Acute Porphyrias

There are four types of acute hepatic porphyrias (sometimes collectively called AHP), all of which have similar symptoms and treatments:

  • Acute Intermittent Porphyria (AIP) is the most common

  • Variegate Porphyria (VP)

  • Hereditary Coproporphyria (HCP)

  • ALAD-Deficiency Porphyria (ADP) is extremely rare

It is believed that the symptoms of acute porphyrias are caused by a build-up of a molecule called ALA (a porphyrin precursor), which damages your nervous system. In some types of acute porphyria, other porphyrin molecules can also build up, causing skin blisters.

  • Acute hepatic porphyrias will look different in every patient. They are generally characterized by acute “attacks” that take place over several days and then resolve. Most individuals do not have symptoms between attacks, but the symptoms can become chronic for some. Frequency of attacks can also vary- some people will only ever have one attack, and some will have attacks every few weeks. Because of normal hormone fluctuations, women are more likely than men to have attacks.

    It is rare for attacks to happen before puberty. For most, the first attack will happen between late teens and early 40’s.

    Abdominal pain is the most common symptom in an attack, however some people will only experience psychiatric symptoms- this can lead to misdiagnosis and delays in care.

    Acute porphyria attack symptoms can include:

    • Severe abdominal pain

    • Severe pain in the chest, back, arms and legs

    • Nausea

    • Vomiting

    • Constipation and urinary retention

    • Muscle weakness, numbness or paralysis- often beginning in shoulders and hips

    • Tachycardia (fast heart rate) and hypertension (high blood pressure)

    • Insomnia (difficulty sleeping)

    • Anxiety, depression

    • Confusion, hallucinations (affecting any of the five senses), paranoia, psychosis

    • Seizures

    • Hyponatremia (low salt) and hypomagnesemia (low magnesium)

    • Urine may darken or redden when exposed to light

    HCP and VP may have cutaneous (skin) manifestations.

    In HCP, these symptoms tend to happen at the same time as attacks. Some people, particularly with VP, will only have skin symptoms and never have an attack. The skin symptoms include:

    • Skin lesions, blistering, pain, burning and itching on skin that is most frequently exposed to sun (usually hands and face)

    • Fragile skin, milia (tiny white bumps or cysts) on sun-exposed areas

    • Discoloured (excessively light or dark) scars

    • Excessive hair growth

  • When experiencing symptoms of an acute porphyria attack, it is important to collect samples quickly and perform testing to identify the type of porphyria and start treatment.

    Getting a diagnosis of acute hepatic porphyria can be difficult once the attack subsides as levels of porphyrins and porphyrin precursors will be highest at the beginning of an attack and then decrease back to normal levels over 14 days. If it has been more than 14 days since the attack, or you no longer have symptoms, you may need to wait until symptoms return to test again. A negative test in these circumstances does not necessarily rule out porphyria.

    Testing urine for ALA/PGB is necessary to identify if you have an acute hepatic porphyria. However, testing in a combination of samples - urine, blood plasma and feces- is required to identify the specific type of acute hepatic porphyria (see below). These specialized tests should be conducted by a specialized laboratory, and it is strongly recommended that the lab be consulted prior to ordering the tests.

    TESTS FOR ACUTE HEPATIC PORPHYRIAS

    Urine ALA/PBG: The first test required to determine if acute hepatic porphyria is present is a random urine test for ALA and PBG testing. During an attack, levels of PBG and ALA are significantly higher than normal, and this test is sufficient to confirm that an acute hepatic porphyria (eg. AIP, VP, HCP) is present. ADP is the rarest form of acute hepatic porphyria, and the only type where PBG is normal, but ALA will be elevated.

    Important things to know about with urine PBG/ALA testing:

    • A sufficiently elevated PBG level in urine is sufficient to diagnose the presence of an acute hepatic porphyria, but additional testing is needed to determine the specific type of porphyria.

    • It is important that the sample is handled properly to ensure accurate results. Failure to do so can result in a false negative result. For example:

      • Urine samples should be protected from light- either kept in a brown container or wrapped in foil.

      • Urine samples should be kept cold- refrigerated for up to two days or frozen for up to a month.

    • After an attack levels of PBG and ALA in urine will decrease and can return to normal levels within 2 – 3 weeks for VP and HCP. However, with AIP, ALA/PBG levels may remain elevated for a month or more.

    • Because of the importance of getting tested as soon as possible, 24-hour tests are not recommended. During an attack, ALA/PBG levels will be high enough to detect in a random urine sample.

    Plasma Porphyrin Fluorescence Scan: A plasma sample for Plasma Porphyrin Fluorescence Scan testing should also be sent with a random urine for ALA/PBG testing.

    Plasma Porphyrin Fluorescence Scan is a test that measures total porphyrins in the plasma. It is the gold standard test for diagnosing VP since, with VP, plasma porphyrin levels often remain high for months or years after an attack. Like urine ALA/PBG testing, plasma porphyrin fluorescence scan testing can also detect the presence of other porphyrins, though it cannot identify the specific type of porphyria.

    For this test, a blood sample (plasma is a part of your blood) will be collected. It is important that the sample is protected from light after it is collected, and should be kept cold.

    Porphyrin Quantitation in Feces: This is the next test to be done if either urine ALA/PBG or plasma fluorescence scan testing is positive. Measuring porphyrin and porphyrin precursors in feces is helpful for diagnosing HCP as well as ruling out other porphyria’s. For this test, a sample of feces will be collected and the levels of porphyrins in the sample will be measured:

    • HCP: coproporphyrin III concentrations will be significantly elevated (greater than 2x coproporphyrin I concentration)

    • VP: protoporphyrin concentrations will be elevated, greater than coproporphyrin

    • AIP and ADP: fecal porphyrin levels will be normal or slightly increased

    It is important that fecal samples are protected from light after they are collected and kept cold or frozen when transported to the lab.

    Porphyrin Quantitation in Urine: This test can also be done if either urine ALA/PBG or plasma florescence scan testing is positive, and is helpful for diagnosing AIP, as well as identifying other non-acute porphyria’s that may be present; for example, PCT, CEP and EPP. On its own, total urine porphyrin quantitation is not sufficient to diagnose porphyria. This is because urine porphyrins may be elevated in other conditions, such as gastrointestinal bleeds or use of certain medications.

    For this test, a random urine sample is collected, and porphyrin and porphyrin precursors are measured to help identify the specific porphyria. It is important that the urine sample is protected from light after it is collected and kept cold during transport to the lab.

    Genetic Testing: Unless you have a family member with a confirmed diagnosis of an acute porphyria, genetic testing is not generally recommended. For more information, see How is porphyria diagnosed?

    WHERE TO START

    If an acute hepatic porphyria is suspected, have your physician request a random urine ALA/PBG test and a plasma porphyrin fluorescence scan test. Obtain urine and plasma samples soon after an attack and send to the lab for analysis. If the ALA/PBG and/or the plasma porphyrin fluorescence scan results come back positive, additional testing is required to identify the specific type of porphyria present (see above).

    The testing laboratory will provide further guidance as to which samples and tests, urine or fecal porphyrin quantitation, are required to identify the specific type of porphyria. This may involve testing both/either urine or feces.

  • Acute hepatic porphyria attacks can sometimes be life-threatening. It is important to seek medical care, especially if you are unable to eat/get adequate nutrition or if you are experiencing paralysis/weakness.

    Many acute hepatic porphyria patients have had negative experiences when seeking care. To get the care you need, it is helpful to:

    In general, treating an acute attack should include:

    • Checking that your symptoms are not from another cause (ex. appendicitis)

    • Treatment with hemin. If you do not have a confirmed diagnosis or if your symptoms are not consistent with previous attacks, they may need to confirm high levels of urinary PBG/ALA before beginning hemin treatment.

    • If hemin is unavailable or your diagnosis hasn’t been confirmed, treatment with a glucose infusion.

    • Treating your symptoms, including pain, nausea, constipation, agitation and elevated heart rate with safe drugs- a list of recommended safe drugs is included in the Ipnet guidelines

    • Stopping any unsafe medications

    • Treating any infections

    • Monitoring sodium and other electrolyte levels, and ensuring adequate nutrition

    If you have recurring attacks, it is important that these are documented. In order to be prescribed some treatments for acute hepatic porphyrias, you may need to have had a minimum number of attacks requiring medical care within a year.

    MORE RESOURCES

    The following resources were created for health professionals, so the language may be technical:

  • For most, acute hepatic porphyria is managed through avoiding triggers and maintaining an appropriate diet (see Living with Porphyria) and with treatment with hemin during attacks. Additional medications may be prescribed to address specific symptoms- these should always be checked in the safe drug database before being taken.

    When management through lifestyle changes isn’t enough and attacks are recurrent, there are several other treatment options that may be considered.

    AVOIDING ATTACK TRIGGERS

    A key part of managing porphyria is avoiding triggers, particularly unsafe drugs, alcohol, infections and low-carb/fasting diets. See Living with Porphyria (below) for more information.

    HEMIN (PANHEMATIN, NORMOSANG)

    Hemin suppresses the heme pathway and is used to reduce the severity and length of attacks. Panhematin is available across Canada- hospitals can order it through Canadian Blood Services or Hema-Quebec (see Accessing Treatments). During an attack, you will receive several infusions over the course of several days. Hemin is delivered intravenously into a big vein or a central line. Because it can cause inflammation of the veins, injection sites may need to be moved or a central catheter inserted. The most common side effects are swelling and pain at the injection site, and inflammation of the vein.

    Hemin is also sometimes used prophylactically (to prevent attacks) for people with recurrent attacks. Unfortunately, while hemin works well in the short term, ongoing use has side effects and challenges that limit its long term use. Because hemin degrades the veins it's injected into, eventually the possible injection sites will be used up. Liver inflammation, iron overload and chronic inflammation can occur. Chronic inflammation may actually contribute to ongoing attacks or chronic symptoms.

    GLUCOSE INFUSIONS

    Treatment with glucose infusions has generally been replaced with hemin for acute attacks. This treatment is still sometimes used, however, if hemin is unavailable or a diagnosis hasn’t been confirmed ( guidelines for administering glucose). In Canada, regular infusions are sometimes also used to prevent attacks.

    GIVOSIRAN (GIVLAARI)

    Givosiran (Givlaari) is a new treatment for people who suffer from recurrent attacks and can reduce or eliminate attacks. It is delivered by a monthly injection.

    To qualify for access to Givosiran , you may have to meet certain criteria, such as a minimum number of attacks in the last year that required medical attention, and a confirmed diagnosis. For more information see Accessing Treatments.

    HORMONE INHIBITORS

    Recurrent attacks that are related to menstrual cycles are sometimes treated with gonadorelin (GnRH) analogues. These drugs stop your body from producing progesterone and estrogen, which are the major hormones regulating your menstrual cycle. The impact and side effects are similar to menopause, and include hot flashes, headaches, fatigue and low libido. Long term use can also impact bone-density.

    LIVER TRANSPLANT

    For debilitating recurrent attacks that are not responsive to other treatments, orthotopic liver transplants- where the whole liver is replaced- are a last resort option. They are considered last resort because, while transplants stop attacks entirely, they are risky procedures with a high potential for others serious health impacts.

  • Acute hepatic porphyrias can give you a higher risk of long term health complications.

    In general, the likelihood of long term impacts are higher if you have porphyria attacks, particularly recurrent attacks. There are also some people with porphyria who have never had symptoms but have a high level of porphyrins in the body all the time (referred to as asymptomatic high excreters or ASHE)- it is unknown if these high levels will increase the risk of complications.

    CHRONIC PAIN AND PARALYSIS

    Attacks can cause permanent damage to nerves, resulting in chronic pain. Nerve damage can also affect your limbs and cause weakness or paralysis. Physiotherapy may be helpful to help recover after an attack. There is more discussion of chronic pain in Living with Acute Hepatic Porphyria below.

    ANXIETY AND DEPRESSION

    Anxiety and depression are common for people with acute hepatic porphyria. There is more discussion of the mental health impacts of porphyria in Living with Acute Hepatic Porphyria.

    CHRONIC KIDNEY DISEASE

    While the exact relationship isn’t well understood, there is an increased risk of chronic kidney disease for people who experience porphyria attacks.

    If you experience porphyria attacks, your kidney function (glomerular filtration rate or eGFR) should be checked annually. If your kidney function declines, you should be referred to a nephrologist (kidney doctor).

    You may want to discuss steps you can take to protect your kidneys with your doctor. Some things you can do include:

    • Working with a doctor to manage high blood pressure

    • Getting prompt treatment for urinary tract infections

    • Limiting the use of NSAIDS (ex. aspirin, ibuprofen) and acetaminophen (ex. tylenol), and some types of antibiotics

    • Managing the risk factors for Type II diabetes

    • Regular kidney function monitoring if you are on Givosiran

    Generally, the decline in kidney function is slow and unlikely to become end stage renal disease.

    CHRONIC HYPERTENSION (HIGH BLOOD PRESSURE)

    High blood pressure is common during attacks and will generally return to normal as the attack subsides. If you suffer from attacks, your blood pressure should be monitored regularly and treated if it is high. This is important because chronic high blood pressure can stress your kidneys. It does not appear that, outside of attacks, porphyria is the cause of high blood pressure.

    LIVER CANCER

    While still rare, people who’ve had porphyria attacks are at higher risk of a type of liver cancer called hepatocellular carcinoma. Those with consistently high ALA/PBG levels but no symptoms may also be at risk. Those with latent porphyria (no attacks) are not at increased risk.

    Like with many cancers, the prognosis for hepatocellular carcinoma is much better if it is caught early. If you have attacks, it is recommended that after the age of 50, an ultrasound of your liver should be conducted every 6-12 months to screen for this cancer.

    To minimize other risk factors, people with acute porphyria should also be vaccinated against Hepatitis A and B.

    FURTHER READING

    These resources are written for medical professionals so the language may be technical:

  • Learning more about your condition can help you understand how to manage your porphyria and advocate for yourself. Here are some additional resources that you may find helpful:

    Created for medical professionals, so the language and terms may be technical:

Living with Acute Hepatic Porphyria

Most people with an acute hepatic porphyria will experience attacks very rarely, if ever. For some however, attacks may happen repeatedly or become chronic. There are important steps you should take to lessen the risk of future attacks and long term complications. 

Medical Alert bracelets or wallet cards are recommended for acute hepatic porphyria- particularly if you have a history of attacks.

  • Attacks can be triggered by a wide range of things- including drugs, diet, hormone fluctuations, illness and stress. In order to reduce the likelihood of an attack, people with acute hepatic porphyria should avoid:

    UNSAFE DRUGS

    Many drugs, including over-the-counter and herbal remedies, may not be safe if you have porphyria.

    • Consult with your doctor and check the safe porphyria drug list to make sure you are not taking any unsafe medications.

    • Some medications in the database are suspected to be unsafe, but there is not enough information to be sure either way. These should be used with caution, particularly if you have had attacks.

    • Common medications that can trigger porphyria attacks include: many forms of birth control (especially with progesterone), Gravol (dimenhydrinate), and sulfa drugs, among others.

    • Sometimes the risk of taking a potentially unsafe medication may need to be balanced with the risk of not addressing a different health condition- your doctor may wish to consult with a porphyria specialist when developing a treatment plan.

    ALCOHOL AND SMOKING

    It is particularly important to avoid alcohol if you’ve had attacks in the past, though it is advisable to avoid or moderate alcohol even if you haven’t had an attack. If you do decide to drink, keep the intake low.

    FASTING, KETO AND LOW CALORIE DIETS

    If you must fast (ex. before surgery) or cannot get adequate nutrition because of illness, intravenous fluids, including glucose should be administered. This precaution should be taken even if you do not generally have attacks.

    PHYSICAL AND EMOTIONAL STRESS

    Infections (a physical stressor) can trigger attacks, it is recommended that people with acute hepatic porphyria get vaccinations to prevent acute, preventable infections, including: annual flu shots and vaccinations to protect against covid-19, diphtheria, pertussis and tetanus, hepatitis A and B, booster shots for tetanus at least every ten years, and for those who have had chicken pox, the vaccination to protect against development of shingles.

  • In general, it is recommended that people with acute hepatic porphyria eat a varied and balanced diet with adequate carbohydrates. It is important to eat regularly and avoid fasting, calorie restriction and diets with low carbohydrates such as keto or Atkins. Besides alcohol, there is currently no evidence that any other foods need to be avoided.

    Carbohydrates during attacks. Increasing your glucose intake when you start to experience symptoms may help suppress an attack. You can do this by adding sugar or dextrose powder to juice or Gatorade, sucking hard candies, etc. If you unable to get adequate carbohydrates because of experiencing nausea or diarrhea seek medical attention.

    Weight loss. Rapid weight loss, calorie restriction, fasting, low-carb and keto diets can trigger an attack. Losing weight should be done slowly and in consultation with your doctor and dietician.

    Trigger foods. While there currently isn’t any evidence that particular foods can trigger porphyria attacks, some foods- such as charbroiled meat, cabbage and brussel sprouts- do have properties that activate the heme pathway and could contribute to an attack. However, you’d likely need to eat a very large quantity in order for this to have any effect. It is also possible to have food allergies and sensitivities that will cause symptoms similar to porphyria. You may want to keep a food journal and try eliminating certain foods to see if your symptoms improve.

    Nausea. Nausea can make it difficult to get adequate nutrition. When nauseous, try eating small amounts of easy to digest foods such as toast, rice, cereal, yogurt and banana often. Avoid acidic foods, most fruits, tea and coffee, and drink water to stay hydrated.

    Constipation. Constipation is also common with porphyria. Try fruits and vegetables, drinking plenty of water and moving more (walking, exercise).

    Supplements. In general, if you eat a well balanced diet you should not need vitamin or mineral supplements.

    • If you have skin symptoms and need to minimize your exposure to light, Vitamin D supplementation is recommended

    • Iron deficiency is common in women and is not caused by porphyria. However, iron supplements should only be taken if medically advised, because they may impact heme synthesis.

  • In addition to the porphyria itself- which can cause anxiety, depression, confusion and hallucinations- the experience of having porphyria can also have a profound impact on your mental health.

    Many people with porphyria have had negative, sometimes traumatic, experiences in the medical system, including being told that their symptoms are “in their head”, having their care needs minimized or ignored, and having care delayed or denied. Family members and friends may also minimize or disbelieve their experiences. Porphyria can also be isolating: you may not know anyone else with porphyria and it can be hard to maintain relationships while managing symptoms or avoiding sun exposure.

    It is important to look after your mental health. In addition to general health advice such as eating well, practice good sleep hygiene and exercising regularly, you may find the following helpful:

    • Ask your doctor for support to manage anxiety and depression symptoms

    • Seek professional support from a counsellor or psychologist

    • Connect with others who have similar experiences: read stories, attend patient gatherings and join supportive online groups

    • Incorporate meditation or other practices into your daily routine

  • Insomnia is a common challenge for people with acute hepatic porphyria. Some strategies that you may find helpful:

    • Avoid stimulants like caffeinated coffee, tea and pop in the afternoon and evening.

    • Get some exercise during the day, but not too close to bedtime

    • Avoid rich foods before bed.

    • Aim to go to bed and wake up at the same time each day.

    • Develop a pre-bedtime routine to help you relax and signal that bedtime is coming. It could include a warm bath or shower, meditation or using asmr noises.

    • Set up your room to sleep. Keep your room cool, dark and quiet. Black out curtains or a sleep mask can reduce light. White noise machines or earplugs can reduce noise. A comfortable pillow and mattress are also important.

    • Keep your bed for sleeping. Don’t read or watch TV in bed. If you aren’t able to sleep, get up, and read a book or listen to soothing music until you feel sleepy.

    • Try not to worry. It can be hard to silence all those niggling thoughts before bed. Writing a list can help offload them from your mind. Some people find a distraction like listening to an audiobook with a sleep timer can help them drift off.

    • Try a sleep app. There are a number of apps designed to help you sleep: some play soothing noises, offer breathing exercises or guided meditation, or will read you a story to help you fall asleep.

    • Talk to your doctor. They may be able to prescribe you a sleep aid.

  • Repeated (recurrent) attacks can result in chronic pain. It is believed that this pain is the result of nerve damage caused by attacks. The pain can feel similar to an attack, but is not responsive to hemin or opiates in the same way. If you are experiencing ongoing pain, medication for nerve pain may help. Some patients also report that cannabis products are helpful. You may also want to try:

    • Asking for a referral to a pain specialist

    • Keeping a record of your pain to share with your doctor. There are several apps that can help keep track of and manage your pain.

    • Moving more. It can be something simple like going for a walk, doing gentle yoga or tai chi, or something more intense.

    • Practicing mindfulness or meditation.

    • Getting a massage or acupuncture.

  • It is important that prior to any procedure, the surgeon and anesthesiologist review your medications and anaesthetics to ensure that they are safe for porphyria. Local anaesthetics used by dentists should also be checked to ensure safety.

    It is often required to fast before a procedure. Your doctor should give consideration to preventing a fasted state from triggering an attack. Precautions may include: allowing clear liquids up to two hours before surgery, scheduling the surgery early in the day and using intravenous glucose if you are unable to eat afterwards.

    Gastric bypass or reduction surgery is not safe and should not be attempted. These surgeries have a similar effect to fasting or dieting, and can trigger attacks.

    If you have VP or HCP and are sensitive to light, additional precautions may need to be taken:

    • The blue lasers used by dentists for cavities can burn your gums. Care should be taken when directing the light.

    • Bright surgical lights should generally be safe, however, the surgical team should be made aware of your light sensitivity and yellow filters over lights can be used to reduce risk, particularly for long surgeries.

    • The lights used for endoscopies, laser eye treatments and laser hair removal have been used with no reported problems.

    ADDITIONAL RESOURCES

  • If you have VP or HCP you may experience skin symptoms. These symptoms are caused by light, usually sunlight, shining on your skin. It is important to know that not all sun protection advice and products will work to protect your skin. This is because most sun protection is related to UV light, and the type of light that triggers porphyria skin symptoms is blue-violet light. Light is often referred to by its wavelength: the blue-violet wavelengths that affect porphyria are around 400 nm (~370-430 nm).

    Blue-violet light is present in sunlight and can also be found in fluorescent and some LED lights, computer and phone screens. Light that is passing through a window, reflected off of water or snow can also trigger symptoms. Most incandescent light and many LEDs are safe.

    Currently the best way of managing skin symptoms is to avoid blue-violet light. Treatments that work for attacks (hemin) and other types of skin porphyrias (phlebotomies, chloroquine) do not help for VP and HCP.

    Some strategies and tips to protect yourself blue-violet light include:

    • Clothing: double layers or thick, dark fabrics will block out more light. Long sleeves, wide-brimmed hats, sunglasses, buffs and gloves can help keep you covered. Many people find clothing specifically for sun and UV protection to be helpful.

    • Protecting your hands: Skin on your hands is often exposed to light and may be delicate, and more prone to injury. Gloves can both protect your hands from light and prevent injuries when doing outdoor activities like gardening.

    • Stay in the shade. You can also consider carrying an umbrella to make your own shade.

    • Sunscreen: most sunscreens don’t block blue-violet light and won’t protect your skin from porphyria. Some people find opaque or mineral sunscreens helpful. These sunscreens sit on top of your skin and form a reflective barrier. Some are tinted, which can help them blend in better.

    • Windows: regular windows do not block blue-violet light. Windows can be tinted or covered with vinyl films that filter out blue light. Car windows can also be tinted- though it is important to check your local laws about window tinting.

    • Screens: most phones and computer screens will let you turn on a “night mode” that reduces blue light.

    • Ask for accommodations: under human rights legislation in Canada, employers and schools are required to provide reasonable accommodations for disability. If there are steps your employer could take, such as changing lights, adding window films or moving your workspace away from windows, you can make a request and your workplace should take reasonable steps to accommodate you.

  • Pregnancy is usually well-tolerated for acute hepatic porphyrias. There are some special considerations, however, so it is recommended that you get a pre-conception evaluation and are followed by a high-risk obstetrician throughout your pregnancy. Some things to be aware of:

    • Pregnancy and post-partum can trigger attacks. It is believed this is due to hormone changes.

    • It is important to stay hydrated and get adequate nutrition. Morning sickness and nausea can make it difficult to get adequate nutrition, which can also contribute to an attack.

    • If you do have an attack, hemin is safe to use during pregnancy and breastfeeding.

    • Fertility treatments may trigger attacks and should be used with caution.

    • People with a history of recurrent attacks may be at higher risk of miscarriage.

    Some people are concerned about passing their porphyria genes on to their children. You can ask for a referral to a genetic counselor to help with your family planning.

  • Most types of acute hepatic porphyria (AIP, VP and HCP) are called low-penetrance autosomal dominant conditions. What this means is:

    • Low-penetrance: The defective gene does not always result in symptoms. Most people (more than 90%) with an AHP gene will never show any symptoms. These non-symptomatic people are called latent carriers.

    • Autosomal: The sex of the person will not affect your likelihood of passing on the gene (the gene is not on a sex chromosome). Because everyone has two copies of each autosomal gene, the likelihood of a parent passing on an autosomal gene to a child is 50%.

    • Dominant: Everyone will have two copies of each type of autosomal gene. If the gene is dominant, you will only need one copy of the gene to be defective in order to have porphyria.

    Therefore, if you have AIP, VP or HCP, there is a 50% chance of passing the gene on to a child, though because of the low-penetrance, they may never have symptoms.

    ALAD-deficiency (ADP) is an autosomal recessive condition. This means that two copies of the defective gene are required to cause symptoms. As a result ADP is very rare. If you have ADP, all your children will be carriers of the gene.

  • It is important to remember it is possible to have other health conditions in addition to your porphyria. If you are experiencing health issues, it is important to discuss them with your doctor. Sometimes both patients and doctors may assume that any symptoms are related to porphyria, and this can mean that other conditions, food sensitivities or common health issues are neglected.

Safe/Unsafe Drugs

Many drugs are, or are suspected to be, unsafe for people with acute hepatic porphyrias. 

  • Don’t assume herbal remedies, supplements and over-the-counter medications are safe.

  • Review any new medication with your health professional using the safe drug databases prior to beginning use. Sometimes the risk of taking a potentially unsafe medication may need to be balanced with the risk of not addressing a different health condition- your doctor may wish to consult with a porphyria specialist when developing a treatment plan.

  • Recommendations for safe drugs to use during attacks are available from the International Porphyria Network.

  • Gravol (dimenhydrinate) is difficult to find in the databases and is not safe for acute porphyria. It is a common anti-nausea medication available without prescription in Canada and is often administered in hospitals (through IV).

Databases

  • PorphyriaDrugs.com

    • Compiles the results from several databases

    • Available as an app

    Access

  • Nordic Drug Database (NAPOS)

    Access NAPOS

  • American Porphyria Foundation (APF)

    Access APF