Drug Fever

Comprehensive Guide to Drug Fever

Drug fever usually occurs in connection with taking medication as an undesirable side effect. In some cases, however, drug fever is a desirable side effect with therapeutic benefit. An increased body temperature due to certain medications is usually registered up to ten days after the start of therapy. Depending on the triggering drug, the drug fever can occur sooner or later.

What is drug fever?

Drug fever is defined as an increase in temperature as a result of taking medication. The reason for the febrile reaction to the preparation is often an intolerance or allergy to one or more components of the preparation. The drug can also influence the body’s thermoregulation.

This effect can even be deliberate in the case of cytostatics. In the case of drug fever, there may also be a thermal effect that was triggered by one of the substances it contains. In drug fever, a distinction must be made between allergic or intolerance reactions and substance-related effects. The latter can occur in a dose-dependent manner. If necessary, the preparation must be exchanged or dosed lower in the event of medication fever.


According to abbreviationfinder.org, the causes of drug fever can lie in the patient or in the prescribed drug. If the patient is allergic, drug fever can potentially occur in response to any prescribed drug. The drug fever can be a sign of an intolerance reaction, a real allergy or anaphylactic shock. In the latter case, the drug must be discontinued immediately.

If necessary, medical countermeasures must be initiated. In addition, an increased sensitivity to (certain) drugs can be innate. Other causes of drug fever may be due to the drug itself. For example, it can influence thermoregulation and trigger febrile attacks. In the event of a substance-related reaction, the preparation does not always have to be discontinued. In the case of drug fever, it is often sufficient to reduce the dose.

But it is also possible that the fever has an independent cause and was triggered by an inflammation. If the drug fever does not subside after down-dosing or discontinuing the prescribed drug, differential diagnostic examinations are necessary. It may then not be a drug fever.

Symptoms, ailments & signs

Typical symptoms and signs of drug fever include increased body temperature. This occurs after a week or later with a delay. A mild fever is possible, but also severe febrile effects. The drug fever can be accompanied by other symptoms and complaints.

Depending on the type and trigger of the drug fever, a blocked or runny nose may occur. The hard cold can be accompanied by sneezing attacks. The drug fever can make the patient sweat profusely and make the skin look abnormally pale. The medication can lead to noticeable rashes (exanthema) or hives (urticaria) with corresponding itching and red wheals.

Dangerous symptoms can be swelling of the mucous membranes, shortness of breath and asthma-like cough. The digestive tract and the intestinal flora can also be attacked by the active pharmaceutical ingredients. Occasionally, in addition to drug fever, diarrhea, vomiting or colic or general immune deficiency occur.


Quincke syndrome is one of the possible complications of drug fever. It is an allergic reaction to certain ingredients of the preparation. Quincke’s edema is classified as a life-threatening acute case. Typical signs of Quincke’s edema are noticeably swollen lips, swollen eyelids and difficulty breathing due to increasing swelling of the airways.

This creates asthma-like breathing difficulties in addition to drug fever. It is necessary to act quickly so that the patient does not die. Another emergency that can occur in addition to drug fever is circulatory collapse. The breakdown of the circulatory system in drug fever can be a sign of anaphylactic shock. The signs are paleness, a sudden drop in blood pressure, and a significant increase in heart rate.

Here, too, immediate action is essential. Hypersensitivity Syndrome (HSS) is a rather rare complication. In medicine it is also described as “Drug Rash with Eosinophilia and Systemic Symptoms” (DRESS) or “Drug Induced Delayed Multi Organ Hypersensitivity Syndrome” (DIDMOHS). The problem is that the symptoms of hypersensitivity syndrome can only appear a few weeks after the start of therapy. In addition to drug fever, there is often lymph node swelling and rashes all over the body.

It can lead to a severe inflammation of the throat with ulcers and swelling of the face. In addition, this condition can take a dramatic course due to organ damage. Due to the rarity of this complication, no one can currently say how often it occurs. Without immediate action, the affected patient dies as a result of inflammation of the liver. This usually leads to liver and kidney failure.

When should you go to the doctor?

Anyone who notices unusual symptoms after taking medication should always go to the attending physician or family doctor. Only they can assess whether the symptoms will pass or whether the preparation must be discontinued. Unauthorized discontinuation of the prescribed medication is not advisable. The information leaflet of the prescribed medication contains the possible side effects and interactions that medication can have.

There is often an increased risk of adverse effects such as drug fever in certain patient groups. The attending physicians often do not ask enough about which other preparations the patient is taking on a regular basis. As a result, they are often unable to assess the risks of drug fever or other adverse reactions. In addition, the patient can react allergic to certain ingredients without his or her knowledge.

If, after taking medication, the body temperature increases slightly without any further symptoms, the person concerned should observe the fever. A doctor should be called as soon as further symptoms such as rashes, respiratory problems, swelling or falling blood pressure become apparent. If necessary, the emergency doctor must be notified. It could be a crisis that needs treatment or an emergency. Drug fever is not to be trifled with. The family doctor / emergency doctor must know which preparation caused the symptoms.


Blood pressure and temperature measurements are among the simple medical diagnosis options. If the body temperature rises, it depends on how high it is. If the fever is mild, no action may be necessary. But if the fever rises above 38, it does. In addition to temperature monitoring, questioning and physical examination of the person affected is essential. It must be determined whether or not it is actually drug fever.

Other causes for the increased temperature are conceivable. A blood test provides information about various parameters. In the case of drug fever due to immunologically-related drug intolerance, neutropenia or the destruction of white blood cells (agranulocytosis) can occur. In this case, there is a high fever. As a result of the lack of white blood cells, there is a weak immune system.

This can lead to acute tonsillitis, mouth rot or dangerous blood poisoning. Therefore, after determining the body temperature and the symptoms present, all diagnostic means that make sense are to be used. Only the attending physician can assess whether the symptoms that have occurred are dangerous or temporary in nature. In any case, in the event of severe drug fever, close monitoring of the patient is recommended.

Treatment & Therapy

The treatment of drug fever is symptom-dependent. If you have a mild fever, medical intervention is unlikely to be necessary. If necessary, the preparation must be discontinued or exchanged for a better tolerated drug. A more complex procedure is required for severe drug fever. It is important to take appropriate measures to lower the fever.

The other approach in the treatment of drug fever applies especially if other symptoms and complaints are observed. Here, the triggering drug should be discontinued if possible if it is not essential for life. Prescribing a replacement drug can be problematic in the presence of severe drug fever. This could result in further medical problems. If necessary, a clinical stay is advisable in order to be able to monitor the patient closely. This measure is particularly advisable if complications arise. The treatment is otherwise based on the symptoms present.

The situation decides whether antihistamines or other measures against allergic reactions have to be used. In the event of dramatic developments, a transfer to the intensive care unit will be necessary. The organ functions can be monitored here. The patient can be ventilated if necessary. In severe allergic reactions and anaphylactic shock, high doses of adrenaline, antihistamines, or corticosteroids are given to save the patient. The quick response is crucial. Self-treatment with oral antihistamines endangers the life of the patient due to insufficient dosage.

Outlook & forecast

If the course is mild without any further symptoms or symptoms, the drug fever does not represent any further danger. If mild drug fever does not go away on its own after a few days, a doctor should be consulted. In general, if the fever is mild, the prognosis is good. It can look different when it comes to severe drug fever. In particular, if allergic or organic complaints occur, the prognosis is significantly worse.

It worsens if the person concerned discontinues the preparation without authorization, undertakes improper self-treatment or does not go to the doctor immediately. If it is suspected that it is a drug fever, medical advice is essential. It improves the prognosis and ensures that drug fever is treated quickly and properly. At high fever levels due to thermal regulation problems, the organism is irreversibly damaged. If the triggering preparation cannot be stopped immediately, the fever is lowered by antipyretic analgesics.

Suitable: paracetamol or aspirin -Präparate. However, it would be better to replace the triggering preparation with a drug from a different group of active substances. The more severe the crisis and the longer it lasts, the worse the healing rate. The mortality rate from anaphylactic shock is alarmingly high. The prognosis for Quincke’s edema can also be very poor if it is not recognized and treated immediately. The same applies to the rarely occurring hypersensitivity syndrome (HSS).


One of the most important preventive measures against drug fever is to inform the attending physician about all known intolerances and allergies. If there has already been an intolerance to certain medications, this must be reported. It is also important to make the attending physician aware of all medication that is taken regularly.

In this way, possible interactions with other preparations can be excluded or their effects can at least be observed. Reading and internalizing the instruction leaflet is an equally important measure. Here the patient is informed about known reactions to the prescribed medication and how often they occur. With this information armed, the patient can begin an attentive self-observation.

If any of the side effects and interactions mentioned apply to the patient, the doctor must be informed accordingly. Unauthorized discontinuation of the preparation due to drug fever is not permitted. The patient should also not refrain from taking the preparation without authorization due to the reactions described in the package insert.

If he has concerns about certain interactions or side effects, he should consult the practitioner again. It is important to react immediately to any unusual symptoms. If drug fever occurs, the doctor must be informed immediately.


Medicines serve to relieve symptoms and bring about recovery. However, sometimes complications such as drug fever arise. The aftercare aims to eliminate the typical side effects. Allergies and intolerances usually cause the increased temperature. In rare cases they reach dangerous proportions.

Doctors usually diagnose drug fever by taking a temperature reading. They also sometimes order a blood test. Research into the causes is also carried out as part of a conversation. If the suspicion is confirmed, the drug is immediately discontinued and, if necessary, replaced with another one. Sometimes fiber-lowering agents must be administered instead of discontinuation.

The doctor documents his diagnosis and informs the patient about which drugs he should avoid in the future. The person concerned accepts this fact in his knowledge. The extent to which a further scheduled examination is necessary depends on the intensity of the drug fever. In practice, there is usually no need for further follow-up care.

Patients can only counter the recurrence of drug fever by not taking certain medications. The substances involved are available on the basis of the initial diagnosis. In practice, the person concerned is obliged to cooperate. Before treatment, doctors usually ask whether there are any problems with medication. Here, potential dangers must be pointed out as a preventive measure.

You can do that yourself

Only in the case of a mild course of drug fever can the person concerned find remedial measures with their own measures. If you suspect that a certain drug triggered the fever, you should consult your doctor to be on the safe side.

At higher temperatures, trivializing the fever can be dangerous. A healthy lifestyle and diet as well as an intact immune system are good prerequisites for surviving a mild form of drug fever. People with previously damaged organs, an intestine contaminated with pathogenic germs or known allergies should try to monitor their symptoms as closely as possible and, if necessary, have them treated.

Permanent damage from years of alcoholism, drug addiction and other addictions can make a drug fever much more difficult – even if the addiction itself has already been defeated. It is helpful to aim for a generally healthy lifestyle.

Drug Fever

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