DrugLib.com — Drug Information Portal

Rx drug information, pharmaceutical research, clinical trials, news, and more

Tolterodine Extended Release (Tolterodine Tartrate) - Drug Interactions, Contraindications, Overdosage, etc

 
 



DRUG INTERACTIONS

Potent CYP2D6 Inhibitors

Fluoxetine, a potent inhibitor of CYP2D6 activity, significantly inhibited the metabolism of tolterodine immediate-release in CYP2D6 extensive metabolizers, resulting in a 4.8-fold increase in tolterodine AUC. There was a 52% decrease in Cmax and a 20% decrease in AUC of 5-hydroxymethyl tolterodine (5-HMT), the pharmacologically active metabolite of tolterodine [see CLINICAL PHARMACOLOGY ]. The sums of unbound serum concentrations of tolterodine and 5-HMT are only 25% higher during the interaction. No dose adjustment is required when tolterodine and fluoxetine are co-administered [see CLINICAL PHARMACOLOGY ].

Potent CYP3A4 Inhibitors

Ketoconazole (200 mg daily), a potent CYP3A4 inhibitor, increased the mean Cmax and AUC of tolterodine by 2- and 2.5-fold, respectively, in CYP2D6 poor metabolizers.

For patients receiving ketoconazole or other potent CYP3A4 inhibitors such as itraconazole, clarithromycin, or ritonavir, the recommended dose of tolterodine tartrate extended-release capsules is 2 mg once daily [see DOSAGE AND ADMINISTRATION and CLINICAL PHARMACOLOGY ].

Other Interactions

No clinically relevant interactions have been observed when tolterodine was co-administered with warfarin, with a combined oral contraceptive drug containing ethinyl estradiol and levonorgestrel, or with diuretics [see CLINICAL PHARMACOLOGY ]

Other Drugs Metabolized by Cytochrome P450 Isoenzymes

In vivo drug-interaction data show that tolterodine immediate-release does not result in clinically relevant inhibition of CYP1A2, 2D6, 2C9, 2C19, or 3A4 as evidenced by lack of influence on the marker drugs caffeine, debrisoquine, S-warfarin, and omeprazole [see CLINICAL PHARMACOLOGY ].

Drug-Laboratory-Test Interactions

Interactions between tolterodine and laboratory tests have not been studied.

Other Anticholinergics

The concomitant use of tolterodine tartrate extended-release capsules with other anticholinergic (antimuscarinic) agents may increase the frequency and/or severity of dry mouth, constipation, blurred vision, somnolence, and other anticholinergic pharmacological effects.

OVERDOSAGE

Overdosage with tolterodine tartrate extended-release capsules can potentially result in severe central anticholinergic effects and should be treated accordingly.

ECG monitoring is recommended in the event of overdosage. In dogs, changes in the QT interval (slight prolongation of 10% to 20%) were observed at a suprapharmacologic dose of 4.5 mg/kg, which is about 68 times higher than the recommended human dose. In clinical trials of normal volunteers and patients, QT interval prolongation was observed with tolterodine immediate-release at doses up to 8 mg (4 mg bid) and higher doses were not evaluated [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY ].

A 27-month-old child who ingested 5 to 7 tolterodine immediate-release 2 mg tablets was treated with a suspension of activated charcoal and was hospitalized overnight with symptoms of dry mouth. The child fully recovered.

CONTRAINDICATIONS

Tolterodine tartrate extended-release capsules are contraindicated in patients with urinary retention, gastric retention, or uncontrolled narrow-angle glaucoma. Tolterodine tartrate extended-release capsules are also contraindicated in patients with known hypersensitivity to the drug or its ingredients, or to fesoterodine fumarate extended-release tablets which, like tolterodine tartrate extended-release capsules, are metabolized to 5-hydroxymethyl tolterodine [see WARNINGS AND PRECAUTIONS (5.2) , ].

-- advertisement -- The American Red Cross
 
Home | About Us | Contact Us | Site usage policy | Privacy policy

All Rights reserved - Copyright DrugLib.com, 2006-2017