Acute Porphyrias

Question 1

The acute porphyrias are ______________ disorders of ____________ biosynthesis

Answer 1

Hereditary

Haem

Question 2

What are the different acute porphyrias? (4)

Answer 2

1. Acute intermittent porphyria
2. Variegate porphyria
3. Hereditary coproporphyria
4. 5-aminolaevulinic acid dehydratase deficiency porphyria

Question 3

What is the prevalence of acute porphyrias?

Answer 3

1 in 75 000

Question 4

Great care must be taken when ___________ for patients with acute porphyria, since certain ___________ can induce acute porphyric crises

Answer 4

prescribing

drugs

Question 5

Since acute porphyrias are hereditary, _______________ should be screened and advised about the potential danger of certain drugs

Answer 5

relatives of affected individuals

Question 6

Where there is no safe alternative, drug treatment for serious or life-threatening conditions ________________ patients with acute porphyria

Answer 6

should not be withheld from

• Where possible, the clinical situation should be discussed with a porphyria specialist for advice on how to proceed and monitor the patient

Question 7

________________ is administered by short intravenous infusion as haem replacement in moderate, severe, or unremitting acute porphyria crises

Answer 7

Haem arginate

Question 8

What are the clinical manifestations of acute porphyria? (8)

Answer 8

1. Severe abdominal pain
2. Pain in chest, back, or legs
3. Constipation or diarrhea
4. N/V
5. Muscle pain, tingling, numbness, weakness, or paralysis
6. Red or brown urine
7. Mental changes such as anxiety, confusion, hallucinations, disorientation, or paranoia
8. Sensitivity to sunlight

Question 9

What causes the symptoms of acute porphyrias?

Answer 9

Buildup of porphyrin and porphyrin precursors in the liver, skin, and other body tissues

Question 10

What happens in acute porphyria attacks eg those induced by certain drugs?

Answer 10

Something eg a drug stimulates the enzymes in the porphyrin pathway, leading to a rapid increase in porphyrins in the blood and tissues

This triggers a period of severe symptoms that may require hospitalization and can be life-threatening without treatment

Attacks often start with severe abdominal, back, or thigh pain and can last 1-2 weeks

May cause neurological problems such as paralysis

Question 11

How does haem arginate help reduce the symptoms of acute porphyria?

Answer 11

Because it is a complete haem, this drug slows down the production of porphyrins, thereby reducing the number of toxic intermediate circulating and depositing in the system

Question 12

What are the drug GROUPS that are considered unsafe to take for patients with acute porphyria? (11)

Answer 12

1. Anabolic steroids
2. Antidepressants including MAOIs and TCAs
3. Barbiturates
4. Hormonal contraceptives, progestogens, and HRT
5. Imidazole antifungals
6. NNRITs
7. Proteases inhibitors
8. Sulfonamides
9. Sulfonylureas
   * *(glipizide and glimepiride are thought to be SAFE)
10. Taxanes
11. Triazole antifungals
    * *(topical antifungals are thought to be safe due to low systemic exposure)

Question 13

Which sulfonylureas are considered safe for use in patients with acute porphyrias? (2)

Answer 13

1. Glipizide

2. Glimepiride

Question 14

Although systemic antifungals are known to trigger attacks of acute porphyria, ______________ use is considered safe

Answer 14

Topical

Question 15

In addition to the drug groups considered unsafe for use in acute porphyria, how many other drugs are known to trigger acute attacks?

Answer 15

76

Check the BNF treatment summaries page OR contraindications of specific drugs