SPC changes
Detrusitol
The summaries of product characteristics for Detrusitol and Detrusitol
XL (tolterodine; Pfizer) have been updated to include new warnings regarding
QT prolongation. They now state that tolterodine should be used with
caution in patients with risk factors for QT prolongation, including
congenital or documented acquired QT prolongation, electrolyte disturbances
(such as hypokalaemia, hypomagnesaemia and hypocalcaemia), bradycardia,
relevant pre-existing cardiac diseases (ie, cardiomyopathy, myocardial
ischaemia, arrhythmia, congestive heart failure), concomitant administration
of drugs known to prolong QT-interval including Class IA (eg, quinidine,
procainamide) and Class III (eg, amiodarone, sotalol) anti-arrhythmics.
They add that this holds especially true when taking potent CYP3A4 inhibitors
and that concomitant treatment with these should be avoided. The SPCs
also state that an increase in QT interval was observed at a total daily
dose of 8mg immediate release tolterodine (twice the recommended daily
dose of the immediate release formulation and equivalent to three times
the peak exposure of the prolonged release capsule formulation) administered
over four days. In the event of tolterodine overdose, standard supportive
measures for managing QT prolongation should be adopted. See SPCs.
Distamine
The summary of product characteristics for Distamine (D-penicillamine;
Alliance) has been updated. The SPC now states that there have been
several cases of reversible cutis laxa in infants born to mothers taking
penicillamine throughout pregnancy. It adds that there are also anecdotal
reports both of congenital abnormalities and of successful outcomes
in patients who have remained on penicillamine during pregnancy. It
recommends that if treatment is to be continued following a risk-benefit
analysis, consideration should be given to reducing the dose of penicillamine
to the lowest effective dose. In the undesirable effects section, it
states that deterioration of the neurological symptoms of Wilson’s
disease have been reported. Glomerulonephritis, pulmonary haemorrhage
and Goodpasture’s syndrome have also been added as “other
complications”. See SPC.
Truvada
The summary of product characteristics for Truvada (emtricitabine,
tenofovir; Gilead) now states that acute tubular necrosis is a very
rare, rather
than a rare, undesirable effect. Nephritis and nephrogenic diabetes
have also been added to the undesirable effects section. In addition,
the
SPC states that co-administration of tenofovir and didanosine is not
recommended. See SPC.
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