Drug Criteria & Outcomes-Field narrows as on-line pharmacy giants merge
Drug Criteria & Outcomes-Field narrows as on-line pharmacy giants merge
PBMs make exclusive deals with on-line suppliers
The nation's third largest pharmacy benefit manager (PBM), Express Scripts Inc., the owner of its own on-line pharmacy, yourPharmacy.com, has agreed to purchase 19% of the on-line pharmacy PlanetRx.com in exchange for a five-year deal to be the exclusive supplier to PlanetRx.com.
As part of the deal, yourPharmacy.com will disappear from the marketplace to make way for the co-owned PlanetRx.com. PlanetRx.com now will become the exclusive supplier to some 36 million Express Scripts members.
In another merger, PCS, the nation's second-largest PBM, which is owned by RiteAid, also has set up an exclusive supplier deal by way of RiteAid's purchase of 25% of the on-line pharmacy drugstore.com.
The first on-line pharmacy to emerge earlier this year, Soma.com, has since been purchased by CVS.
Regulators lagging behind
In the meantime, government and national pharmacy organizations continue to try to play oversight catch-up to the ever-growing on-line pharmacy industry.
This summer, a hearing was held by the oversight subcommittee of the House Committee on Commerce, which was attended by repre senta tives of the U.S. Food and Drug Admin istra tion, Federal Trade Commission, Justice Department, National Association of Boards of Pharmacy, and several Internet pharmacy representatives.
The hearing was aimed at focusing on ways to regulate the industry, specifically sites that would be considered illegal based on a lack of prescription control, faulty drug claims, and sales of unapproved drugs.
No concrete action was taken at the hearing. Instead, several overall topics to pursue were agreed upon, which included pursuing proposals on the disclosure of World Wide Web site operators, a determination of whether state or federal guidelines should be adopted, and defining proper doctor-patient relationships when prescriptions are filled on-line among other topics.
Significant Drug-Drug Interactions with Cisapride (Propulsid) | ||
Precipitant Drug | Object Drug | Description |
Anticholinergics/Antispasmodics atropine, belladonna, benztropine, dicyclomine, homatropine, hyoscyamine, oxybutynin, procyclidine, scopolamine, trihexyphenidyl | cisapride | Concurrent use expected to compromise beneficial effects of cisapride. |
Antiarrythmics, Class 1A (disopyramide, procainamide, quinidine); Class III (amiodarone, bretylium, ibutilide, sotalol) | cisapride | Known to prolong the QT interval as seen in arrhythmias. May result in torsades de pointes. Concomitant use with cisapride contraindicated. |
Antidepressants (tricyclics, nefazodone, maprotiline, fluvoxamine) | cisapride | Known to prolong the QT interval. May result in torsades de pointes. Concomitant use with cisapride contraindicated. |
Antipsychotics (phenothiazines, perphenazine, amitriptyline) | cisapride | Known to prolong the QT interval. May result in torsades de pointes. Concomitant use with cisapride contraindicated. |
Azole antifungals (fluconazole, itraconazole, ketoconazole, iconazole) | cisapride | Known to prolong QT interval. Concomitant use with cisapride contraindicated. |
Bepridil | cisapride | Known to prolong QT interval. Concomitant use with cisapride contraindicated. |
Macrolides (azithromycin, clarithromycin, erythromycin, troleandomycin) | cisapride | Known to prolong QT interval. Concomitant use with cisapride contraindicated. |
Protease Inhibitors (emprenavir, indinavir, nelfinavir, ritonavir, saquinavir) | cisapride | Known to prolong QT interval. Concomitant use with cisapride contraindicated. |
Grepafloxacin, sparfloxacin | cisapride | Known to prolong QT interval. Concomitant use with cisapride contraindicated. |
H2 antagonists (cimetidine) | cisaprid | Increased peak plasma level and AUC of cisapride may occur; other H2 antagonists have no effect on cisapride absorption. |
Cisapride | H2 antagonists | GI absorption of cimetidine and ranitidine is accelerated by cisapride. |
Cisapride | Anticoagulants (anisindione, coumarin, wafarin) | Since coagulation times (PT/INR) may be increased, it is advisable to check them within first few days after start and D/C of cisapride therapy. Adjust anticoagulant dose as necessary. |
Cisapride | cyclosporine | Cisapride has been shown to increase peak concentrations and AUC and decrease time to peak concentration of cyclosporine. Possible mechanism is increased rate of absorption of cyclosporine. Monitor cyclosporine levels and toxicities regularly. |
Cisapride | tacrolimus | Both agents are metabolized by the CYP 450 3A4 system, which may result in competitive inhibition and may produce higher plasma concentrations of one or both agents. Monitor tacrolimus plasma concentrations and look for signs of tacrolimus toxicity (i.e. nephrotoxicity, hyperglycemia, hyperkalemia). Doses of tacrolimus may need to be reduced with concurrent use. |
Delavirdine | cisapride | Known to prolong the QT interval. Concomitant use should be avoided. |
Diltiazem | cisapride | Diltiazem is a known CYP 450 3A4 inhibitor, and cisapride is a 3A4 substrate. Concomitant administration should be avoided due to possible QT interval prolongation and arrhythmias. |
Dolestron | cisapaide | Both agents can prolong the QT interval and result in arrhythmias. Concomitant use should be avoided or cardiac function should be closely monitored. |
Efavirenz | cisapride | Both agents metabolized by CYP 450 3A4 system. Competition for this pathway could result in inhibition of cisparide metabolism, creating the potential for prolongation of the QT interval and arrhythmias. Concomitant use is not recommended. |
Editor's note: The heartburn medication cisapride (Propulsid, Janssen Pharmaceutica) was the subject of FDA warning letters in 1996 and 1998 based on reports of serious adverse and events and up to 38 patient deaths associated with the drug. The FDA warnings included a range of drug-drug interactions to avoid and the avoidance of use of the drug with various patient cardiovascular disorders. This is a chart of drug classes warranting caution with the use of cisapride. | ||
Source: Scott & White Memorial Hospital, Department of Pharmacy Services, Temple, TX. |
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