Porphyria Overview
Q: Should doctors be informed that an individual has porphyria,
even if it is latent?
A: Yes! The diagnosis of porphyria is always an important item of medical information,
even when there are no symptoms. It may, for example, influence the choice of
drugs to treat other conditions, the choice of anesthesia for surgery, or dietary
recommendations.
Q: Does surgery or pregnancy pose additional risks?
A: Again, this depends on the type
of porphyria. Surgery may increase the risk of an attack of the "acute" porphyrias.
This risk can be greatly reduced if certain precautions are taken.
Your surgeon and/or anesthesiologist may wish to consult a porphyria
expert prior to hospitalization for surgery. Such consultation
may also be helpful during pregnancy. Although attacks of "acute" porphyria
can occur during pregnancy, the risk appears to be less than was
formerly believed. Treatment of acute attacks during pregnancy
is quite feasible.
 Q: What drugs are safe and unsafe?
A: The following are only
partial lists of drugs that are potentially dangerous and probably
safe in: Acute Intermittent Porphyria, Variegate Porphyria, Hereditary
Coproporphyria and ALAD-Porphyria.
Harmful Drugs
The following is a partial list of drugs that are potentially dangerous.
- Alcohol
- Anti-epilepsy drugs
- Barbiturates1
- Birth control pills
- Calcium channel blockers4
- Carbamazepine1
- Carisoprodol1
- Clonazepam
- Danazol1
- Diclofenac1
- Diones
- Trimethadione
- Paramethadione
- Ergots
- Ethchlorvynol1
- Felbamate
- Glutethimide1
- Griseofulvin1
- Mephenytoin
- Meprobamate1
- Methyprylon
- Metoclopramide1
- Primidone1
- Progesterone1
- Pyrazinamide1
- Pyrazolones
- Rifampin1
- Sedatives
- Succinimides
- Ethosuximide
- Methsuximide
- Sulfonamide-antibiotics1
- Tranquilizers
- Valproic acid1
Safe Drugs
The following is a partial list of drugs that are probably safe.
- Acetaminophen
- Aspirin
- Atropine
- Bromides
- Cimetidine
- Chloral hydrate
- Estrogens1,3
- Glucocorticoids
- Insulin
- Narcotic analgesics
- Penicillin and derivatives
- Phenothiazines
- Ranitidine1,2
- Serotonin Reuptake Inhibitors (anti-depressants)
- Streptomycin
1 Porphyria is listed as a contraindication, warning, precaution,
or adverse effect in 1994 U.S. labeling for these drugs.
2 Although porphyria is listed as a precaution in U.S. labeling
for this drug, it is regarded as safe by other sources.
3 There is little evidence that estrogens alone are harmful
in acute porphyrias. They have been implicated as harmful based mostly on
experience with estrogen-progestin combinations and because they can exacerbate
porphyria cutanea tarda. Some patients with AIP, HCP, VP, and ADP may tolerate
a low dose estrogen patch.
4 There is strong evidence in laboratory studies and some clinical
evidence that these agents may be harmful.
The text of this page was prepared by Karl E. Anderson, M.D. and Douglas
E. Goeger, Ph.D. The University of Texas Medical Branch at Galveston.
Also see:
Recommendations about drugs for these porphyrias are based on experience
with the porphyria patients in whom attacks have been caused by drugs and
by tests in animals that have experimental porphyria. Since most commonly
used drugs have not been tested, they should be avoided if at all possible.
If a question of drug safety arises, a physician or medical center specializing
in porphyria should be contacted. A list of these institutions may be procured
from this foundation.
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