Misoprostol does not alter the pharmacokinetics of propranolol

Clinical Pharmacokinetics of Propranolol Hydrochloride: A Review

BACKGROUND

Nobel laureate Sir James Black's molecule, propranolol, still has broad potential in cardiovascular diseases, infantile haemangiomas and anxiety. A comprehensive and systematic review of the literature for the summarization of pharmacokinetic parameters would be effective to explore the new safe uses of propranolol in different scenarios, without exposing humans and using virtual-human modeling approaches.

OBJECTIVE

This review encompasses physicochemical properties, pharmacokinetics and drug-drug interaction data of propranolol collected from various studies.

METHODS

Clinical pharmacokinetic studies on propranolol were screened using Medline and Google Scholar databases. Eighty-three clinical trials, in which pharmacokinetic profiles and plasma time concentration were available after oral or IV administration, were included in the review.

RESULTS

The study depicts that propranolol is well absorbed after oral administration. It has dose-dependent bioavailability, and a 2-fold increase in dose results in a 2.5-fold increase in the area under the curve, a 1.3-fold increase in the time to reach maximum plasma concentration and finally, 2.2 and 1.8-fold increase in maximum plasma concentration in both immediate and long-acting formulations, respectively. Propranolol is a substrate of CYP2D6, CYP1A2 and CYP2C19, retaining potential pharmacokinetic interactions with co-administered drugs. Age, gender, race and ethnicity do not alter its pharmacokinetics. However, in renal and hepatic impairment, it needs a dose adjustment.

CONCLUSION

Physiochemical and pooled pharmacokinetic parameters of propranolol are beneficial to establish physiologically based pharmacokinetic modeling among the diseased population.

Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine

In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.

Misoprostol therapeutics revisited

Misoprostol, a prostaglandin E1 analog, is a racemate of four stereoisomers. On administration it rapidly de-esterifies to its active form, misoprostolic acid. Misoprostolic acid is 85% albumin bound and has a half-life of approximately 30 minutes. It is excreted in urine as inactive metabolites. No significant drug interactions have been reported. Besides its gastrointestinal protective and uterotonic activities, misoprostol regulates various immunologic cascades. It inhibits platelet-activating factor and leukocyte adherence, and modulates adhesion molecule expression. It protects against gut irradiation injury, experimental gastric cancer, enteropathy, and constipation. It improves nutrient absorption in cystic fibrosis. Misoprostol has utility in acetaminophen and ethanol hepatotoxicity, hepatitis, and fibrosis. It is effective in asthmatics and aspirin-sensitive asthmatic and allergic patients. It lowers cholesterol and severity of peripheral vascular diseases, prolongs survival of cardiac and kidney transplantation, synergizes cyclosporine, and protects against cyclosporine-induced renal damage. It works against drug-induced renal damage, interstitial cystitis, lupus nephritis, and hepatorenal syndrome. It is useful in periodontal disease and dental repair. Misoprostol enhances glycosoaminoglycan synthesis in cartilage after injury. It prevents ultraviolet-induced cataracts and reduces intraocular pressure in glaucoma and ocular hypertension. It synergizes antiinflammatory and analgesic effects of diclofenac or colchicine and has been administered to treat trigeminal neuralgic pain. It reduces chemotherapy-induced hair loss and recovery time from burn injury, and is effective in treating sepsis, multiple sclerosis, and pancreatitis.

Pharmacokinetic drug interactions with anti-ulcer drugs

The safety profile of any pharmacological agent is defined on the basis of its toxicity, tolerability and potential for pharmacokinetic and/or pharmacodynamic interactions with other compounds, which may belong to the same or to a different pharmacological class. Drug-drug interactions are important in clinical practice because short and long term therapeutic regimens frequently require coadministration of different drugs. The pharmacological treatment of gastric and duodenal ulcers (and of related syndromes) includes older and newer compounds, which have different mechanisms of action and exert different therapeutic effects. These compounds are widely prescribed in combination with other drugs being given for the treatment of concomitant diseases. This article reviews pharmacokinetic interactions with anti-ulcer drugs, paying particular attention to those which have clinically relevant adverse effects. Drugs mentioned in the literature as causing any pharmacokinetic interaction with anti-ulcer compounds are considered in this article.

Misoprostol--a logical therapeutic approach to gastroduodenal mucosal injury induced by non-steroidal anti-inflammatory drugs?

Misoprostol is a synthetic analogue of naturally occurring prostaglandin E1. The basis of the damaging actions of non-steroidal anti-inflammatory drugs (NSAIDs) on the gastrointestinal (GI) tract is believed to be a consequence of two events: a direct damaging action on mucosal integrity and depletion of endogenous mucosal prostaglandins (PGs). Due to the latter effect, and because current evidence indicates that PGs play an important role in maintaining the integrity of the GI tract, misoprostol has been developed as a logical therapy to prevent and heal gastric and duodenal damage caused by NSAIDs. The purpose of this review is to consider the need for such a therapy, to describe its pharmaceutical development, to review its pharmacology and to review its efficacy compared with other available agents.