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en:manuals:freemedforms:drugs:drugdruginteractions

Test DDIs (Drug Drug Interactions)

Severity, definitions of DDI alerts

  • Severe Association is contraindicated. Avoid combination. Alert shouldn't be bypassed. The interaction between these medications may be life-threatening or may cause permanent damage. Medical intervention may be required.
  • Moderate Usually avoid combination. Combination may result in the potential deterioration of the patient's condition. The patient should be monitored for the possible manifestations of the interaction. Medical intervention or a change in therapy may be required.
  • Minor Clinical effects of the interaction are limited and may be bothersome but would not usually require a major change to therapy. The patient should be monitored for the possible manifestations of the interaction.
  • Caution The interaction may occur based on the mechanism of action of the co-administered medicines. Be alert for increased or decreased effect, depending on the combination of medicines.
Icon Meaning
Drug not recognized by FreeRx (interactions cannot be calculated) Drug not recognized by FreeRx (interactions cannot be calculated)
Known drug, no interaction Known drug, no interaction
INN already present: therapeutic duplication INN already present: therapeutic duplication
Caution Caution
Minor DDI Minor DDI
Moderate DDI Moderate DDI
Severe DDI Severe DDI
Textual prescription: cannot evaluate interaction Textual prescription: cannot evaluate interaction
Icon Meaning
Icon representing cytochrome P450Drug interaction due to cytochrome P450
Icon representing P-glycoproteinDrug interactions due to P-glycoprotein

Extra information about interaction

  • Type of interaction:
    • synergistic effect: increase side effects or toxicity (additive pharmacodynamics)
    • antogonist effect: interaction causes a decrease in the effects of one or both of the drugs
    • mechanism of action when it is known
  • severity
  • management Minor DDIs require simple measures to be avoided such as a reduction of the dosage or measurement of blood level of the drugs. Caution alert: the interaction may occur based on the mechanism of action of the co-administered medicines. Be alert for increased or decreased effect, depending on the combination of medicines.

Calculation of DDI

  • Interaction engine uses ATC codes linked to the active ingredients of drugs. These ATC codes are grouped into “DDI prone therapeutical classes” (as defined by ANSM in the french DDI knowledge base)
  • 1 INN may belong to multiple classes
  • INN and classes appear in a tooltip if you immobilize the arrow of the mouse over the name of the drug for a few seconds
You can add drugs only to test for DDI: these added drugs will not be printed on the prescription. Use this feature to test for DDIs between long term treatment and acute treatment.
BEWARE of unrecognized drugs. If the drug is not recognized by FreeRx, you should check DDIs with another method.
en/manuals/freemedforms/drugs/drugdruginteractions.txt · Last modified: 2014/11/20 22:45 (external edit)