solvent with sufficient solubility for that drug formulation) for the vast majority of substances, let alone parenteral or specifically IV use. A more appropriate non-parenteral consumption route to label as being "only marginally slower" to IV use would arguably be smoking/vaping (assuming the drug exists in a molecular form conducive to combustion/vaporization. Arguably The bioavailability of drugs administered nasally is generally significantly higher than drugs taken orally. Generalizations aside, the degree of relative bioavailability variation (with such large variations also including decreased relative bioavailabilities, with both variables unique to particular drugs in particular formulations) between nasal and oral administration in any one particular randomized drug is high. For example, two specific commonly prescribed or otherwise consumed drug classes, whether licit (e.g. majority of commonly prescribed non-IV Benzodiazepines) or illicit (e.g. Cannabis (drug) and arguably the majority of directly cannabis-related synthetic cannabinoids), are prime examples that refute this presented overarching claim the nasal use "generally" results in improved bioavailability relative to oral use. While the examples listed below may benefit from nasal use in terms of improved bioavailability, numerous pharmaceutical drugs possess results contradictory to the "nasal use generally absorbs more efficiently" narrative. Generally speaking, drugs that are either water insoluble or negligibly water-soluble tend to possess extremely poor bioavailability rates resulting from mucus membrane-related consumption, whether nasally or rectally (if consumed in solid, particulate form). In addition, nearly all drugs with improved nasal bioavailability (relative to oral consumption) possess either an equivalent or outright superior bioavailability when consumed rectally, particularly via an extremely low volume enema (assuming said "micro" enema is administered via a non-toxic, human tolerant solvent with appropriate solute-related solubility) that is intentionally not expelled from the body. Such "micro enemas" usually require <2-10ml of solvent for the majority of common drug dosages. Examples of drugs given Steroids (local effect) and anti-asthma medication Hormone replacement Decongestants (local effect) Nicotine replacement Migraine medication Vaccines Nasal administration can also be used for treatment of children or patients who are otherwise alarmed or frightened by needles, or where intravenous (IV) access is unavailable. History In the 18th century, the tobacco smoke enema, an insufflation of tobacco smoke into the rectum, was a common method of reviving drowning victims. References Medical terminology Routes of administration