-line recommended drug, allopurinol, how safe is allopurinol? How to reduce the risk of hypersensitivity reactions?

Question response

Q1What is allopurinol?

1.

2.

① Primary and secondary hyperuricemia, especially hyperuricemia caused by excessive uric acid production;

② Patients with recurrent or chronic gout;

③Tophi;

④Uric acid nephrolithiasis and (or) uric acid nephropathy;

⑤ Hyperuricemia with renal insufficiency

3.

①Adult: The initial dose is 50mg/time, 1~2 times/d, can be used every week

Increase by 50~100mg to 200~300mg/d, orally in 2~3 times

Determine whether to increase by monitoring blood and urine uric acid levels every 2 to 4 weeks

The dosage for patients with CKD 1-2 should not exceed 800 mg; the recommended dosage for patients with CKD 3-4 is 50-100 mg/d, and the dosage should not exceed 300 mg/d; patients with CKD 5 should be used with caution

②Children : <6 years old , 50mg/time, 1~3 times/d; 6~10 years old, 100mg/time, 1~3 times/d

4.

It can cause allergic skin reactions and damage to liver and kidney function.

5.

①It can enhance the effect of anticoagulants such as dicoumarin or immunosuppressants azathioprine and mercaptopurine, and the dosage of the latter should be adjusted

②When used together with ampicillin, the incidence of rash increases;

③ When used together with cyclophosphamide, the inhibition of bone marrow is more obvious;

④Use together with uric acid can increase the possibility of kidney stone formation;

⑤ It is not advisable to take it with iron

6.

Pregnant and lactating women medication: disabled

Pediatric medication Pediatric medication: Dosage should be adjusted as appropriate
.

Medication in elderly patients: The elderly should be cautious about medication and should reduce the daily dose
.

Q2How to avoid hypersensitivity reactions to allopurinol?

1.
If conditions permit, it is recommended to screen for HLA-B*5801 gene before medication
.
If genetic screening is not possible, careful inquiry about allergy history should be made
.

2.
Start using a dose of 50 mg/d or even lower, observe carefully, and stop the drug immediately if a rash occurs
.

3.
Start with small doses

4.
Avoid combined diuretics

5.
Use with caution in patients with renal insufficiency

6.
Pay close attention to the reaction after the drug

Tips: HLA-B*5801-positive individuals need to be cautious in the application of allopurinol, but it is not impossible to apply
.
Studies have found that in the HLA-B*5801 positive population, the incidence of allopurinol-induced hypersensitivity syndrome (AHS) in people with normal renal function does not exceed 2.
7% , while the incidence in patients with renal insufficiency is as high as 18%
.
Therefore, allopurinol should be used with caution in individuals with renal insufficiency
.
The ACR guidelines recommend that the daily dose of allopurinol should not exceed 100 mg at the beginning of treatment.
For patients with renal insufficiency, the dose should be further reduced.
Some studies have found that the daily dose of allopurinol does not exceed 1.
5xGFR (mg).
, can reduce the incidence of AHS
.
Given that the median time to onset of AHS is 30 days, in the first month of initiation of treatment, special attention should be paid to the presence of rashes and other manifestations; in addition, even if AHS does not occur in the first few months of initiation of treatment, it is not possible to completely treat AHS.
Let your guard down
.

Q3

Who is suitable for allopurinol?

In individuals with normal renal function and negative HLA-B*5801, allopurinol is relatively safe
.

For HLA-B*5801-positive individuals, if the renal function is normal, the risk of AHS is higher than that of the negative individuals, but it is still possible to start treatment with a low dose, and if the renal function is insufficiency, allopurinol should be avoided as much as possible
.
At present, some medical institutions cannot perform HLA-B*5801 testing.
In this case, allopurinol can also be used, but the dose should be started from a lower level, 50 mg per day or even 50 mg every other day.
Adjust the dosage according to the decrease of uric acid
.

Q4What precautions should be taken when applying?

1.
Allopurinol cannot control the acute inflammatory symptoms of gouty arthritis and cannot be used as an anti-inflammatory drug
.

2.
Allopurinol can re-induce and aggravate the symptoms of acute arthritis when uric acid crystals are re-dissolved.
Therefore, it should be used 2-4 weeks after the gout attack is relieved.
If a gout attack occurs during drug treatment, it is not recommended to stop lowering uric acid.
drug
.

3.
Drink more water during taking the medicine, and make the urine neutral or alkaline to excrete uric acid
.

4.
This product must start with a small dose and gradually increase to an effective dose to maintain normal blood uric acid and uric acid levels, and then gradually reduce the dose and maintain the minimum effective dose for a long time.

5.
If there is any skin reaction or other signs of hypersensitivity reaction, the drug should be discontinued immediately and seek medical attention in time
.

In 2020, ACR's gout treatment guidelines and the newly released "Gout Grass-roots Rational Medication Guidelines" recommended allopurinol as a first-line uric acid-lowering drug, but allopurinol can cause fatal hypersensitivity reactions.
Many doctors are discouraged from this drug
.

In 2020, ACR's gout treatment guidelines and the newly released "Gout Grass-roots Rational Medication Guidelines" recommended allopurinol as a first-line uric acid-lowering drug, but allopurinol can cause fatal hypersensitivity reactions.
Many doctors are discouraged from this drug
.
guide

As a first-line recommended drug, allopurinol, how safe is allopurinol? How to reduce the risk of hypersensitivity reactions?

As a first-line recommended drug, allopurinol, how safe is allopurinol? How to reduce the risk of hypersensitivity reactions? question response question response

Q1What is allopurinol?

Q1What is allopurinol? Q1

1.
Drug classification: uric acid-lowering drugs
.

1.
Drug classification: uric acid-lowering drugs
.
1.
Drug classification: uric acid-lowering drugs
.

2.
Indications: for treatment

2.
Indications: for treatment 2.
Indications:

① Primary and secondary hyperuricemia, especially hyperuricemia caused by excessive uric acid production;

① Primary and secondary hyperuricemia, especially hyperuricemia caused by excessive uric acid production;

② Patients with recurrent or chronic gout;

② Patients with recurrent or chronic gout;

③Tophi;

③Tophi;

④Uric acid nephrolithiasis and (or) uric acid nephropathy;

④Uric acid nephrolithiasis and (or) uric acid nephropathy;

⑤ Hyperuricemia with renal insufficiency
.

⑤ Hyperuricemia with renal insufficiency
.

3.
Dosage:

3.
Dosage: 3.
Dosage:

①Adult: The initial dose is 50mg/time, 1~2 times/d, can be used every week

①Adult: The initial dose is 50mg/time, 1~2 times/d, can be used every week

Increase by 50~100mg to 200~300mg/d, orally in 2~3 times
.

Increase by 50~100mg to 200~300mg/d, orally in 2~3 times
.

Determine whether to increase by monitoring blood and urine uric acid levels every 2 to 4 weeks
.

Determine whether to increase by monitoring blood and urine uric acid levels every 2 to 4 weeks
.

The dosage for patients with CKD 1-2 should not exceed 800 mg; the recommended dosage for patients with CKD 3-4 is 50-100 mg/d, and the dosage should not exceed 300 mg/d; patients with CKD 5 should be used with caution
.
Pay attention to the principle of using the lowest effective dose to maintain blood uric acid below the target level
.
 

The dosage for patients with CKD 1-2 should not exceed 800 mg; the recommended dosage for patients with CKD 3-4 is 50-100 mg/d, and the dosage should not exceed 300 mg/d; patients with CKD 5 should be used with caution
.
Pay attention to the principle of using the lowest effective dose to maintain blood uric acid below the target level
.
 

②Children : <6 years old , 50mg/time, 1~3 times/d; 6~10 years old, 100mg/time, 1~3 times/d
.
The dose can be adjusted as appropriate
.

②Children : <6 years old , 50mg/time, 1~3 times/d; 6~10 years old, 100mg/time, 1~3 times/d
.
The dose can be adjusted as appropriate
.
child

4.
Adverse reactions and treatment:

4.
Adverse reactions and treatment: 4.
Adverse reactions and treatment:

It can cause allergic skin reactions and damage to liver and kidney function.
In severe cases, hypersensitivity syndromes such as fatal exfoliative dermatitis can occur
.
If the rash is extensive and persistent, the symptomatic treatment is ineffective and has a tendency to worsen, or the white blood cell count decreases, thrombocytopenia, anemia or bone marrow suppression must be discontinued
.
Other gastrointestinal reactions such as nausea, vomiting, diarrhea, and peripheral neuritis are often transient and disappear after drug withdrawal
.
The drug should be started with a small dose, and the blood routine and liver and kidney function should be checked regularly during the treatment period.
If a rash occurs, it is recommended to stop the drug immediately
.

It can cause allergic skin reactions and damage to liver and kidney function.
In severe cases, hypersensitivity syndromes such as fatal exfoliative dermatitis can occur
.
If the rash is extensive and persistent, the symptomatic treatment is ineffective and has a tendency to worsen, or the white blood cell count decreases, thrombocytopenia, anemia or bone marrow suppression must be discontinued
.
Other gastrointestinal reactions such as nausea, vomiting, diarrhea, and peripheral neuritis are often transient and disappear after drug withdrawal
.
The drug should be started with a small dose, and the blood routine and liver and kidney function should be checked regularly during the treatment period.
If a rash occurs, it is recommended to stop the drug immediately
.

5.
Drug Interactions:

5.
Drug Interactions: 5.
Drug Interactions:

①It can enhance the effect of anticoagulants such as dicoumarin or immunosuppressants azathioprine and mercaptopurine, and the dosage of the latter should be adjusted
.

①It can enhance the effect of anticoagulants such as dicoumarin or immunosuppressants azathioprine and mercaptopurine, and the dosage of the latter should be adjusted
.
immunity

②When used together with ampicillin, the incidence of rash increases;

②When used together with ampicillin, the incidence of rash increases;

③ When used together with cyclophosphamide, the inhibition of bone marrow is more obvious;

③ When used together with cyclophosphamide, the inhibition of bone marrow is more obvious;

④Use together with uric acid can increase the possibility of kidney stone formation;

④Use together with uric acid can increase the possibility of kidney stone formation;

⑤ It is not advisable to take it with iron
.

⑤ It is not advisable to take it with iron
.

6.
Special groups:

6.
Special groups: 6.
Special groups:

Pregnant and lactating women medication: disabled
.

Pregnant and lactating women medication: disabled
.

Pediatric medication Pediatric medication: Dosage should be adjusted as appropriate
.

Pediatric medication Pediatric medication: Dosage should be adjusted as appropriate
.

Medication in elderly patients: The elderly should be cautious about medication and should reduce the daily dose
.

Medication in elderly patients: The elderly should be cautious about medication and should reduce the daily dose
.

Q2How to avoid hypersensitivity reactions to allopurinol?

Q2How to avoid hypersensitivity reactions to allopurinol? Q2

1.
If conditions permit, it is recommended to screen for HLA-B*5801 gene before medication
.
If genetic screening is not possible, careful inquiry about allergy history should be made
.

1.
If conditions permit, it is recommended to screen for HLA-B*5801 gene before medication
.
If genetic screening is not possible, careful inquiry about allergy history should be made
.
screening

2.
Start using a dose of 50 mg/d or even lower, observe carefully, and stop the drug immediately if a rash occurs
.

2.
Start using a dose of 50 mg/d or even lower, observe carefully, and stop the drug immediately if a rash occurs
.

3.
Start with small doses

3.
Start with small doses

4.
Avoid combined diuretics

4.
Avoid combined diuretics

5.
Use with caution in patients with renal insufficiency

5.
Use with caution in patients with renal insufficiency

6.
Pay close attention to the reaction after the drug

6.
Pay close attention to the reaction after the drug

Tips: HLA-B*5801-positive individuals need to be cautious in the application of allopurinol, but it is not impossible to apply
.
Studies have found that in the HLA-B*5801 positive population, the incidence of allopurinol-induced hypersensitivity syndrome (AHS) in people with normal renal function does not exceed 2.
7% , while the incidence in patients with renal insufficiency is as high as 18%
.
Therefore, allopurinol should be used with caution in individuals with renal insufficiency
.
The ACR guidelines recommend that the daily dose of allopurinol should not exceed 100 mg at the beginning of treatment.
For patients with renal insufficiency, the dose should be further reduced.
Some studies have found that the daily dose of allopurinol does not exceed 1.
5xGFR (mg).
, can reduce the incidence of AHS
.
Given that the median time to onset of AHS is 30 days, in the first month of initiation of treatment, special attention should be paid to the presence of rashes and other manifestations; in addition, even if AHS does not occur in the first few months of initiation of treatment, it is not possible to completely treat AHS.
Let your guard down
.

Tips: HLA-B*5801-positive individuals need to be cautious in the application of allopurinol, but it is not impossible to apply
.
Studies have found that in the HLA-B*5801 positive population, the incidence of allopurinol-induced hypersensitivity syndrome (AHS) in people with normal renal function does not exceed 2.
7% , while the incidence in patients with renal insufficiency is as high as 18%
.
Therefore, allopurinol should be used with caution in individuals with renal insufficiency
.
The ACR guidelines recommend that the daily dose of allopurinol should not exceed 100 mg at the beginning of treatment.
For patients with renal insufficiency, the dose should be further reduced.
Some studies have found that the daily dose of allopurinol does not exceed 1.
5xGFR (mg).
, can reduce the incidence of AHS
.
Given that the median time to onset of AHS is 30 days, in the first month of initiation of treatment, special attention should be paid to the presence of rashes and other manifestations; in addition, even if AHS does not occur in the first few months of initiation of treatment, it is not possible to completely treat AHS.
Let your guard down
.
Tips: Studies have found that in the HLA-B*5801 positive group, the incidence of allopurinol-induced hypersensitivity syndrome (AHS) in people with normal renal function does not exceed 2.
7%

Q3

Q3
Q3

Who is suitable for allopurinol?

Who is suitable for allopurinol?

In individuals with normal renal function and negative HLA-B*5801, allopurinol is relatively safe
.

In individuals with normal renal function and negative HLA-B*5801, allopurinol is relatively safe
.

For HLA-B*5801-positive individuals, if the renal function is normal, the risk of AHS is higher than that of the negative individuals, but it is still possible to start treatment with a low dose, and if the renal function is insufficiency, allopurinol should be avoided as much as possible
.
At present, some medical institutions cannot perform HLA-B*5801 testing.
In this case, allopurinol can also be used, but the dose should be started from a lower level, 50 mg per day or even 50 mg every other day.
Adjust the dosage according to the decrease of uric acid
.

For HLA-B*5801-positive individuals, if the renal function is normal, the risk of AHS is higher than that of the negative individuals, but it is still possible to start treatment with a low dose, and if the renal function is insufficiency, allopurinol should be avoided as much as possible
.
At present, some medical institutions cannot perform HLA-B*5801 testing.
In this case, allopurinol can also be used, but the dose should be started from a lower level, 50 mg per day or even 50 mg every other day.
Adjust the dosage according to the decrease of uric acid
.

Q4What precautions should be taken when applying?

Q4 What are the precautions when applying Q4 ?

1.
Allopurinol cannot control the acute inflammatory symptoms of gouty arthritis and cannot be used as an anti-inflammatory drug
.

1.
Allopurinol cannot control the acute inflammatory symptoms of gouty arthritis and cannot be used as an anti-inflammatory drug
.

2.
Allopurinol can re-induce and aggravate the symptoms of acute arthritis when uric acid crystals are re-dissolved.
Therefore, it should be used 2-4 weeks after the gout attack is relieved.
If a gout attack occurs during drug treatment, it is not recommended to stop lowering uric acid.
drug
.

2.
Allopurinol can re-induce and aggravate the symptoms of acute arthritis when uric acid crystals are re-dissolved.
Therefore, it should be used 2-4 weeks after the gout attack is relieved.
If a gout attack occurs during drug treatment, it is not recommended to stop lowering uric acid.
drug
.

3.
Drink more water during taking the medicine, and make the urine neutral or alkaline to excrete uric acid
.

3.
Drink more water during taking the medicine, and make the urine neutral or alkaline to excrete uric acid
.

4.
This product must start with a small dose and gradually increase to an effective dose to maintain normal blood uric acid and uric acid levels, and then gradually reduce the dose and maintain the minimum effective dose for a long time.

4.
This product must start with a small dose and gradually increase to an effective dose to maintain normal blood uric acid and uric acid levels, and then gradually reduce the dose and maintain the minimum effective dose for a long time.

5.
If there is any skin reaction or other signs of hypersensitivity reaction, the drug should be discontinued immediately and seek medical attention in time
.

5.
If there is any skin reaction or other signs of hypersensitivity reaction, the drug should be discontinued immediately and seek medical attention in time
.


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