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Drug Safety

Introduction

Drugs are the most common factor precipitating the acute attack of porphyrias, and it is essential that people with the acute porphyrias avoid taking any drug which may induce an acute attack . (Of course, if you have porphyria cutanea tarda or erythropoietic protoporphyria, you need not worry as these conditions are not aggravated by drugs.)

Our list contains most drugs available in South Africa at present. Note that new drugs are constantly being introduced, and the absence of a drug from this list does not mean that its safety can be assumed.

The list is presented in two ways: in alphabetical order, and then grouped together into common indications for medication, such as Asthma, Diabetes etc. You can also print out the entire list for your reference. Check back from time to time as we do update it as new information becomes available.

Generic Names and Trade Names

Patients are often confused by the names of drugs. Every drug has two names: an official or generic name, and then one or many trade names which are the names given to their products by the different pharmaceutical companies. Our drug lists contain only generic names, and it is therefore important that you take the trouble to read the package or to ask your doctor or pharmacist for the generic name before consulting our list.

While we take every precaution, we cannot accept any responsibility for adverse experiences arising from the use of our lists.

See our disclaimer.

Topical Preparations are Safe

As a general rule, all topical preparations are safe. Thus drugs which are applied directly to the skin or into the ear and eye, or used for gargling without swallowing, are likely to be safe. Our list omits all agents used only by these routes, and comprises only those intended for systemic use. Care should be taken with rectal and vaginal preparations and drugs which are inhaled, as there may be significant absorption.

Key Status to Terms

The following are the status terms used in the list.

Use Likely to be safe and may be used freely.
Use, but with caution Though safety is not established beyond doubt, the evidence suggests that the drug is unlikely to prove unsafe in practice. It is usually safe to take such a drug.
Use only with extreme caution and if no alternative There is evidence to suggest that the drug may yet prove unsafe in practice, or grounds to suspect this may be so, or too little evidence to suggest that it may be safe. Such drugs should only be used if the expected benefits strongly outweigh the risks. If possible, use an alternative.
Avoid: high risk There is evidence that such drugs have precipitated acute attacks in patients, or other grounds for believing that the risk of an acute attack is high.
Unknown, therefore avoid There is too little evidence to draw a conclusion, and it is wisest to regard the drug as potentially hazardous and avoid its use.

Choosing the Right Drug

No porphyric patient should take any medication unless it is really necessary. Many drug-related problems involve medication which was not strictly necessary in the first place. Beware of compound medications: particularly analgesics:one of the ingredients may be dangerous, even if the others are safe.

When you do need treatment, select drugs in the order above. Before you take any drug in the last three categories, your doctor must be sure that a real need for the drug exists and that no safer alternative is possible; you can also expect to have the choice of drug discussed with you, and you should be properly informed of any risks and give your consent before you take any potentially risky medication.

The Napos Drug Database

The Norwegian Porphyria Centre (NAPOS) has designed an excellent database (in English) detailing drug safety in porphyria. We are in the process of correlating our own recommendations with theirs, and we gratefully acknowledge their work. Our website contains a direct link so that you can, if you wish look up a drug on their database directly.

Choosing the Right Drug for Specific Conditions

Please note that information on prescribing the right drug for some specific conditions, e.g. hypertension, malaria and family planning, is available on the For professionals pages.

How Will You Know if You are Reacting to the Right Medication?

Symptoms of an incipient acute attack

If you develop significant abdominal pain, that is, deep, gnawing pain and discomfort in your abdomen, you need to contact your doctor. This may be the first sign that your porphyria is becoming more active. Under these circumstances, you must not take any more of the medication until you have been absolutely reassured that the pain is not due to porphyria. If the symptoms are compelling, then you should have your urine tested for PBG, but you should not wait for a result before contacting your doctor.

Other symptoms

Any other symptom—heartburn, dizziness, nausea, drowsiness etc.—is unlikely to be as a result of porphyria. Most drugs have side-effects, and people with porphyria are no more prone to these than are normal people. Under these circumstances you may safely continue our medication, provided the side-effects are not in their own right sufficiently severe to force you to stop treatment.

When You are Forced to Take Potentially Dangerous Medication

Under some circumstance your doctor may be forced to prescribe treatment which is not definitely safe, e.g. if you develop TB or cancer. Provided you and your doctor are careful, this seldom gives problems. You need to choose the safest alternative, take your medication as prescribed, avoid taking other and unnecessary potentially dangerous substances at the same time (including alcohol and cannabis), and inform your doctor immediately if you develop pain.