Exploring Narcotic Analgesics

Summary:

Analgesics are of two types: narcotic (e.g., morphine and heroin) and antipyretic (e.g., aspirin and indomethacin). Narcotic analgesics work by binding to opiate receptors in the central nervous system and periphery, leading to various effects such as analgesia, sedation, and constipation. They can be natural (e.g., morphine, codeine), semi-synthetic (e.g., heroin, tramadol), or synthetic (e.g., meperidine, fentanyl).

Morphine is a natural opium alkaloid with potent analgesic effects but low oral bioavailability. It has various uses, including pain relief in severe cases, pre-anesthetic medication, and treatment of pulmonary edema. However, it also has numerous side effects and contraindications, such as addiction, respiratory depression, and gastrointestinal issues.

Codeine, another natural opium alkaloid, has similar effects to morphine but with less potency and a lower risk of addiction. It is commonly used as an antitussive and for mild to moderate pain relief.

Heroin, a semi-synthetic derivative of morphine, is highly lipid-soluble, leading to a rapid concentration in the brain and high addiction potential. Synthetic opioids such as fentanyl and its derivatives are highly potent and fast-acting but carry the risk of respiratory depression and muscle rigidity.

Methadone is a synthetic opioid used for the treatment of morphine addiction and dependence. It is typically administered in a controlled setting and may be gradually tapered to reduce withdrawal symptoms.

Overall, narcotic analgesics are powerful pain-relievers but carry the risk of addiction and various side effects. Their use should be carefully monitored and tailored to individual patients’ needs.

Excerpt:

Exploring Narcotic Analgesics

Narcotic Analgesics

Introduction:
 Analgesic are 2 types:
1. Narcotic (as morphine & heroin): large dose → drowsiness & prolonged use → dependence
2. Anti-pyretic analgesic (aspirin & indomethacin): No drowsiness nor dependence

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Natural Opium Alkaloids

1. Morphine

Pharmacokinetics:
A) Absorption:
 Well absorbed orally, but low oral bioavailability 30% only (high 1st pass)
 lozenges & nasal insufflations escape 1st pass effect.
 In shock, used as diluted I.V., not S.C or I.M?
 Due to impairment in peripheral circulation →, poor absorption and accumulation
 After correction of shock → Absorption of accumulated morphine → toxicity