5 Common Drug-Drug interactions

5 Common

 Drug-Drug interactions  

Fluoxetine / Phenelzine

·    Fluoxetine: Selective Serotonin Reuptake Inhibitors (SSRI).

·    Phenelzine: Monoamine Oxidase Inhibitors (MAOI)

·    Interaction: SSRI will enhance the serotonergic effect of MAOI

·    Consequence: Serotonin syndrome (mental status changes, agitation, tachycardia, or even fetal outcome)

·    Common side effects:

1.  Chills

2. cold sweats

3. confusion

4. dizziness, faintness, or lightheadedness when getting up from a lying or sitting position

5. shakiness in the legs, arms, hands, or feet

6. sudden jerky movements of the body

7. swelling

Spironolactone / KCI

·    Spironolactone: Potassium-Sparing Diuretics

·    Interaction: Using both drugs together will increase the potassium level within the patient's body

·    Consequence: Cause hyperkalaemia (muscular weakness, fatigue, arrhythmias, bradycardia)

·     Common side effects:

1. bloody or black, tarry stools

2. bloody urine

3. confusion

4. constipation

5. cough

6. dizziness

7. dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

Warfarin / NSAID

·    Warfarin: Anticoagulant, which increase bleeding risk

·    NSAID: Will increase risk of Gl bleeding

·    Interaction: NSAID may enhance the anticoagulation effect of Warfarin

·    Consequence: Risk of serious GI bleeding, or even fatal haemorrhaging.

·    Consideration: Use Paracetamol as analgesic while on Warfarin.

·    Common side effects:

1. blood in the urine
2. bloody stools
3. blurred vision
4. stomach pain with cramping
5. sweating

Pimozide / Ritonavir

·    Pimozide: can cause prolong the QT interval, and lead to arrhythmias

·    Ritonavir: Strong CYP3A4 inhibitor

·    Interaction: Ritonavir will block the metabolism of Pimozide, leading to increase serum concentration

·    Consequence: Fatal arrhythmia; absolute contraindication for this combination

·    Common side effects:

1. nausea, vomiting, stomach pain, diarrhea

2. numbness or tingling in your hands or feet or around your mouth

3. feeling weak or tired

4. rash

5. changes in the shape or location of body fat (especially in your arms, legs, face, neck, breasts, and waist).

Digoxin / Quinidine

·    Digoxin: Cardiac glycoside.

·    Quinidine: Class 1a antiarrhythmics.

·    Interaction: Quinidine lead to a decreased volume of distribution of digoxin, and increasing its serum concentration.

·    Consequence: Digoxin toxicity (dizziness, confusion, delirium, vision disturbance, cardiac disturbances).

·    Common side effects:

1. Diarrhea, dizziness, headache.
2. skin rash
3. hives
4. itching
5. swelling of your face, lips, or tongue
6. trouble breathing