The most common form of patient-controlled analgesia is self-administration of oral over-the-counter or prescription painkillers.

The inability of an obtunded patient to push the button is also considered an inherent safety feature of PCA.

[5] In 1968, Robert Wexler of Abbott Laboratories developed the Analgizer, a disposable inhaler that allowed the self-administration of methoxyflurane vapor in air for analgesia.

The device contained a rolled wick of polypropylene felt which held 15 milliliters of methoxyflurane.

Because of the simplicity of the Analgizer and the pharmacological characteristics of methoxyflurane, it was easy for patients to self-administer the drug and rapidly achieve a level of conscious analgesia which could be maintained and adjusted as necessary over a period of time lasting from a few minutes to several hours.

[12] The 15 milliliter supply of methoxyflurane would typically last for two to three hours, during which time the user would often be partly amnesic to the sense of pain; the device could be refilled if necessary.

[10][19][20] Patient Controlled Intranasal Analgesia (PCINA or Nasal PCA) refers to PCA devices in a Nasal spray form with inbuilt features to control the number of sprays that can be delivered in a fixed time period.

An adhesive is applied to the intact hairless skin, while a small electric current allows the ionized drug to cross the stratum corneum to deliver the analgesic dose upon the device being triggered by the patient.