Operational Guide for National Tuberculosis Control Programmes on the Introduction and Use of Fixed-Dose Combination Drugs: Annex 5. Steps in the quantification of anti-TB drugs using consumption-based information

Operational Guide for National Tuberculosis Control Programmes on the Introduction and Use of Fixed-Dose Combination Drugs
(2002; 81 pages)

Table of Contents

ACKNOWLEDGEMENTS
LIST OF ACRONYMS AND ABBREVIATIONS
PREFACE
KEY POINTS
1. INTRODUCTION
	1.1 Aim and objectives
	1.2 What you can find in this guide
	1.3 Background and rationale
2. PROGRAMMATIC AND MANAGERIAL REQUIREMENTS FOR FDCS
	2.1 DOTS strategy
		2.1.1 Challenges in TB control
		2.1.2 Why switch to FDCs?
		2.1.3 FDCs and adverse effects
		2.1.4 Directly observed treatment and FDCs
	2.2 FDC formulations in the WHO Model List of Essential Medicines
	2.3 Treatment regimens using FDCs
	2.4 Justification for dosage forms and dosage schedules
3. FDC DRUG MANAGEMENT
	3.1 Product selection
	3.2 Procurement
		3.2.1 Quantification of drug needs
		3.2.2 Procurement methods and selection of suppliers
		3.2.3 Procurement and quality assurance
		3.2.4 Minimum product specifications, packaging and labelling requirements to be specified in the contract
	3.3 Distribution and storage
	3.4 Rational use of anti-TB medicines
	3.5 Drug problem reporting system
	3.6 Monitoring and evaluation
	3.7 Summary checklist for good anti-TB drug management
4. ENSURING THE QUALITY OF FDC DRUGS
	4.1 Building a quality assurance system for the national TB programme
		4.1.1 Quality assurance where there is an operational drug regulatory authority
		4.1.2 Quality assurance where there is no national drug regulatory authority or no operational drug registration system
	4.2 Bio-availability and bio-equivalence (interchangeability) data
	4.3 Laboratory testing
	4.4 The WHO Certification Scheme
	4.5 Facilitating the drug registration process
5. HOW TO INTRODUCE AND CHANGE OVER TO A REGIMEN WITH 4-DRUG FDCS/2-DRUG FDCS: PLANNING AND IMPLEMENTING A "SCENARIO"
	5.1 The challenge
	5.2 Planning
	5.3 The process
		5.3.1 Decision-making phase
		5.3.2 Preparation
		5.3.3 Initial implementation
		5.3.4 Full implementation
Annex 1. Glossary and use of terms
Annex 2. WHO Certification Scheme - Model Certificate of a Pharmaceutical Product¹
Annex 3. WHO Certification Scheme - Model Batch Certificate of a Pharmaceutical Product
Annex 4. Example of an order form for anti-TB drugs for treatment facilities
Annex 5. Steps in the quantification of anti-TB drugs using consumption-based information
Annex 6. Suggested reading
Request for feedback on the guide

Annex 5. Steps in the quantification of anti-TB drugs using consumption-based information

The consumption method uses data on drug consumption. The reliability of this method depends on a well-established and stable supply system with a relatively uninterrupted supply and full supply pipeline. Consumption data may or may not reflect rational prescribing and use of drugs. In this method, a list of anti-TB drugs is prepared using the most accurate inventory records of past consumption. Care should be taken that drug stock-outs and numbers of identified cases not treated are included in the consumption data. The following are the steps in quantifying anti-TB drugs using the consumption-based method:

1. Prepare a list of anti-TB drugs to be quantified.

2. Determine the period of time to be reviewed for consumption. If the procurement/order is to cover a 12-month period, consumption data for the past 12 months should be reviewed.

3. Enter consumption data for each drug, including total quantity used during the review period, number of days that each drug was out of stock in the review period, and the average lead time for the last several procurements.

4. Calculate the average monthly consumption which is the key variable in the quantification formula and should be as accurate as possible.

5. Calculate the safety/reserve/buffer stock needed for each drug.

6. Calculate the quantity of each drug required in the next purchasing period.

7. Adjust for expected changes in consumption pattern.

8. Adjust for losses.

9. Record the number of drugs currently in stock.

10. Record the number of drugs already on order but not yet received.

11. Compile decentralized quantifications i.e. at each facility or storage point.

12. Estimate costs for each drug and total costs.

13. Compare total costs with the budget and make adjustments.

Formula:

Average monthly consumption, adjusted for stock-outs (C_A) = C_T ÷ [R_M - (D_OS ÷ 30.4)]

Basic safety/reserve stock (B_S) = C_A x L_T

Quantity to order (Q_O) = C_A x (L_T + P_P) + S_S - (S₁ + S_O)

Where	C_A = Average monthly consumption, adjusted for stock-outs.
	C_T = Total consumption during review period, in basic units e.g. tablets.
	D_OS = Number of days an item was out of stock during the review period.
	L_T = Average lead time in months.
	P_P = Procurement period (number of months to be covered by order).
	Q_O = Quantity to order in basic units, before adjustment for losses or programme change.
	R_M = Review period in months (number of months of data reviewed for forecasting).
	S_O = Stock currently on order but not yet received, in basic units.
	S₁ = Stock currently in inventory, in basic units.
	S_S = Quantity needed for safety/reserve stock.
	30.4 = Average number of days per month.