The effect of cost on adherence to prescription medications in Canada

I agree with Law et al(1) that cost of therapy is an important factor that may result in sub-optimal adherence to medical therapy. In addition, barriers to adherence are numerous including the treatment of asymptomatic conditions or risk factors, complex medical regimens, side effects, drug-drug interactions, poor understanding of the individual patient. To improve adherence to therapy, various modalities have been used in clinical practice including compliance packaging (also known as blister packs), that have their benefits(2) and limitations (Table). However, the major limitation being the increased cost of therapy, as the blister packs are often filled by the pharmacies at 2 to 4 week intervals (than every 90-days or every 3-months, when medications are prescribed in the containers), and each time the new blister pack is given to the patient, is considered as a refill and full dispensing fee is charged either to the patient or to the insurer. The dispensing cost associated with re-filling the blister packs is a major cost factor than the cost of the actual medication, especially for common conditions where the agents often are generic. For example, the cost of a single 90-day prescription of metformin is $21.48 ($10.99 for the cost of drug + $10.49 the dispensing fee), and if the same medication is filled monthly, the cost is over 2-times at $44.01 ($4.10 x3 = $12.54 for cost of the drug + $31.47 (3 times the dispensing fee of $10.49 each)), and if the same prescription is filled every 14 days, then the cost is 3.5 times higher at $75.72 ($12.78 for the cost of drug and $62.94 (6 times the dispensing fee of $10.49 each), with still short of 6-days supply. This cost of dispensing fee exponentiates as the number of therapeutic agents increase.

Physicians should consider the not only the actual cost of the medication(s) but also the dispensing fees charged to the patient when writing prescriptions and patients who are stable on therapy should be given at least 3-month supply to curtail the dispensing costs, especially when patients are on multiple agents. The Pharmacies should supply the prescribed duration of therapy, whether the medications are dispensed in bottles or in compliance packages, and must follow The Ontario Drug Interchangeability and Dispending Fee Act that states, “The medications used in the compliance aid are to be dispensed for the entire prescribed quantity, unless otherwise indicated by the patient or prescriber(3).” The pharmacists should be transparent with the patients of the indirect increased cumulative cost of the prescription, when the duration of refills is shortened.

Table: Advantages and disadvantages of compliance (blister or bubble) packing of medication(s)

Pros

• Improves adherence – improved outcomes

• Improves integrity of medications by improving shelf life and barrier against tempering

• May Prevent overdosing (accidental or intentional) – by weekly supplies

Cons:

• Higher Cost – 2 to 4 times prescription charges

• Difficult to Stagger medications

• Interaction with other agents – L-thyroxine and iron

• If there are changes – need to go back to pharmacy

• Time consuming

• PRN or as required medications are not suitable for such devices

• Storage temperature for different agents might be different

• May not be ‘child resistant’

Malvinder S. Parmar, MB, MS, FRCPC

References:

1. Law MR, Cheng L, Dhalla IA, Heard D, Morgan SG. The effect of cost on adherence to prescription medications in Canada. CMAJ. Feb 21 2012;184(3):297-302.
2. Lee JK, Grace KA, Taylor AJ. Effect of a pharmacy care program on medication adherence and persistence, blood pressure, and low-density lipoprotein cholesterol: a randomized controlled trial. JAMA. Dec 6 2006;296(21):2563-2571.
3. Drug Interchangeability and Dispensing Fee Act, R.S.O. 1990, c. P.23 Section 9.1. https://www.ontario.ca/laws/statute/90p23#BK9 (accessed 22 July 2019).