Automated intravenous delivery systems have recently become commercially available for intermittent self-administration of analgesics. Patient-controlled analgesia (PCA) has been used effectively to relieve after a wide variety of surgical procedures. It has also been effective for pain associated with labor, sickle cell crisis, and chronic pain caused by cancer.

Fentanyl, a synthetic opioid previously available for parenteral use in anesthesia (Sublimaze, and others) and in a transdermal patch for chronic pain (Duragesic - Medical Letter, 34:97, 1992), has now also been marketed as a raspberry-colored lozenge on a plastic handle (Fentanyl Oralet - Abbott), which resembles a lollipop. The new formulation will probably be promoted mainly for premedication of children before anesthesia, but has also been approved by the US Food and Drug Administration (FDA) for preanesthetic use in adults and for use in anesthesia or 'monitored anesthesia care' in...

Fentanyl, a synthetic opioid previously available for parenteral use in anesthesia (Sublimaze), has now been marketed in a controlled-release transdermal formulation (Duragesic - Janssen) for use in patients with chronic pain severe enough to require opioid analgesia. It is not recommended for treatment of postoperative pain because of the drug's slow onset and prolonged duration of action.

Fourteen states in the US - Alaska, California, Colorado, Hawaii, Maine, Michigan, Montana, Nevada, New Jersey, New Mexico, Oregon, Rhode Island, Vermont and Washington - now permit, or soon will permit, some medical use of marijuana (Cannabis sativa). In some states, licensed facilities dispense botanical cannabis by prescription. In others, limited self-cultivation is permitted for medical use.

The FDA has approved tenapanor (Ibsrela - Ardelyx), a sodium/hydrogen exchanger 3 (NHE3) inhibitor, for twice-daily oral treatment of irritable bowel syndrome with constipation (IBS-C) in adults. Tenapanor is the first NHE3 inhibitor to become available in the US.

Sumatriptan (soo ma trip' tan; Imitrex - Glaxo), a serotonin (5-HT) agonist, is now available in Canada and may soon be available in the USA for oral or parenteral treatment of migraine headache. The parenteral formulation is designed for patients to inject themselves subcutaneously. Sumatriptan is not recommended for prophylactic use.

Tramadol hydrochloride (Ultram - Ortho-McNeil), a centrally-acting analgesic marketed in Germany since 1977, was recently approved by the US Food and Drug Administration for oral treatment of moderate to moderately severe pain. Despite some opioid activity, tramadol has not been scheduled as a controlled substance.

The FDA has approved two new drugs for sickle cell disease: crizanlizumab-tmca (Adakveo – Novartis), an IV P-selectin blocker, and voxelotor (Oxbryta – GBT), an oral hemoglobin S (HbS) polymerization inhibitor.

Cannabis (marijuana) contains more than 60 pharmacologically active cannabinoids; delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the best known. THC is the main psychoactive constituent of cannabis. CBD, unlike THC, does not produce intoxication or euphoria.

A new once-daily formulation of gabapentin (Gralise – Depomed) has been approved by the FDA for treatment of postherpetic neuralgia (PHN). Immediate-release (IR) gabapentin (Neurontin, and others), which has been available in the US since 1994, is also approved for this indication, but is taken three times a day. Extended-release gabapentin enacarbil (Horizant) was recently approved by the FDA for treatment of restless legs syndrome.