Carisoprodolol Quantity Limit Policy Impact Analysis Carisoprodolol (Soma ) is a skeletal muscle relaxant that has deemed by many to have limited effectiveness for the treatment of acute musculoskeletal conditions and no proven effectiveness for pain. Also, carisoprodolol has a considerable abuse potential, and cases of dependence, abuse, and non-medical use are becoming increasingly common. While rarely fatal in overdose, carisoprodolol exacerbates toxicity occurring with other CNS depressants. A previous review of fee-for-service patient utilization indicate that 11% of all carisoprodolol users averaged over the recommended daily dose (14 mg 3 tablets), 65% have received more than 6 tablets per 3 days, and 3% received more than 27 tablets per 3 days. Because of the documented lack of efficacy and notable potential for abuse, other health care systems have completely removed carisoprodolol from the formulary. Effective 11/15/2, on the recommendations of the Oregon DUR board, OMAP implemented a prior authorization policy for carisoprodolol and carisoprodolol combination products for quantities exceeding 56 tablets in 9 days. The goals of this analysis were to evaluate the impact of this policy not only on the utilization of carisoprodolol, but also potentially substitutable agents (e.g. alternate musculoskeletal relaxants, benzodiazepine), and use of medical services. Evaluation Methods Pharmacy and medical claims were analyzed from longitudinally from January 22 to September 23. The following outcomes were evaluated: 1. Count of musculoskeletal (MS) relaxant and benzodiazepine prescriptions PMPM 2. Sum of dispensed quantities for MS relaxants 3. Average monthly daily dose and quantity dispensed/rx dispensed 4. Monthly cost for MS relaxants projected compared to actual 5. Sum quantity, Rx count, and costs for MS relaxants among carisoprodolol users 6. Count of office visits, ER encounters, and hospitalizations among carisoprodolol users All analysis used cost reflecting the ingredient costs with copays added back. The medically needy population was excluded from the analysis to control for their elimination from the OHP in 23. Results As shown in figure 1, the volume of prescriptions for carisoprodolol decreased markedly after the quantity limit PA was implemented on 11/2. Before the PA, the average number of carisoprodolol prescriptions dispensed per 1 members before the PA was 7.7 compared to 2.3 after the PA. A similar trend, shown in figure 2, was observed when the sum of quantities dispensed for carisoprodolol was examined. In the general population, no appreciable increase in the use of any other muscle skeletal relaxant was observed. Similarly, figure 2 shows the sharp decrease in the sum of dispensed quantities for carisoprodolol per 1 members before and after the PA was implemented. Figure 4 depicts the computed average daily dose (mg) for carisoprodolol prescriptions. A noticeable decline in the average daily dose was observed from 111 mg QD before the PA to 956 mg QD after the PA (table 1). As expected, table 2 shows average number of tablets dispensed per prescription declined from 63 to 4. Carisoprodolol costs on a per member per month (PMPM) basis were reduced markedly after the PA was implemented. Figure 4 shows the actual costs PMPM compared the projected based on the 6 month trend prior to the PA. Our projections indicate the PA saved $.93 PMPM, or approximately $16, in total per month. When the cost of the PA is factored in, the total monthly savings attributable to the PA is estimated to be $15,794. Within the specified time period 3,562 unique patients had at least one carisoprodolol prescription. Figures 5 thru7 show trend analysis for total prescriptions dispensed, sum of dispensed quantities, and total cost among these 3,562 carisoprodolol users. Upon visual inspection of these trend analyses, increases in cyclobenzaprine and methocarbamol corresponding with the PA implementation date can be observed. We also examined utilization patterns of benzodiazepines among carisoprodolol users. Figure 8 shows, that notable changes in benzodiazepine utilization were observed among carisoprodolol users after the PA was implemented. Figure 9 shows medical service claims for carisoprodolol users before and after the PA was activated. No notable increase or decrease in the rate of emergency room services, hospitalizations, or office visits was observed among carisoprodolol users.
Figure 1: Rx Count/1 Member/Month 16 14 12 1 8 6 4 2 Sep-3 Aug-3 Jul-3 Jun-3 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 CYCLOBENZAPRINE HCL BACLOFEN CARISOPRODOL METHOCARBAMOL SKELAXIN TIZANIDINE HCL ZANAFLEX CHLORZOXAZONE ORPHENADRINE CITRATE DANTRIUM SOMA FLEXERIL CARISOPRODOL COMPOUND LIORESAL INTRATHECAL ORPHENADRINE COMPOUND BOTOX NORFLEX ORPHENADRINE COMPOUND FORTE ROBAXIN-75 ROBOMOL 5 NORGESIC ROBOMOL-75 ORPHENGESIC FORTE ORPHENGESIC MYOBLOC ROBAXIN NORGESIC FORTE LIORESAL ROBAXISAL
Figure 2: Sum of quantities dispensed/1 members/month 7 6 5 4 3 2 1 Sep-3 Aug-3 Jul-3 Jun-3 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 CYCLOBENZAPRINE HCL BACLOFEN CARISOPRODOL METHOCARBAMOL SKELAXIN TIZANIDINE HCL ZANAFLEX DANTRIUM CHLORZOXAZONE ORPHENADRINE CITRATE SOMA FLEXERIL ORPHENADRINE COMPOUND CARISOPRODOL COMPOUND NORFLEX ROBAXIN-75 NORGESIC ROBOMOL 5 ORPHENADRINE COMPOUND FORTE ROBOMOL-75 ORPHENGESIC FORTE ORPHENGESIC ROBAXIN LIORESAL LIORESAL INTRATHECAL ROBAXISAL NORGESIC FORTE BOTOX MYOBLOC
Figure 3: Average daily dose 14 12 1 8 6 4 2 Jun-3 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 Table 1: Average Daily Dose Average Daily Dose (mg) Pre (1/2 11/2) 119.915 63.13 Post (12/2 6/3) 956.173 39.54 Average Quantity Dispensed/Rx
Figure 4: Cost PMPM $.2 $.18 $.16 $.14 $.12 $.1 $.8 $.6 $.4 $.2 $. Jan-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Dec-2 Nov-2 Oct-2 Sep-2 Jan-3 Sep-3 Aug-3 Jul-3 Jun-3 May-3 Apr-3 Mar-3 Feb-3 $pmpm PROJECTION Table 2: Cost Savings Projections Month 12/2 1/3 2/3 3/3 4/3 5/3 6/3 7/3 8/3 9/3 Average Actual PMPM.61.24.16.17.18.15.18.18.16.18.22 Projected PMPM*.139.1273.1237.121.1165.1129.193.157.121.985.115 Difference.7.13.18.13.98.98.91.88.87.8.93 Utilization Savings $11,453 $16,39 $16,913 $19,8 $18,529 $17,341 $16,174 $15,727 $14,879 $12,872 $16, PA Costs - - $736 $836 $786 $447 $647 $972 $88 $575 $735 Total Savings $16,177 $18,964 $17,743 $16,894 $15,527 $14,755 $13,999 $12,297 $15,794 *Trend based on 6 months prior to implementation date
Figure 5: 25 2 15 1 5 Count of Rx dispensed for muscle relaxants among carisoprodolol users Sep-3 Aug-3 Jul-3 Jun-3 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 CYCLOBENZAPRINE HCL METHOCARBAMOL BACLOFEN SKELAXIN TIZANIDINE HCL ZANAFLEX CHLORZOXAZONE ORPHENADRINE CITRATE DANTRIUM FLEXERIL Figure 6: Sum of quantities dispensed for muscle relaxants among carisoprodolol users 14 12 1 8 6 4 2 Sep-3 Aug-3 Jul-3 Jun-3 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 CYCLOBENZAPRINE HCL METHOCARBAMOL BACLOFEN SKELAXIN TIZANIDINE HCL ZANAFLEX CHLORZOXAZONE DANTRIUM ORPHENADRINE CITRATE FLEXERIL
Figure 7: Cost among carisoprodolol users $8, $7, $6, $5, $4, $3, $2, $1, $ Sep-3 Aug-3 Jul-3 Jun-3 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 SKELAXIN TIZANIDINE HCL ZANAFLEX METHOCARBAMOL BACLOFEN CYCLOBENZAPRINE HCL DANTRIUM ORPHENADRINE CITRATE CHLORZOXAZONE
Figure 8: Count of benzodiazepine claims among carisoprodolol users 35 3 25 2 15 1 5 Jun-3 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 ALPRAZOLAM DIAZEPAM LORAZEPAM TEMAZEPAM CHLORDIAZEPOXIDE HCL FLURAZEPAM HCL CLORAZEPATE DIPOTASSIUM OXAZEPAM TRIAZOLAM Figure 9: Count of medical claim types among carisoprodolol users 7 6 5 4 3 2 1 7 6 5 4 3 2 1 May-3 Apr-3 Mar-3 Feb-3 Jan-3 Dec-2 Nov-2 Oct-2 Sep-2 Aug-2 Jul-2 Jun-2 May-2 Apr-2 Mar-2 Feb-2 Jan-2 *Office visits on right axis ER HOSP OFFICE VISITS