Megestrol acetate oral
- Drugs List
- Therapeutic Indications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
Oral formulations containing megestrol acetate
Carcinoma of breast
Carcinoma - endometrium
Renal cell carcinoma
Whilst the doses stated below are those recommended by the manufacturer, local cancer network protocols for the relevant indication should be consulted.
The recommended dose is 160 mg megestrol acetate once daily.
At least two months of continuous treatment is considered an adequate period for determining the efficacy of megestrol acetate.
Children under 18 years
Precautions and Warnings
Disorders aggravated by fluid retention
Predisposition to venous thromboembolism
Glucose-galactose malabsorption syndrome
History of depression
History of hepatic neoplasm
Severe arterial disorder
Severe hepatic impairment
Undiagnosed gynaecological haemorrhage
May decrease glucose tolerance in patients with diabetes mellitus
Treatment to be prescribed under the supervision of a specialist
Monitor renal function in elderly patients
Prolonged or high dose may lead to adrenal suppression
Female: Ensure adequate contraception during treatment
Megestrol acetate may cause adrenal suppression. Replacement treatment with glucocorticoids during periods of stress may be required.
Use in elderly patients should be cautious due to the increased likelihood of decreased hepatic, renal or cardiac function, and the concomitant use of other therapies.
Megestrol acetate is primarily excreted by the kidney and thus the risk of reactions may be greater in patients with impaired renal function.
Pregnancy and Lactation
Megestrol acetate is contraindicated during pregnancy.
There are reports of an association between intrauterine exposure to progestogens during the first trimester of pregnancy and genital abnormalities in male and female foetuses. The risk of hypospadias in male foetuses may be doubled by exposure to progestational drugs when compared to the general population.
If a patient is exposed to megestrol acetate during the first 4 months of pregnancy or if she becomes pregnant whilst taking megestrol acetate she should be advised on the potential risks to the foetus.
The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Megestrol acetate is contraindicated in breastfeeding.
Due to the potential for adverse effects on the nursing infant, breastfeeding should be discontinued during treatment with megestrol acetate.
As megestrol acetate is a progesterone derivative, its effects are probably similar to other progesterone therapies, which includes the suppression of milk production. It is suggested that very little natural progesterone is available to the infant via milk and so it may be true that the direct effects of progesterone treatment on the infant will be limited (Hale, 2014).
Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
Specialist advice is available from the UK Drugs in Lactation Advisory Service at https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1
Altered glucose tolerance
Carpal tunnel syndrome
Exacerbation of diabetes
Impaired adrenal function
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Last Full Review Date: October 2016
Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. Accessed on 17 October 2016.
Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.
Summary of Product Characteristics: Megace 160 mg Tablets. Swedish Orphan Biovitrum Ltd. Revised February 2015.
The Norwegian Porphyria Centre (NAPOS).
Available at: https://www.drugs-porphyria.org
Last revised: 14 July 2010
Last accessed: 27 October 2016
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