Physical access refers to the availability of stocks of drugs normally present in a pharmacy (and hence authorized for distribution at that pharmacy). In many developing countries, depletion of drug inventory threatens the continuity of care and the usefulness of the health services.

Table 9. Number of localities with a health service having a pharmacy (example)

Table 10. Average availability of two drugs at health centres in Rwanda

Source: Habiyambere (15)

* Centres in public sector B participate in a drugs supply programme not available to the other sectors

In order to prevent shortages of stock, the duration of these shortages must first be measured. Shortages of stock may be measured in terms of the proportion of days (or weeks) that drugs are not on the shelves during the period considered (a month or a year). Table 10 provides an example. One must first know what drugs are supposed to be available. Then, stock management records or spot checks permit calculation of the number of days that certain drugs are out of stock during a given month. Without this information it is not possible to know whether reorganization has reduced stock shortages. Progress needs to be monitored very closely.

When information is plentiful, stock shortages that are calculated for individual drugs can be grouped to derive figures for classes of drugs. The mean duration of shortages of all vital, essential or non-essential drugs in terms of the VEN classification can be calculated.