Self Directed Learning 4.2: Drug Interactions
Case Scenario 1
Question
What further
background
information do
you need to
clarify the
question and
minimise the
risks when
advising the
caller?
I have just been prescribed some medicine for my stomach discomfort. I
use antacids to help with the symptoms after meals. Can I continue to use
the antacid?
PERSON
MEDICINES
Who is asking?
45yr old male about himself
Medicines (name, dose, freq)?
Lansoprazole 15mg once daily
Peptac® liquid 20mls four times a
day after meals and at bedtime
New or worsening symptoms?
Gastric discomfort after meals
Why asking?
Any allergies/medical conditions
Just prescribed the lansoprazole to
GORD – gastric-oesophageal reflux use in addition to his antacids. PIL
disease
says to speak to his GP if also taking
antacids.
Gather the further background information BEFORE searching for information.
What information
sources would
you use?
MedicinesChest:
No listing for Peptac®
eBNF:
Peptac® Suspension, sugar-free, sodium bicarbonate 133.5 mg, sodium
alginate 250 mg, calcium carbonate 80 mg/5 mL. Dose: 10–20 mL after
meals and at bedtime.
Interaction search: Antacids possibly reduce the absorption of lansoprazole.
eMC – PIL: Zoton FasTab®
In particular tell your doctor if you are taking medicines containing any of the
following active substances as Zoton FasTab® may affect the way these
drugs work:
List of drugs includes:
 antacids (used to treat heartburn or acid regurgitation)
eMC – SPC: Zoton FasTab®
Sucralfate/Antacids may decrease the bioavailability of lansoprazole.
Therefore lansoprazole should be taken at least 1 hour after taking these
drugs.
NetDoctor:
Food, antacids and sucralfate decrease the absorption of this medicine from
the gut and may make it less effective. For this reason, lansoprazole is best
taken on an empty stomach. Antacids and sucralfate should not be taken
within an hour of taking lansoprazole.
What advice
would you give?
Or would you
refer?
There is a possibility that the antacid may reduce the absorption of the
lansoprazole.
Advise the patient that they should take the lansoprazole anyway on an
empty stomach, i.e. 30 minutes before food. Advise the patient to take their
lansoprazole once they have got up in the morning, then to have their
breakfast (30 minutes later), then to have the first dose of Peptac® liquid at
least 30 minutes after breakfast.
Role Preparation for Nurse Advisors: Handling Medicines Calls
September 2007 v1.0
Self Directed Learning 4.2: Drug Interactions
Case Scenario 2
Question
What further
background
information do
you need to
clarify the
question and
minimise the
risks when
advising the
caller?
My dentist has prescribed miconazole gel. Is it ok with my other medicines?
PERSON
MEDICINES
Who is asking?
61yr old female about herself
Medicines (name, dose, freq)?
Warfarin 3mg once daily
Miconazole Oromucosal Gel after
meals four times a day
Aerobec 100 Autohaler® one puff
four times a day
Salbutamol inhaler 2 puffs four times
a day
New or worsening symptoms?
Sore mouth and tongue
Any allergies/medical conditions?
DVT three months ago. Asthmatic
Why asking?
Dentist has just prescribed the gel
after diagnosing oral thrush.
Gather the further background information BEFORE searching for information.
What information
sources would
you use?
eBNF:
Acute pseudomembranous candidiasis (thrush) is usually an acute infection
but it may persist for months in patients receiving inhaled corticosteroids,
cytotoxics or broad-spectrum antibacterials. When thrush is associated with
corticosteroid inhalers, rinsing the mouth with water (or cleaning a child’s
teeth) immediately after using the inhaler may avoid the problem. Treatment
with nystatin, amphotericin, or miconazole may be needed.
Interaction search: miconazole enhances anticoagulant effect of coumarins
(miconazole oral gel and possibly vaginal formulations absorbed)
eMC – SPC: Daktarin® Oral Gel
Drugs whose plasma levels effects or side effects should be monitored.
Their dosage, if co-administered with miconazole, should be reduced if
necessary.
List of drugs includes
oral anticoagulants,
eMC – PIL: Daktarin® Oral Gel
Combination with some other medicines may require a dose change for
either Daktarin® Oral Gel or the other medicine. Examples are:
blood thinning agents taken by mouth (anticoagulants, eg warfarin)
NetDoctor - Daktarin® Oral Gel
This medicine increases the anti-blood-clotting effect of anticoagulant
medicines such as warfarin, nicoumalone and phenindione. As this may
increase the risk of bleeding, your doctor may want to monitor your blood
clotting time (prothrombin time or INR) during and after a course of this
medicine, and may need to alter the dose of your anticoagulant as a result.
Role Preparation for Nurse Advisors: Handling Medicines Calls
September 2007 v1.0
What advice
would you give?
Or would you
refer?
The interaction between miconazole and warfarin is well documented and
clinically significant.
Advice the patient not to use the miconazole gel but to go back to the dentist
for an alternative. She should be advised to wash her mouth out with water
or brush her teeth after using her corticosteroid inhaler; this may prevent the
thrush occurring.
Role Preparation for Nurse Advisors: Handling Medicines Calls
September 2007 v1.0